THD Flexi 50 Head

No idea what year this amp was made, bought new however.
1-channel, but the boost & master features make it seem like 2.
FX loop is eries: quiet & effective.
Biasing is really something, and the ability to use various /different tubes is great. 50/20 watt adjustability makes it great for studio, rehearsal, or stage. It morphs most amp sounds plus has it's own dynamic & touch-sensitive abilities.

Works well with single coils or HB's, and any style of playing.
Absolutely quiet, but if you load the front end with pedals or chains of stuff, you will hear anything unless you buffer them.
From twang to smooth to bluesy to screwam: it covers the gamut.
Also chimes quite nicely!

Like a tank it is - bottom line.

Have felt the need to contact them, but they have a superb rep and also have a great rating with the BBB in Seattle. Just wrote them about the warranty. Their website is EZ to navigate , and they have new products to morph this unit into a combo or in a head cab.

After 40 years, I think this will take the place of all my big stuff. Feature-packed, compact, and "flexi"-ble. Just what I was looking for. The YouTube videos, reviews here at HC, and magazine reviews do not lie. Have Bogner, Fuchs, Mesa, Vox and more in my stable. This piece just moved up to the front of the line-up.

Don't know what year but serial is 0491.
Amp is crazy versatile. I play everything from Country, Church, Rock, Blues, Metal. Depending on your tube choice you can get anything out of it. A very cool feature on this amp is you can bias the amp right on the back. No jacking with taking the cover off or anything. It is even printed right on the back what the settings should be. Makes switching tubes a breze. All you need is a voltmeter.
Not quite 2 channel, but a footswitchable boost and master volume. You can control the amout of gain boosted, and the boost has a tone adjustment. Super effective. Has one effects loop which is very clean. I use this amp in church and in a rock/country cover band. The power is fantastic. 50/20 watt switch only adds to the tone choices.

I play a les paul, strat, and a early '90s yamaha pacifica. All sound amazing. I have never owned an amp this sensitive to dynamics. I have owned Peavey 5150 head, Mesa Reto-verb head, Mesa MarkIV, and Mesa f-30. This amp kills them all. When you know what you are doing with real tube amps like this one, you can dial up any sound with it. Each and every knob makes a huge difference in tone. You can hear the difference between all your pedals, and guitars. Finally I can hear all the mods in my Keeley pedals, and in my Fulltone pedals.

Seems like a tank. I would totally rely on this amp.

Have never had to use them, but have only heard great things about them.

Love this amp. Will NEVER get rid of, or sell. Have been playing for 15 years, and have never come across something this amazing. If lost I would shoot myself for being so incompetent. If stolen my 9mm will be looking for your tail. I compared it to all the boutique amps made. Picked this one because it is by far the most versatile.

purchased amp 4 mo. ago tube swaping is endless old lion kt66---beautiful bell basman sound eh kt 88 lots of headroom valve art el34s my personal favorite pre amp tubes make a bi diff too.. i tried mullards jan phillips chinese tung sol believe me they all make a diff it all depends on the use of application and you tweakin abilities

sound quality is where this amp shines its by far the best ive played ive owned a 63 bassman a black face twin 73 super lead 75 master volume sound city peavey heritage jcm 800 and more.. vintage marshalls have always been my favorite until the flexi 50 came along ..i have a custom shop strat a classic les paul js1000 and i just purchase a jackson rr5 each guitar takes on its own personality through this amp like none ive ever heard.. the key to the sound is in the tweakin of the amp..with the jackson i have to completely re eq the amp relative to the strat which the pick ups arent nearly as hot.. but when u find that sweat spot its amazing..

looks like a tank.. feels like a tank... i really dont know though ..like i said ive only owned this amp for 4 months hope it lasts like my marshalls

havent needed it yet ....

ive been playing for a long time..25+ seen aa lot of crazy stuff over the years heard a lot of good and not so good equiptment played many a club marshalls have been by far my best experience over the years old ones too... not the new ones although i havent payed the hand wired.. this thd is a keeper and is my presant amp i use to gig with ...wouldnt change a thang,,,

Amp was made in 2003. I primarily use the amp to play with friends and out occaisionally. Lots of tone shaping possibilities which could possibly be the reason some find it difficult to dial in a sound - extrememly sensitive to small changes. Love the fact that you can swap tubes - I can get chimey Fender to classic marshall no problem - metal requires a foot pedal to get close. To me the 20/50 watt setting has a lot more to with the quality of sound than the "amount" of sound. No reverb is bothersome.

I primarily is my JET Earlewood with this amp which has the ability to switch to humbucker of single coil. I have a ton of pedals, but mainly use analogman tube screamer, Anlgmn Boss DS-1, Angmn Chorus and HK reverb/echo. My band plays a huge spectrum of music - so, I find myself missing a channel switching amp at times. However, when I dial the sound in I am looking for this amp is as sweet or brutal as I want. I can see where others may have difficulty getting "a sound" from this amp - several times I questioned whether I liked this amp or not because I was spending time trying to recreate a particular sound. When I decided to find my sound is when I really began appreciating this amp.

My experience is this amp is built pretty solid. I move it around a lot and have never had any issues. Never needed to call THD.

No experience.

I've been playing off and on for 20 years - moreso in the past 5 years. If stolen, I might consider a channel switching amp, but in the end I would probably replace the THD. I might even consider a second THD and set it up differently. I receive many compliments on my sound and I happen to like it too.

Everybody knows the features, I'm not going to list them here. Lots of "candy" and things that seem great in theory, but ultimately are useless in practice!

Well, this is the MAJOR stumbling block for this amp. It just plain sounds awful on anything other than totally clean settings. Tried with a multitude of different tubes and a plethora of guitars, it always sounds like a piece of sh*t. A damned smelly piece, too! Just how the hell THD has created those wonderful soundclips in uses to promote this woeful amp is beyond my understanding. Must involve tons of outboard gear and studio trickery to create those tomes, because they just don't exists inside this sucker.

Seems reliable, but sounds like sh*t.

No idea, never bothered with them.

Compared to almost anything on the market, this amp sucks big time. It is incredibly bad sounding! And incredibly non-versatile. From all the frothy, rapturous write-ups it has had, I can't help but wonder if the reviewers were testing a different amp to the one that THD sell to the general public. Seriously deficient in every category, even the FX loop is a useless primitive piece of sh*t. Awful amp! Fortunately I was able to unload it on Ebay and get my money back. Shame, THD, shame!

Yowza, where to begin? This amp has a plethora of unusual options including footswitchable boost (with it's own gain and tone) and master volume (I find this particularly useless)as well as an input hi/low switch, and the ability to use almost any tube in existance to tweak your sound with. Another feature, in my eyes anyway, is the ability to carry a fifty watt amp around like it ain't no thing. It's about fifty pounds and appears to be about the size of a loaf of bread on steriods. Very useful in my opinion.

Let me start by saying I didn't love the overdriven sound it makes, although I did find a lot of good sounds in it. It just didn't give me a useable version of the Marshall sound I assumed it was going to create. The majority of everyone else posting here says otherwise, so I'll take their word for it, as they own it and I merely auditioned it, using a GE Smith Tele and a Gibson ES 339, as well as two Jetter pedals (red and blue) and my Landgraff Dynamic Overdrive. I also ran a Lee Jackson Mr. Springy reverb pedal, a Diaz Texas Tremadillo, and a Mad Professor Deep Blue Delay through the loop. The distortion pedals all sounded fantastic, better than any other amp I've tried them on. The pedals ran through the loop sounded reasonable, but I think they'd sound better run through the front, making the fx loop more of a feature to list on a brochure than a functional aspect of the amp. Regardless, I think that this little beast is great. I may end up buying it if I can find a better sounding reverb unit to run into it, but this is a small beef. It seems to be the perfect pedal player amp, and I can only imagine switching tubes will only further add to tonal variations.

No idea. The general consensus is that they're tough little bastards, and I'd be pretty comfortable gigging without a backup, maybe bring some spare tubes along just in case.

I called THD after my experience and asked them a few questions and they were more than happy to talk about their products with me.

I really liked it because it made my pedals sound pretty damned excellent. As a stand alone amp I think it'd be somewhat limited, but that's not much of a consideration for me as I'm basically looking for a small and awesome amp to run a bunch of pedals into. This would definitely fit the bill. A little spendy, yes, but an intriguing concept for an amp, and I'd be comfortable assuming that it'd be an investment that I'd have around for a long time.

The Flexi has a lot of features you expect (FX loop, eq), some less common (cut and tone knobs) and some features NO other amp has (tube swapping, easy re-biasing). I gig consistently with it in a rock/variety band. The master/boost foot switching capability makes the amp versatile enough to play in a band that handles a lot of different genres, but, being truly one channel, if you've got the amp tubed for a great dirty sound, it never gets really clean via a click of the "boost" switch and vice versa. I've found that it's close enough for my tastes, and the sweet tones you can dial in override this slight shortcoming.

My other beef is that, unlike the Univalve, the Flexi does not have an attenuator built in, presumably because of the complication of heat dissipation in a higher power amp. So, to get the full benefit of hearing different types of power tube saturation, you have to buy a Hotplate, or practice at full, ear-shattering volume.

The feature feature is the tube-swapping capability. Owning this amp is like a history lesson in tube amplification and provides countless hours of tinkering.

I run no effects and use both humbucker and single coil guitars. The whole point of the Flexi is that it has multiple personalities. And the different personalities the amp take on are based on the unique characteristics of different tube combinations rather than shallow modeling effects. Different tube types not only vary in distortion and tonality, but in sustain and response.

When I first got the Flexi, with it's stock tubes, it sounded kind of stunted to me, but the brilliance is in the capability to experiment. Right now, I am hooked on 6L6's for a present, more saturated sound. Last week, I ran El34's for what was nearly spot on old-school Van Halen "brown." KT88's are sweet for clean-ish jazz and Chicago blues. I use JJ Tesla tubes almost exclusively.

You can get anything from clean to SRV to ACDC to Malmsteen with some trial and error.

I have yet to have any concerns with any THD equipment. It turns out, you can even drop it.

This is easily my favorite amp. It takes time--you have to experiment for days, maybe weeks, with different tubes to find that sweet spot. But when you do, you do. I get guitarists at set break at every gig that compliment my tone and want to see my rig.

Also, this amp doesn't hide mistakes well. You have to be a good guitarist or willing to work your technique, or you'll hate it. But who wants to listen to a sloppy guitar player behind a wall of gain and effects anyway?

All of them are usfull

This is my favorite amp. Nothing I have played comes close. The harmonic are unreal

I never had a problem with it.

Ed and Andy and the rest of the THD family have always been good to me.

I have been playing 37 years at this time. Do I need to say more than this is the best amp I have ever played.

The Flexi 50???s features have been well stated by previous contributors. The Line- Out is fantastic. THD is one of the few manufacturers that have this area figured out. The tube swapping ability allows you to tailor the gain range and feel to suit your needs. I do not feel that this amp is a chameleon that can replicate the sound of the best vintage amplifiers. The Flexi has its own sound. The tube-swapping does affect the character, and how the amp reacts in a very audible and useful way. The Flexi is not a true channel-switcher, but you can set it up so that the Boost acts as your dirty channel. I wish that you could use the footswitch to toggle the lo/high input and the boost function independently. I still give it a 10 because the design is well thought out with many useful features that do not detract from the tone.

To start, let me say that I have found most of the reviews on this product to be exceedingly accurate. I have owned the Univalve, the Bivalve, and now I have settled on the Flexi. I play many styles of music including rock, blues, hip-hop, jazz, funk, r & b as well as some of the hard stuff. I play a Les Paul and a Tele and I use a Dr. Z Airbrake attenuator. Just as a base of reference, my favorite amplifiers aside from the THD line include: Marshall JCM 800 (good ones are very hard to find), Fender Super Reverb, Fender Vibro-King, Matchless DC-30, and Vox AC-30. The Flexi brings out the best in both guitars and brings out the differences in pickups and wood. It does clean tones, driven clean, and distortion equally well. The low end presence is excellent and you can achieve that percussive low end snap heard in Marshalls and Fenders. There is plenty of bass on tap, without any muddiness. Others have described the Flexi as a cross between a Marshall and a Fender with some AC-30 thrown in. I agree. The THD amps definitely have their own sound though.
The Flexi is extremely touch-sensitive and is a joy to play. In fact, the THD line has ruined most other amps for me. They feel sluggish in comparison. I can no longer stand to use overdrive/distortion boxes. I find that the Flexi, with its great sustain, allows me to connect notes easily and thus makes it a very forgiving amp to play in that respect. Sound characteristics are very difficult to describe, but I will do my best. The tone is 3-dimensional, meaning there is harmonic activity after a note is struck. Notes bloom. The bottom end is very tight. Even at high gain settings, you can hear each individual note in a chord. The Flexi is plenty bright, though not nearly as bright as a Marshall Plexi. It has a unique midrange that sits a bit lower in the frequency spectrum than that of a Marshall, and cuts well in a live situation.
I had the chance to a/b the Flexi with a Marshall Plexi Reissue. It is my opinion that the Flexi can do just about everything that the Marshall can do, and a million other things. I found the Plexi RI to be much looser and sloppier animal while the Flexi has a much tighter, more refined sound. The Marshall is way brighter which some players may prefer, especially those who are trying to accurately copy the Jimmy Page thing. It???s a very cool amp, but to my ears the Flexi blows it out of the water.

I have gigged extensively with both the Bivalve and the Flexi and I have never had an issue with either. One of the great benefits of the tube-swapping capability is that there is no need to see a tech. These things are built exceptionally well. I would feel confident buying one on the used market.

I have never had an issue with any of the THD products.

The THD Flexi represents one of the best values on the instrument market today. I have gone through over a dozen amplifiers in the last few years trying to find my sound: JCM-800, Marshall Slash Signature (Jubilee), Fender Super Reverb RI, Mesa Boogie DC-5, Fender Deville ???among many others. Being a career musician, I have had the opportunity to test out much of the high end gear out there as well: Bogner, Budda, Egnator, VHT, Dr. Z, Gibson, Top Hat, Victoria, Vox, Matchless??? So far, the Flexi is my hands down favorite.

see my prior review

Just wanted to update my prior review. I have now had this amp a couple of months, and the honeymoon is still not over! I am now running GTEL34M power tubes, v1 GT12AX7R, v2 GT12AX7M, v3 12AX7C preamp tubes into a 16ohm THD Hot Plate into a custom 4x12 cabinet loaded with Celestion 70/80's. My guitar is a Fender MIM Fat Strat with a Floyd Rose, loaded with a Seymour Duncan Custom Custom trembucker. I still have NO complaints with this amp, it sounds killer. The classic brit style crunch is incredible, I still feel like I got one helluva deal.

Still works perfect, very solid build.

I have spoken with Ed, about a Hot Plate issue, awesome guy, very helpful. THD really gets an 11 here!!

Absolutely no buyers remorse, I only wish I had bought this amp first and saved all the money I spent on other inferior heads. If you like classic Judas Priest, Iron Maiden or even early Van Halen with some tube experimentation this amp will nail that tone, But where it really excels is at giving you YOUR tone. One other thing that still irritates me is the guy who reviewed this amp in Guitar World put down as a CON "no high gain option". Duh! This was designed to produce classic rock tones in the style of the jcm-800 and plexi, not Nu-metal tones. That is like saying a Mesa Dual Rectumfrier has "no Vox AC15 option" Apples to Oranges dude!

I've played 40 years and owned a dozen amps. This is what I've been looking for my whole life. The best Marshal tone I've ever wanted with lower lows, higher highs, and a low midrange with mind blowing complexity and harmonic content.

Simply breath taking. Tons of headroom. Id NEVER give this up. THe clean boost is the best I've heard. Really exposes the flaws in my pedals.....Its like a science lab.

Built like a tank. best build Ive ever seen.

The best. I called three times about tube choices and they were totally helpful!

I play, rock.blues, jazz, funk. It does it all. Totally dynamic and responsive to my guitars volume control.

THD Electronics Flexi 50 head. #214, Extremely versatile controls, volume, treble, midrange, bass, bright switch, input hi/lo switch, boost switch with gain and global tone, master volume with bypass switch, cut (presence) control, effects loop, line out with level switch and control knob, two speaker jacks, impeadence switch, external bias check points with adjustment controls, switch input to high with boost switch, footswitch jacks for the master volume and boost circuit, and the designer, Andy Marshall's signature with plexiglas cover right on the back, cool huh? the external bias contrrols alone make this one woth a 10. How much would you save a year on trips to the amp tech, just for new tubes and a bias?

I installed (2) Groove Tubes GTEL34M's for the power section and the pre amp now consists of V1 GT12AX7C, V2 GT12AX7R-2, driver is a GT12AX7R, all new. With the boost engaged this combination delivers a better than authentic JCM800 tone. Turn off the boost and there is that sought after Plexi tone. Putting a 12AT7 in V2 as recommended by the manufacturer yields a chilling early rock tone anyone would fall in love with. Very responsive amp, will make you a cleaner player. No where to hide sloppy chops, this thing is as articulate as any amp out there, note clarity is hands down the finest I have heard. Truly a quiet amp, even at extreme settings, it hums just enough to let you know it is ready to erupt at your command. All of the various controls and switches are dead silent, and very usable. Nothing here you would look at and say "why?".

I have only had the amp for a week now, so I am going to be honest and say no opinion. But I will say it seems to be built to survive. Everything is seems to be of the highest quality, it looks, feels and sounds very solid. I really expect years of trouble free service, how many used amps can you feel that confident about.

Here's one you never heard before. I purchased this amp used from an online auction site(yes, the E word), and thought it was not going to include the manual. I emailed customer support telling them my dilema, and requested a manual. Les than three hours later , I had the file sitting in my in box with friendly reply. Wow, fast you say, huh? Now, this was on SUNDAY afternoon. Customer support, on sunday? It is true, cross my heart! The manual was included with the amp, just to give Music Go Round in Novi thier credit, thier customer support is also top notch. Thanks again guys!

I went through the disappointment of trying to get my sound from large company produced budget tube amps, Crate(bv60h), Peavey(windsor,valveking), Epiphone(socal50h), Marshall(avt50h). The one thing they all share in common, when really pushed to loud volumes the sound just goes to mush. Why make a 50 or 100 watt head that only sounds good a quarter of the way up and then just starts a downward spiral in the muddy mess the louder you go. Then I decided to get the amp I originally wanted but Thought was too much money to spend. Well, I spent triple the new price of a Flexi trying all the others. After playing this amp for a week, I realize how expensive this lesson really was. This amp is by far the most versatile amp on the market.

All this info has been covered elsewhere in these reviews. This amp tries to cover lots of ground, but most of it I consider a waste. For all intents and purposes I consider it a 2 channel amp, but I was happiest when I treated it as a non-master volume single channel amp running on full power. The clean settings give you wonderfully sparkley tones, but I don't care for the overdrive at all. Obviously many of the reviewers like the overdrive, and it's there if you want it. One thing nice about this amp is it's LIGHT. That's important when you get tired of lugging 70 lb. combos around.

Like I said, the clean tones are great. Set it for full power, non master volume, and you get glassy, chimey, and harmonically rich tones. Very pretty. Sounds great both with my Strat or my Les Paul. But that's where it ends for me. All the other bells and whistles are just a waste. The over drive (boost)is harsh and not musical at all, in my opinion. Very uninspiring. Use a good pedal if you want gain. The master volume settings were equally unimpressive, since I don't care for the amp's overdrive sounds. I tried all sorts of different tubes and the results were always the same. That's too bad, because I bought this amp hoping I'd be able to achieve nice tube overdrive at a lower volume. The overdrive tones on this amp never sound good. I like the clean tones, but I have to knock it because the overdrive sucks.

I owned this amp for about a year before selling it. It seems to be made very well, and THD has a great rep. I never had a problem, and never had to get it serviced. Never gig without a back up. You may have the best amp in the world, but tubes fail and soldered wires can disconnect and nothing lasts forever.

THD has a great rep, but I never dealt with them.

I've been playing 20 years and have been through all sorts of amps. My current keeper amps are a Fender Vibro King, Whitney MV34, Bassman Reissue, '73 Princeton Reverb, and a Musicman 130-212. I was very disappointed in the Flexi-50, especially after reading all the glowing reviews.

You can find a better description of the features else where
But here are some things you should note:
Tube bias system- use any power tubes you like
Tone controls- more like a 3-band eq, makes it so much easier to dal in a specific sound
Master control-gives you four fot switchable sounds:
1. clean rhythm
2. clean lead
3. rhythm overdrive
4. lead overdrive

Wish it had:
2 independent channels
Reverb
No Cut control

I'm not going to compare this amp to any other amp, because the majority of us, like myself, have never played a vintage marshall, vox, or fender. Those amps are for collectors, not players.
i am using an '81 les Paul studio straight into the amp, and have a 2x12 Avatar cabinet w/ celestion lead 80's.
This has an outrageously clean tone. I prefer the ton controls set to a mid scoop which gives it a bell like, even acoustic qualities. 6L6's and 6V6's have the best clean tones. Use 6L6's if you need more head room.
EL34's and 7581's are better for overdrive.
The boost control is not another channel, its a volume increase.
so if you want a nice crunch tone, you have to peg the boost and switch in the master to control the volume. to get more distortion, all you have to do is turn up the volume and turn down the master. If you have the volume past three, it will start to compress which is distracting when you try to play fast.
Your speaker choice will be crucial to your sound. if plan to focus in on a overdrive setting, you may want a greenback or a V30. The lead 80's are very clean and very articulate, so they match with the flexi because it has the same qualities. My favorite over drive setting w/ the lead 80's is "smooth upper mids" setting in the manual, basically a mid boost.

Built like a tank, weighs a ton
everything is well thoughtout on this amp
becareful of liquids because the chassi is exposed to this due to the holes in the role cage.

Great.
talk like humans to you
respond quickly on emails

Cleans, cleans and more awesome cleans make this amp a winner in my book.
If you want footswitchable distortion, get a Mesa. dont bother with this amp.
If clean is what want, go wih amp, you will not be disappointed.
it really says want it to say when your playing.
Check out Avatar cabs if want a decent cab with nice speakers.
the flexi is a truely awesome and revolutionary amp.

Footswitchable Master volume & Overdrive boost. Bias controls on back mean you never have to buy tubes in matched sets again. Speaking of tubes, put pretty much whatever you want in this sucker! I've tried EL-34, 6L6, and one of each and it sounds great with all of them. Can't wait to try some EL-84's with my new Yellow Jacket converters! 50 watts of sweet, totaly configurable tube power. Half power switch drops it to 20W for even more FLEXIbility. Use a wide selection of cabinets too. I really miss not having reverb, but the other features of this amp almost make up for that.

Marshall Plexi tones to die for. Distortion totally controllable with master vol & boost. Sky's the limit for sounds and tones on this baby...Marshall, Fender, Vox and more are all there with a quick tube swap and re-bias.

A sherman tank should be built this tough!

Ed Genaro and his supports staff are the best I've ever dealt with...barre none! Nead a manual, PDF emailed to me. Problems with some yellow jackets, replaced no questions asked. Questions to be asked...answered promptly. I can honestly find no fault with the customer support...a few other companies should take notes here!

I'm normally fairly critical, so hats off to these guys for making the best amp I could find at a really fair price (not cheap, but very fair).

All knobs and switches offer considerable tone and dB shaping. LOVE the individual bias feature. The only change I'd make would be to make the input gain footswitchable.

This amp has a unique voice, which is probably more reminiscent of Marshall in it's hey-day, but more refined. I've owned Marshalls from the '60s, '70s and '80s, as well as a handful of Fenders, a couple of Boogies, a rack rig with an ADA MP-1, and a few "boutiques." Currently, I have 7 amps, including a handwired Marshall, Vox, Fargen, Fender, etc., and I have to say that the Flexi is the one I grab for EVERY gig, week after week, regardless of whether it's to play classic rock, funk, blues, or jazz.

I have a Les Paul Standard, a Strat, a Tele, and a couple of other guitars and use a mix of Duncans, Texas Specials, and Fralin pickups. I'm a bit of a pedal nerd with a decent collection of overdrives, treble boosters, and distortions built by Keeley, Fulltone, and other "boutique" brands. I also have used a wide variety of tubes in this amp, both new and NOS. The point to all of this, is that despite the subtle variations created by all of these things, this amp always sounds great. Does that mean that it will, or that it should, be perfect for everyone? Of course not, however, if you understand it's niche and then spend some time with it, you'll be rewarded. It took me a while to understand the preamp design, the unconventional controls, and so forth, but once I did it went from a nice sounding amp to "the sound in my head."

To me, these are the tricks to this amp:
1. It sounds best with the "boost" section on all the time, and thus I don't use the footswitch. I'd imagine that gain freaks peg the boost control, but I find that it works best if you back off of it just a bit.
2. You have to use the volume control above 12:00...I prefer it at 3:00-ish. Above that you may find it to break up and compress sort of like a fuzz tone, so again, pegging this control doesn't work for me. This amp is very much about smacking the output, so cranking the volume (within it's "sweet spot") is crucial...thus it's best to use an attenuator for reducing volume (except where 20 watt mode and subtle reduction of master, boost, and cut controls can sound great to reduce volume by, say about 4dB).
3. Keep the bass control down.
4. Most room eq-ing is done with the cut control.
5. The master thins it out too much for me...a hotplate is better (however subtle master settings are nice to add some bite).
6. This amp is capable of a fair amount of high end...thus I don't like it as much with Celestion 75s or V30s...better with H30s and Classic Lead 80s.
7. Like any amp, this front end likes some pedals more than others. Likewise, it may require different settings on pedals and guitars. It is highly sensitive, thus very dynamic, but it will also reveal some things you probably didn't hear with other amps.

Excellent! Really heavy duty. No problems.

Superb...really nice and helpful people. In addition, the users forum

http://www.univalve.net/forums_new/

has been very helpful in tweaking it to taste.

I've been playing about 30 years, and for the last two, this has been just about the only amp I've used. The Flexi-50 is appropriately named...I play a wide variety of gigs and venues, from weddings to outdoor festivals, and have never had a problem dialing it in. Simply an excellent value.

My Flexi is an 05. I play a number of styles, from heavy space-rock to jazz, to blues on occasion, to straight up STP style rock. This thing covers them all. The ability to use any kind of power tubes with this thing is incredible. It's amazing how the character of this amp changes with tubes. I use this head in small to medium size clubs, and I've used it on an outdoor gig once. It handles every situation just fine. I have to say that I always use my tone for every type of style I play. My pick attack, my guitar, and other factors in the way I play change according to the needs of the moment. This amp doesn't have a ton of knobs, channels, or options on its own (unless you count being able to use any type of power tube or preamp tube and completely change the character of the amp), but it is the perfect amp to use as a starting point to add your stompboxes and other accoutrements.

The ability to rebias in a matter of minutes yourself will save you a TON of money, and make your tubes last much longer.

I use a PRS Custom 22, a Hamer USA Studio Goldtop, and a USA Hamer Artist. I also occasionally use a Japanese strat and tele. It handles all guitars equally well. You know how they say that tone is in the fingers? Well, I believe that's true, but I think your equipment can either let your tone come through, or squash it and hinder your creativity. This amp is one of those that lets your tone come through. It's incredibly sensitive to the subtleties and nuances of your pick attack, your touch, and the type of pickups you have. In addition to all that, it sounds like freakin' BUTTER. Rich, complex, and a depth that I've not heard in an amp at this price.

It has plenty of clean headroom, though you can change that with a set of power tubes and a different driver tube. I've been able to get very convincing Fender tones, Marshall tones, Vox, Tweed Fender, and a bunch of others just through changing the tubes and resetting some of the switches. If you want to hear the difference between a NOS tube and a current one, this amp will REALLY let you hear the difference. Here's the thing- this amp, in and of itself, doesn't do the channel switching, clean to blistering distortion at the touch of a switch thing. It is more geared toward those who like to turn an amp up all the way and use the guitar volume knob, or those who like to run the amp clean and add pedals. I am one of the latter.

The tone controls are unique in that adjusting one doesn't affect the others. They are incredibly responsive, and you can get a wide variety of tones with a bit of twiddling. The one downside is that the amp is very, very bright. So much so that I actually run it with the treble nearly off. It doesn't matter, I still get the tone I need from it.

The amp is incredibly quiet. Even in my house, where I don't have a single grounded outlet, it remains quiet.

I would gig without a backup with no hesitation. Nice to see a well constructed circuit board amp. The chassis is incredibly tough, and it's obvious that a lot of love and care was put into the construction of this amp. I have never had a problem with it, it has never so much as crackled. Considering the quality, I expect that it won't require service anytime soon. I got to meet the designer of the amp, and he told me that he hopes this amp is the amp that people consider a classic 25 years from now. He hopes it'll be the workhorse that people continue to gig with for years. You know, it says something when other amp companies have postings on their website touting the quality of THD amps.

Every email I've sent has been met with extreme courtesy, and quick response. Ed DeGenaro even called me at home to discuss a concern that I had, which turned out to be nothing. This is a company I'm happy to support. It's good to know that they not only appreciate your business, but work to make some of the best amps money can buy.

I've been playing for 17 years. I researched buying my final amp for 2 years. I've owned Carvin, Mesa Boogie, and Ampeg, among others, I tried some other great amps- Bogner, Rivera, Carr, Victoria, Soldano, Bad Cat, Orange, and others. I was seriously impressed with all of the above, and it was a tough decision, but I'm happy with the one I've made. I got this because of its simplicity combined with its versatility and just all around great tone. The one thing I wish it had was an option for reverb, but I don't miss it enough to let it bother me.

If it were stolen, I'd definitely buy another one. I couldn't be happier with a purchase. I hate to give such a glowing review, but I seriously have nothing negative to say about the amp.

You can read about the features in the manual. I play in a classic rock band that gigs every week. This is a basic two (channel switching amp) with an effects loop, which i dont need or use, a direct out jack for going straight into the snake or board, again i prefer a microphone so i dont really need this.(i have gotten great results with a Blue Ball Mic. it seems to sound better that my sm57) It has an interesting tone stack that makes use of a tone control in addition to the regular treb, mid, lows, and presence controlls, also a hi or low input gain switch, and a treble or normal boost switch, giving a variety of options in setting up your sound. It comes with a heavily constructed footswitch to activate the gain and master on/off setting. This amp sounds great in the master volume mode, using the master volume tone stack to shape differing gain structure but to my ears it excells in the normal position with the master volume off. Thats where you can really hear the character of this amp. But it so hard to decide, both modes sound so good and on any given day i may choose either option (depending on the size of the room). The flexi has a 20 watt and a 50 watt option, where the 50 watt setting applies more current to the circuit whereby the tone is altered to a stronger, slightly louder, less compressed sound. I tend to not use boost pedals or overdrives,for the most part and use my volume controll to alter volume. Unles you are using a super clean amp with loads of headroom boost pedals seem to saturate the tone too much for my liking and actually cause it to lose projection. Many times on many amps i have set up a overdrive to sound really great only to find that when PLAYING WITH THE BAND the sound and projection of it sucks. My ideal of an overdrive is to work on the POWER section NOT the preamp section. After i set up my rythem tone and i need a boost for a lead part I WANT THE SAME SOUND.....ONLY LOUDER. A pedal cannot deliver this, so i must make the trade off and just use my volume knob to project solo's . (back in the day i used 2 amps, but i choose not to do this anymore) Every now and then i may use a chorus and in some songs a wah, but thats it. I find it more pleasing to concentrate on the focus of playing and the sound of the guitar rather than an effect. I bought this amp because i heard a player using 1 in his band. He was really stoked about the amp and was very helpfull allowing me to come to their practice to try it out. This amp needs to be tried out at practice with the rest of the band playing. That way you can get an idea of how its going to sound live, rather than sitting in a small room at the music store. Shoot, you can get anything to sound good at a low volume with tons of saturated gain. Its when you're paired up with a pumped up drummer and a angry rythem guitar player and a string poppin bassmaniac, and you really have to open it up is where you can hear the projection and tone and presence of this amp.

I use this amp with les paul customs, standards, and a few different strats a 71 and a newer swampcaster. I play in a classic rock band that plays every week. My current main guitar is a stock 1979 lp custom (custom shop gold top). I have been playing over 35 years, my dad was a recorded opera singer and played 6 different instruments. Sooo..i have been around music and musicians a lot. If you enjoy the tone of the masters (page, beck,clapton,kossoff, etc.), you will enjoy this amp. There are a variety of tones possible with this amp as i will get to later. The whole trick of this amp (and finding your own voice) as a guitar player involves the total sum of the parts ( guitar, strings, pickups,cord, amp, tubes, speakers) This amp does not seem to be noisy and has a variety of fenderish clean to modded marshall tones, but with a lot more bandwith in all areas. I wouldnt classify this amp as a high gain amp, but...with the preamp buried is can get really fat and greasy...ala Leslie West. At 50 watts(w el34's or 6550's) this amp can get louder tha a 50 watt JMP. (my other guitarist uses 1). Or using the 20 watt setting it can replicate marshall high gain tones at a respectable volume. As i grow older i find that false security of having the gain knob buried has left and i find myself seeking tone and sustain rather than gain. This is a great amp for blues, or classic rock IMHO.

This amp seems to be built like a tank. I quit hauling my 50 watt smallbox around as a backup amp. I just take a couple of extra tubes.

Customer support is great. I bought the amp at Indoor Storm used, as a trade in (a young player took it home for a few months, and didnt like it). And i was pleased to find out that Ed said we can start your warranty the day i called, obviously THD is not worrying about this amp breaking down. I have had a few conversations with Ed Degenaro about different aspects of this amp, and was always treated kindly and courteously...and...promptly. One time i e-mailed a question to THD and i didnt even have time to sign off the computer before they replied....Now thats the kind of service i like. BTW the folks at indoor storm are absolutely great to deal with also. KUDOS....

I waited months before submitting a review on this amp. I wanted to test it in live playing situations. So many times i have tried an amp out in the store only to take it on a gig and be disappointed. Now a couple basic things..POWER TUBES.. NOS Mullards(not the re-issues) NOS Siemens, NOS Tesla's, NOS 6550's GE or Tung Sol. Dont even mess with the others you are wasting your time and money. Just get the real shit. Pre amp tubes... I like mullards, telefunkin, amperex, Brimar's, GE's, NOS phillips, tungstrams. I saw 1 telefunkin 12ax7 on this tube dealers site for $425.00...Crazy world we live in..... Q: why do you think they want so much $$$ for these old tubes?????...ANS: because they ROCK. and tube dealers know that some tone fanatic is going to shell out the cash to get that sound. Let me add that the ElectroHarmonix 12ax7 isnt a bad tube, or are the jj ecc803's..nor are the new GT 12ax7 Mullard clone. But each tube has its strong and weak points depending on what you like. But across the board the mullard and telefunkin, and amperex seem to sound the best to me. Now we move on to speakers. The safest speaker to start out with are the V30's i guess. Depending on your tastes there can be many different choices. I have tried G75M's, greenbacks (which dont sound anything like original greenbacks), Weber thames (a nice chime speaker)JBL greybacks (nice clean sound, but dont try and clip them blaaaach)and V 30's. Of all the V 30's sound the best (to me). All mentioned in a 4X12 metal handle old (with J.Marshall's signiture in it ) Marshall cab @16 ohm. Get a good instrument cord. You playin a 2k guitar in a 2k amp and using a $6.95 cord. haaaa... Well that about all i have to offer......good luck....and God Bless.....

20-50 watts, effects loop, boost, self biasing for different tubes. I can't think of more you would need in an amp like this. Very single channel old-school, but extremely versatile.

I should start out by saying I have never felt strongly enough about any product to submit a review like this. I have been in the market for a low wattage tube combo to use at home. I was recently lucky enough to test drive one of these at a Guitar Center with a Les Paul through a Marshall 4x12 cab. I am not crazy into effects, but I do like a little reverb or delay to fatten up my sound normally. I typically walk away unimpressed by most dry amps without some reverb at least. All I can say about this amp is I have never played an amp that actually made me smile while playing it. I am talking about a smile that wouldn't go away for several hours after the experience. I even woke up in the middle of the night a few times thinking about the amp. I won't say it was perfect, but, it came closer to the tone i've heard in my head all these years than anything else i've tried. With the 20 watt switch it was easy to get a cranked Marshall vibe at low volume. The only flaw i could find was it was a little more muddy for rhythym than I would like. I feel confident with a little more time with the amp, it could be dialed out to near perfection. It wasn't the combo i was looking for, but I still can't stop thinking about it.

Seemed very well built. Very heavy for it's size.

I have been searching for the tone in this amp for the past 17 years i've been playing. I didn't buy it because it wasn't a combo, and was a little more money than I wanted to spend. It could very well be the perfect amp tonally for my needs. I just purchased a slightly used Soldano Astroverb 1x12 combo off of ebay based on my experience with this amp and the reviews from this site. If it delivers what reviews claim it could be my last amp purchase. If not I may have to start saving for a Flexi 50.

2005 Flexi-50, very versitile, single channel, boost and master, series effect loop. It has enough power and a very complimentary set of features. I have used this amp gigging, and in my home studio, I am highly satisfied with the features.

This is one of the best sounding amps I have ever heard or owned. You really have to understand how various guitars, pick ups, and tubes work together to get fantastic sounds. I have tried it with the stock EL-34s it came with (excellent), GT-KT66-HPs, and Yellow Jackets with Tesla EL-84s. I have used it with an Anderson Drop Top Classic, Stratocaster Deluxe, Les Paul Standard, PRS Custom-24 and Ibanez RG-520QS with DiMarzio Tone Zone in the Bridge. You can come very close to the Bluesbreaker (KT66 with Les Paul or PRS), Marshall JMP (EL34 with any) Vox AC-30 (EL84 with Anderson or Strat). Certain things don't work as well (Anderson or Strat with KT-66) in my opinion. Also, very nice Fenderish cleans. The amp really shines when played loud with output distortion and no master. Boost for leads is very effective when used in this way, I don't experience the compression others have noted. Really superb harmonics, highly noticable tube characteristics. Again, you must understand how the various factors work together but truly unbelievable sounds when you plan and tweak it. Not for super high gain modern rock as others have noted. Outstanding, phenomenal sounds and gives you the opportunity to learn about tube characteristics.

Build like a tank, small problem with bias diode out of the shop, fixed me up immediately.

Very good. Spoke to Andy Marshall about a small diode problem, dealt with immediately.

Playing for 30 years, definately replace if lost of stole, really unique amp. Many excellent amps out there but the Flexi-50 does perform as advertised once you understand the factors related the the sound coming out of the amp. Could use a true parallel tube driven effects loop but not a real issue.

This is an incredibly versatile amp. You can read the features below ... Plenty of power, depending on the tubes you choose. Paired with the THD cabinet and a power brake, this thing is unbelievable!

I have mine set up as a blues amp...with a little bit of edge. I use my guitar's volume control to push it into distortion. I like the stock tubes ... but swapped the V1 preamp tube for a NOS RCA AT7. Great sound.

Only had it for a short while, but tubes are easy to replace ... looks solid!

Great web site... check below for a great forum...

http://www.univalve.net/forums_new/

By far the best amp I've ever owned or used for that matter.

Single channel
Volume, Treble, Mid, Bass and Presence controls
Switchable Master Volume
Switchable Boost function with gain and tone controls
Bright switch
High / Low input switch
Effect loop
Impedance switch for 2,4 and 4, 8 and16 ohm cabinets
Allows for substitution of virtually any power tube
Easy to adjust power tube bias. Individual bias pots for both power tubes with outputs for a multi-meter.

I have used this amp with: An '89 Strat with stock pickups and a Seymour Duncan ? pounder at the bridge.
A Squire Tele Deluxe loaded with Seymour Duncan JB and Jazz pickups and coil-taps.
An Ibanez S470 with stock pickups
A parker P-38

My musical style is primarily classic rock with occasional, semi-competent safaris into blues and jazz.

I too wanted to love this amp but I think we are still just friends at this point. Here is why:
It all started when I bought a 70-something Traynor YBA-1. It sounds great, I don?t need to use any pedals. But I know the Traynor is going to catch fire any day now so I bought the tank-like THD Flexi in hopes that I could replace my beloved Traynor with a modern and ostensibly more reliable amp.

First off, the Flexi-50 really responds differently with different power tubes so I will treat each individually:

EL34s: Clean, low volume / low boost sounds pretty good. Playing Jazz with a loud drummer is damn near impossible. At high volumes there is very little headroom before serious power amp distortion, nasty compression and clipping take place ? at least for single notes. It did sound REALLY cool playing rhythm in open G on a bunch of Stones tunes. However, on single note runs at high volume / high gain it basically sucks a** (in my humble opinion)

6L6s: At clean or slightly overdriven settings it sounds great -- the amp has a wonderful clean / slightly dirty tone. Think Stevie Ray or maybe Ronnie Earl without reverb. Switch on the neck pickup on a Strat with the boost and volume set at reasonable levels and you should be able to nail a pretty cool blues tone.
It also sounded pretty good at high volume / high gain with the 6L6s but not as good as my Traynor YBA-1.

6V6s: Sounded pretty cool in my bedroom in both clean and high gain modes but there wasn?t enough volume to compete with a spirited drummer. The only time the master volume feature seemed even remotely useful was with the 6V6s loaded

Summary:
* I agree with others that the overdrive can definitely be ?farty? sounding and over-compress. 6L6s seem to help.
* I also agree with others that technique does seem to count for something with this amp.
* The amp has a cool clean tone and good crunch tone for classic rock rhythm guitar. Forget about nu-metal.
* The amp will cut through a loud mix
* The amp seems to sounds cool with an overdrive pedal (I have a Boss SD-1)
* With its boutique price tag, the Flexi-50 should have a much better overdriven lead tone.

I have only owned it for two months. I appears to be very sturdy.

N/A

I have been playing for 30+ years.
I have owned or played several Mesas (no thanks), A silver face twin, a Peavey Classic 30 (great amp) and a vintage Traynor YBA-1 (near nirvana)
I would probably buy something else if this was stolen.

I purchased this amp new in the beginning of 2005. My intention was to find something a little more flexible that my Marshall JCM2000, which I have been playing for the last few years. There was not a dealer in my area at the time, so I bought this over the internet based on the rave reviews this amp has been getting. This is a single channel amplifer, but with quite a bit of control over that one channel: including foot-switchable Master Volume and Boost features, along with the usual EQ controls. This is an all-tube amplifier designed to allow the user to try different combinations of input and power tubes. I was particularly drawn to this amp because of this ability: to try out different tubes in order to fine tune my sound. This amp also has a feature which makes it easy for the user to adjust the bias of the power tubes. As for the single channel feature, the THD website describes using only the guitar volume for "cleaning up," the guitar signal. I did not find that practice to work particularly well for me. In retrospect, the THD statement about the different channels on multi-channel amps sounding "more or less the same" may be a bit self-serving, as THD only makes single channel amps at this time.

I play in a classic rock band. My primary guitars are a stock Les Paul Standard with "Burst-bucker" pickups, a Strat with Dimarzio "stacked" single-coils, and another Strat with Lace Holy Grail pickups. I would say that the lead guitar sound I shoot for the most runs along the lines of Journy/Boston/Santana/Mana, etc. It is in this capacity for lead guitar sounds that, in my opinion, this amps falls sadly short. I hate to say this. I really WANTED to love this amplifier -- after all, the reviews are great, so the amp must be awesome, right? Right out of the box, plugged into an Avatar Speakers 2X12 with vintage Celestians, this thing sounded horrible. I was trying to get a sweet, over-driven, boutique amp sound, but this amp was not about to give it. The distortion sounded fuzzy and synthetic, like cheap transistors. It seemed to have a lot of buzz to it, like a Marshall with the presence control pegged to maximum. Strangely, the initial pick attack to the strings was very loud and percussive, but the signal seemed to drop off faster than expected, as though a compressor was engaged at the time of sounding the initial note, but then disconnected as the string begins to vibrate. Reducing the "CUT" control helps minimize this, but not enough. I called the folks at THD; they felt that I would have much better performance if I incorporated a Hot Plate into the set-up. One 8-Ohm Hot Plate and $279.00 later, I tried it again, but the amp was not any better. The Hot Plate seemed to increase the hiss. Another phone call to THD, and I was swapping out the EL34s for 6L6's. Actually, this smoothed things out a bit, reducing some of the hiss when the Gain and Input Volume were at 3:00 O'Clock or better, but I still didn't think it sounded very good at all. If fact, my cheap practice amp, a VOX ADT30, sounded much, much better. More phone calls to THD resulted in Ed giving me some recommended control settings over the phone: while I very much appreciated his time, the amp still sounds very strange to my ears: a percussive intitial string signal, lack of sustain, and a tone rife with hiss (or should I say lack of tone?). I have now tried the amp through a different speaker cabinet, but this does nothing to improve the performance. There is now, since the time of my purchase, a THD dealer in my region. This dealer says that "this isn't a high-gain amplifier;" he recommends running the amp clean, and putting a high-quality overdrive pedal on the front end for that "harmonic distortion" lead guitar sound. That would probably work to some extent, but at this much money, I would expect this amp to sound a lot better without any effects. The best sound I have gotten out of it is a fairly clean blues sound (think SRV's clean stuff). By itself, I have not gotten this amp to give me the harmonic-distortion, violin-like sustain that I was hoping for. Maybe I got the lemon. I cannot account for the fabulous reviews this amp gets, unless these folks are just playing clean blues and jazz?

This amp has not broken on me. It appears to be very well made. I would gig with it if I liked the way it sounded.

The customer support, despite my problems with getting this amp to sound decent, has been wonderful. I have spoken directly with Ed and Andy up at THD, and I do very much appreciate their time even if the amp isn't working for me. On my last conversation with THD, however, they were kind of pushing me to try this thing through the THD speaker cabinet, and I have to say that I felt frustrated that the solution to the sound quality problem kept being to buy something else (tubes, Hot Plate, etc.) Still, these folks have been very generous and patient with me over the phone. I can't imagine being able to talk to an engineer over at Marshall, for instance!

My overall rating for this amp is very low because, fundamentally, I never got really good guitar sounds out of it. The name and description of this amp implied something much more versatile than it actually was, at least withn respect to the one I bought. I would like to close this review with some advice to others that may be thinking about buying one of these: First: buy it from somewhere that you can return it (Musiciansfriend, etc.). That way, if it really doesn't work for you, you can return it. Second: really assess your performance styles and determine if a single-channel amp is going to work for you. I think that a lot of rock music is far better suited to a channel switching amp. Third: forget the hype. Forget the reviews. Forget what I write here, and forget what the other guys wrote. Plug in your guitar find your sounds and play it. Close your eyes and listen, really listen. If it really works for you, then great! If not, then return it, and don't worry about being judged as a lesser player if you can't convince yourself to feel the same way as previous reviewers may have. After all, art is subjective. As for myself, I have found a much better solution with a Mesa Lonestar, but that will be a different review......

Visually the amp looks terrific -- watch those valves glow --E34's on this come as standard. It is pricey but offers a tonal pallete that sounds good to my ears. I was wary about gigging with this though as only a plastic cover is offered -- I'm sure some manufacturer will have a flightcase for it. I opted to buy the THD speaker enclosure as it's about the best reference monitor I've heard (I tried it with other heads). All the controls work well together but do take time to find that sweet spot. I like the idea of a single channel -- I've always found that most amp manufacturers compromise somewhere on their multi-channels -- either the clean or the dirty suffers. The ease to change valves makes this a good choice for the recording guitarist -- go brit or yank armed only with a multimeter. The provision of 20w or 50w is good too as this is seriously loud. It'd be nice to have a footswitich to bring in pedals in the loop -- too much footstomping for me.

The sound. First try in the shop, I sounded really messy. This amp takes no prisoners when it comes to sloppy technique. I immediately slowed down and tried to interact with it. This amp really does raise the bar --although I have found it needs an overdrive/distortion pedal to take it into this millenium's style of heavy tones. That's not a criticism -- it's just that it's hard to go from crystal clean to crunch to squeal. This amp does it all -- but it does require careful setting up and thinking ahead. I've found a Boss DS1 works well and a hotcake. This needs to be heard in a band environment because that's where it really cuts through like no other amp I've had. However, if you play sloppy -- this will exaggerate those errors. It might just help your technique!
I use a Fender Strat with duckbuckers and a JB along with a custom built guitar made many years ago by Ian Watt. For the first time I can really distinguish between the pickups.

Tubes look easy to replace and so far it's not broken down on me. I always take along a Boss GT6 I can plug into a PA if it fails -- doesn't supply the sound of the Flexi -- but it's a safe back up.

Before I bought this I harrangued the customer support people about availability of parts and servicing and they were very helpful.
I really must say they've responded each time to any queries -- no matter how stupid sounding.

I'd buy another if this was nicked (stolen) I love it's apparent simplicity -- it's about the guitar and how it interacts with the amp. For example my guitar sounded poor plugged into a Peavey Joe Satriani model -- but the Ibanez Satriani guitar sounded very good.
With the THD all the guitars sounded good. I tried Mesa Boogies -- Peaveys -- Marshalls and settled for this.

Taking into consideration that it is a single channel amp, it does have a good amount of features, but some of the features aren't really as useable as it first seems. For example, the footswitchable boost looks good on paper, but in reality, the volume difference is to great to be of any use. I would have liked to see the ability to switch only the input gain switch via foot (now, you can only switch it and the boost simultaniously). The amount of gain that the input gain switch adds is just the right ammount for lead boost.

This can be an incredible sounding amp, or nails on a black board, depending on the player and playing style. For those used to modeling amps, or all in one FX boxes, this amp may not suit your needs. It can sound immensly better than the modelers, but it takes more work to play (as with any real tube amp). Where on a modeler, you can pretty much hit the strings any way you want and still get the same sound, with the Flexi, dynamics play such a big part of it's tone that you actually have to play your instrument.

This is the third THD I've owned, and I've never had a problem with any of them.

I've heard great things about their support, but I haven't seen it first hand. I've tried e-mailing, and never got a response. I see that they are now selling to Musicians Friend. Perhaps the company is getting a little big for their employee base?

If you use real tube amps, and are looking for a single channel amp that sounds like what you think the best hot rodded plexi SHOULD sound like (but never does), then you'll be happy.

If you're playing a Pod or digital stomp box, move on. You won't like the amp, because it sounds and feels like a real life tube amp.