THD Flexi 50 Head

Awesome features on an otherwise simple amp! It's got an fx loop in back, a boost switch with included pedal. A bypassable master volume control. A bright switch. And a cut knob which basically functions almost as a presence control to help the amp cut through the mix. It also has switchable wattage from 20 to 50 watts which is useful for kind of taming the volume a tiny bit and smoothing out the crunch a bit as well. Overall, very simple to use but packed with useful features!!! (unlike some other more comlicated amps or digital modellers which have lots of 'features' but all of them basically sound the same).

Currently using the amp with an american deluxe strat with noiseless pickups. The amp can cover a wide range of styles. By itself you can easily get useful fender clean tones, crunch a la classic rock (think marshall plexi -- ac/dc, etc.) With a pedal in front (i.e, I throw in a tonebone hot british) and the amp set up clean I can easily get metal sounds similar to metallica ,etc. In other words what you want to dial in you can. For my speaker I am using one of two things. Since I am an apt. dweller volume is an issue. So I have the ampo either plugged into the demeter iso-cab with vintage 30 12" speaker located in my closet or I plug directly into a palmer pga-04 speaker simulator. With both devices I can get very cool tones straight to tape and for playing out (which I haven't done with the flexi yet) I can produce a predictable tone and just plug into the pa system.

looks great and built tough. I also own a thd univalve which I have had for the last year -- no problems yet.... Overall the customer service at thd is very good and if there are any problems I am sure they would take care of it!

I have dealt a few times with Ed DeGenaro and he's always been very courteous and informative and he answers his emails pretty promptly. He was the one who convinced me to check out the demeter iso-cab which his company obviously doesn't make. Very good advice and help.

This amp is awesome! Just for references I also own a fender deluxe reverb reissue, a fender hot rod deluxe, the univalve and a yamaha dg-stomp which is currently in the closet. All of my amps sound good but there is something special about the flexi 50. It can generate great clean tones and fantastic solo tones and it does 'play well' with other devices like my pedals. Overall a great amp purchase and one that I plan to use and keep forever!!!

This is a brand new amp from THD, but is a very different sound from their Univalve and Bivalve amps. I like the previous reviewer's idea that this is like having a nice plexi AND a nice Super Lead...and would add that it's in a smaller box!

This has some very interesting and well considered features: Lo/Hi input gain, bright switch, a GREAT eq section (hi/mid/lo), Boost gain and tone controls, master volume, and cut (as in "through the mix") control, external bias points, loop, line out, and footswitch to turn boost and master on/off. The input gain can also be activated with the boost, 20/50 watt switch (changes plate voltage from 325 to 475).

Although the stock tube set is pretty loud, there are many tubes that can be used in this amp, making it work nicely for gigs and home (when nobody's there) use. I could see this being great in the studio as well, although I've not yet had the opportunity.

It sounds unbelievable. If you like Marshall tones, get one. No hype, this is the first time in ages that I've been this happy.

I've found this amp to work WELL with every guitar (Strats, Tele, Gibson/humbucker-type), pedal (TIM, Tonebone, Barber, Prescription, Fulltone, etc), and cabinet I have...

I've recently done a little experimenting with tubes and have found that NOS Visseaux 6K6 and 6V6 GTs work well at bringing the volume down without losing the tone...I hope to find some current production replacements for these in the coming months...

I owned a Univalve and traded up to a Bivalve...been using their stuff for two years...never a problem. Looking inside, I can see why...it's all heavy duty.

I know it sounds suspicious that I'm this fired up about one company, but peruse the web a bit (esp univalve.net), and you'll see why I say THD is the best...not only do they make superb products, but they really go out of their way to make customers happy...it's how all businesses should be.

In 20 years, I don't think I've been this inspired by a piece of gear...I'm afraid that my Bivalve and Marshall will never get used now! If it disappeared, I'd definitely buy another immediately. I had come to the decision that it was between the Flexi and a Dr Z (Maz 38 or Route 66). The latter are very fine sounding amps, but don't hold a candle to the Flexi when it comes to number and usefulness of features. Ultimately, I'd have bought this anyway, without the features, just because the basic tone of the amp is exactly what I wanted...

This is the newest THD Amp the Flexi 50 (Serial #015). It is a 50 watt A/B amp. It has tons of features from the 20 Watt Mode to 50 Watt Mode; Master Volume or no Master Volume; a very robust foot-switchable boost and overdrive section; FX Loop; Can use just about any tube and built-in bias adjustments. It is one channel but the unique boost section can dramatically change the amps tone which will give the impression of a multi channel amp. This is definitely not like the UV or BV. It is a stage performing amp that can also be used in a house. Make no mistake about it this amp can easily compete with a 100 watt Marshall in the volume category.

I use everything from Les Pauls and SGs to Strats to Teles. ALL guitars sound GREAT in through this amp. All of the different guitars I have used have retained their natural tonal traits. A Strat sounds like a Strat and a Les Paul sounds like a Les Paul etc...

This amp is based on a Marshall Plexi. When shopping around I tried a couple of the Plexi based Amps and while they were good they were all 1 trick ponies. The Flexi on the other hand sounds like the best Plexi you have ever played and then when you activate the boost it can sound like the best 100 watt Super lead you ever played. I am a long time Vintage Marshall user (over 20 years)and I never thought I would get an amp that completely blew away my old Marshalls but this is the one. It is the tone I have heard in my head for a long time. One of the first things you notice is that all of the notes have extreme clarity. I find that even the best Marshalls get muddy playing above the 12th fret on the E A and D Strings. This amp is so clear when playing in that position it is remarkable. This amp is also very sensitive to your guitars Volume and tone knobs. In regular mode with no boost you can easily lower the guitar's volume knob and the amp cleans up nicely. With the boost on you could easily play the raunchiest of guitar parts. I play Hard Rock and Metal and this amp does those tones with Warmth Clarity and POWER.
I would give it an 11 for sound if the drop down would let me.

It is built like alll THD amps. This amp is as sturdy as they come. HAs the THD Metal Cage like the UV and BV and is HEAVY. Components are all top notch from the Footswitch to the cable for the footswitch to the amp itself... Sturdy

THD is legendary for their awesome support. I have needed support from THD in the past and they are nothing short of GREAT in this area. Comes with a 2 year transferable warranty.

In all my years of playing this is the best amp I have ever owned. I still have my early 70s super leads but they haven't been getting much use since the Flexi showed up.... If this were stolen I would have to take a trip to Seattle and beg Andy and Ed for another immediately. Consider that it is about $500-$700 cheaper than one of the Plexi one trick pony amps and the Flexi is a remarkable bargain.