THD Yellowjackets YJSD

I bought two sets of these last week. I had some spare cash and decided to try 'em in my JCM 800. I had to email THD to make sure I got the correct ones for my amp and asked them the physical height as the is only about 5 and a half inches of room in the JCM's head cab. I received a prompt reply the next day sayin' they will fit no problems as they are only about 5" high.

Giving them 5 in this category coz there's really no features and 5 is a pretty neutral number

Hmmm.. sound "quality" is a subjective thing. I'll start by sayin' straight up, I don't like 'em at all. They sound way too thin, and have a nasty fizziness in the top end. I understand why they are called "yellow jackets" now. Its coz they buzz like a yellow jacket wasp. Not a nice sound.

I dig the tone of EL84's in my Mesa Boogie and various other EL84 amps I've mic'd (was a live sound engineer for about 7 years) but they just don't work in the JCM800.

The only way I can get anywhere near a pleasant, usable sound is to run the preamp gain way down and not turn the master up past about 10 o'clock or they overdrive too much and sound nasty.

Dunno about reliability as I've only owned 'em for a week. They do get very very hot and develop a hot "smell". The "smell" ya get from electronic equipment right before smoke comes out. I don't trust 'em so I've left the back off my amp so I can keep an eye on 'em.

Like I said earlier, I got a prompt reply from Ed at THD both times I emailed them.

The second time I emailed was the morning the YJ's arrived. One pair was soldered perfectly on the pins but the other pair had several "empty" pins that contained no solder. Ed assured me the lack of solder in the pins would not affect them in any way.

Anyway customer service has been fine so far

One other thing that bothered me about the YJ's apart from the lack of solder in the pins was the way they have been assembled. The yellow tube that contains all the electronics is glued into the tube base. All bar one have been glued in crooked. One is so bad it looks like the leaning tower of pisa!
Not that ya can see 'em when they're hidden away in the back of the amp..but surely it would not have been a difficult task to glue 'em in straight. They charge a premium price for these things, so I want a premium product. Fair?

Anyway overall I'm pretty disappointed. I'll keep 'em for a while and see if they grow on me, but I doubt it.

They don't have any other features than having the ability to block the amp's grid bias voltage so you can run a pair of EL-84 with a pair of 6L6s at the same time without any modification to your amp.They will change your amp from A/B class to single Class A operation.They will reduce your amp's power so it will distort earlier at lower volumes.They will give your amp the classic Brittish sound in just a second.Enough features for me.MAKE SURE YOU BUY THE SHORT ONES IF YOU DON'T HAVE PLENTY OF ROOM INSIDE THE POWER TUBES SECTION.EL-84 TUBES ARE INCLUDED IN THE PACKAGE.

I have a JSX head wich is great and full of features.You can use either 6l6s or EL-34 with it.The amp comes with the EL-34s from factory.The Ultra channel is just amazing with a very modern sound and power.The Crunch channel is more like a Vintage/Marshall thing but honestly,alone it will never going to sound like a true Marshall.(Anyway is a Peavey not a Marshall).I was trying to have an amp which deliver the Modern/Mesa sound at one side and the Brittish/Marshall thing at the other.I changed the power tubes to 6l6s looking for the best of both worlds.I ended up having a more 5150/Laney sound.Now the Crunch had more power and less Vintage sound and the Ultra was a true Diezel/Krank thing.I put two Yellow Jackets in the middle position and left the 6l6s at the corners.What I have right now is just an amazing sounding amp wich plenty of power,but with a smoother distortion,tons of clarity and that Vintage Vox/Marshall middy sound at the Crunch channel.The Ultra now is just perfect.More like a Mesa Mark 4 in steroids.Very compressed sound.Cristal Clear cleans and highs and a lot less hum from the amp.Now the amp is so quiet that it's hard to know when it is on.I had to re-adjust all my settings in order to go for my sound.Now I'm using a lot less bass,mids and highs.The amp will distort at very low volumes.It's like having a new amp at home.I'm using it with a Music Man Axis all stock and a Fender Floyd Rose Stratocaster with a Dimarzio Super 3 i the bridge,an YJM in the middle and a Virtual Vintage Solo Proin the neck.I play mostly 80's Metal.

I don't know how much will they last?

This is what make me buy the Jackets.THD's Customer Service is just amazingly fantastic!! I did e-mail them about 5 times before I placed the order.Asking them all kind of questions.Their answers to my e-mails where very fast.They told me they love to answer questions.They are very good selling their image.

I've playing now for 7 years.I have an all rosewood Music Man Axis,a Fender Floyd Rose Strat with Dimarzios.I have a JSX head witha Custom Made Cab loaded with 2 Celestion Vintage 30s and two Enminence The Governor.I do have a Boss ME-50 and a Boss Noise Gate.
That's it.I'll buy the Jackets again if they were stolen.They are an inexpensive way to upgrade your sound without hurting your amp.If you don't have the money to buy a boutique amp,this is the closet you can get with a lot less.

The one prime purpose of the THD Yellowjackets is to give one the ability to reduce the power output of their tube amplifier. The amount of power reduction will be dependant on the original output of their tube amp. THD cites the reduced output as about 20 watts. That being the case , your 40 watt amp will be rduced by 20 watts. Your 60 watt amp by 40 watts etc. All of this under the assumption that you have a 2-tube output stage, 2 x 6L6, 2 x EL34, etc. If you have for example amplifier using 4 output tubes, commonly with an output of about 100 watts(more or less) than the THD Yellowjackets offer even more opportunities for custom power reduction AND sound shaping. You can use just 1-pair of yellowjackets and have a 20 watter. Use 1-pair of yellowjackets AND 1-pair of the original output tubes, and you have an amp with approximately 70 watts. But, more importantly in my opinion, you now have warmth in your tone from the relatively early breakup of the EL-84's in the yellowjackets, PLUS a solid clean BACKBONE to that warmth in the shimmering cleaness of your 6L6's or EL-34's. Using an amp which switches 2 power tubes out of the circuit for 1/2 power, you can carry your amp to an unknown job with unforseeable power requirements several sets of differing tubed, several pairs of yellowjackets and tailor your sound to the situation, acoustics etc. With a certain amplifier I own with 4-output tubes, I have had cause to use all of the following combinations: 1-pair Yellowjackets, about 20 watts: 2-pair Yellowjackets, 1-set with early breakup EL-84's, the other set with mid breakup EL-84's, about 40-watts;1 -pair Yellowjackets, 1-pair if 6V6's, still only about 40-watts but the 6V6's giving some 'BACKBONE' to the tone. 1-pair Yellowjackets, 1-pair 6L6's (early breakup pair so as not to overwhelm the EL-84's in the Yellowjackets.) This may seem like a long way around to describe as features..but believe me if you are patient, have a fair supply of tubes of varying current draw on hand you can make on the spot quick changes to suit your particular playing situation.

MY particular guitar,pickup types are secondary, but I usually use single-coil Strats with some custom wiring,. The point of my reveiew was to advise people that they are able to tailor their sound to DIFFERING guitar/pickup choices and musical syles with this product.But,,since asked I play blues,country, classic 50's rock as well as what came in the mid 60's when I started playing. What kind of sounds can it get?? Here's the kicker! I've read many reviews where people were either mildly dissappointed or totally bummed-out(hey that dated me didn't it?!) by the sound they got from their (for example) Fender Hot Rod Deluxe.On the other hand some were delighted. Although of course tone IS SUBJECTIVE and tastes very personal, it seemed to me that MOST of these people were descibing the tone they sought in remarkably similar fashion. THE KEY. Repeat THE KEY, to use of the Yellowjackets with EL-84 tubes is to REMEMBER you're STILL DEALING WITH TUBES! The Yellowjackets merely hold them in place and limit current to about 20-watts a pair. Your 'breakup point',;tube saturation', distortion etc. is still dependent on the tubes you put in the Yellowjackets. I use JJ/Tesla EL-84's, but THAT IS NOT WHAT I'M REFERING TO! Whatever brand you favor/choose you need to buy at least 3-pairs! 1-pair of 'early breakup', 1-pair of 'middle breakup', and 1-pair of 'late breakup' tubes. You then try them one after another in your amplifier for headroom, or early breakup, whatever YOU are seeking.And I found that in MY Hot Rod Deluxe, the mid breakup tubes were best OVERALL choice, for most places. At a Country venue I play the late breakup tubes were entirely too loud before any warmth from tube breakup. The middle ones were perfect for THAT venue. Another place I hurriedly switched to the esrly breakup tubes. There really IS A HUGE DIFFERENCE!I think this is the solution to the disappointment and disallusion I read in some revues. Oh, by the way, In my HRD, I placed an Electro-Harmonix 12AX7 in V1, a JJ/Tesla 12DW7(ecc-832) in V2, and a JJ/Tesla 12AX7(ecc-83s) in V3, the phase inverter position. The 12DW7(ecc-832) is a split performance tube. The (A) side performs at 100% of a regular 12AX7, and runs the reverb. The (B)side which adds gain when the "Gain Channel" is switched in operates at only 20% of regular 12AX& output. This reigns in the frequently wild, uncontrollable and overly gritty gain of the HRD gain channel. With this set up I set the master volume at the same level as clean volume, and run the gain between 2 and 4. This gives just a srep up in gain in the switched position, Hitting the more gain swithch now gives a creamy smooth USABLE distortion. By the way This Preamp tube set-up (mainly the substitution of the 12DW7 for the 23AX& ib the V2 position) REALLY makes a difference when you need to switch back to 6L6's for some serious volume and headroom, as well. In Traynor YCV40. the early breakup tubes work best (for me). In Mesa DC-50, early breakup worked best for me as well..with the following change in preamp tube lineup in order to adopt the second channel to my musical tastes. V1, Electro-Harmonix 12AX7, V2, JJ/ 12DW7(ecc-832}; V3, JJ/ 12DW7(ecc-832); V4,V5, & V6, JJ/ 12AX7(ecc-83s). Brings the two channels into close equality in volume, which makes setup MUCH EASIER. Notes on channel 2, now well defined. Crunchy chords now possible with definition, but a creamy sustain still very easy to ontain. Mid(boinky)sound now can be dialed out. By the way, works with original 6L6 power tubes in place as well. My Fender 'Pro-Series' "Concert Reverb" 50-watter loves the LATE breakup EL-84's in HER Yellowjackets. Marshall JCM 800, favored the mixed blend, of early AND late breakup EL-84's in her Yellowjackets. I got another amp using 4-power tubes but, I'm NOT gonna tell you what it is! 'Cause I want to get another one cheap first. It has become my absolute most convenient, versatile carry anywhere, practice to festival amplifier. Whether running Yellowjackets in all 4-slots or 1-pair of Yellowjackets and a pair of 6V6's (or 6L6's) she's ready now for anu continguency. If you are unhappy with your results with Yellowjackets...try what I've outlined above. If you're STILL unsatisfied..sell 'em to me CHEAP. All my amplifiers are DEMANDING that they have their own personal sets to carry around with them and not have to borrow and swap with the other amps. Amps get VERY JEALOUS, you know!Pick a sound you can get it.

We are talking about the most fundamental/basic of electrical components here. A male tube insert coupled to a female tube-socket with , (what?) a resistor between to control voltage. Unless THD receives a bas batch of defective components they're gonna work!Tubes? Well..Tubes ARE tubes. They're gonna wear out. If bumped too hard they'll break. Running Class A they need replacement more frequently than tubes run A/B..PLUS you're gonna play so much more now that you have a decent sound at bearable volumes, you're gonna burn out tubes that much quicker! Hey! You're really not gonna mind that much!No problems with product yet.

To date I've had no need for repair or contact after purchase. Prior to purchase of my first pair I did E-mail THD to ask question about correct type tp purchase for a particular amp. Went about my business (reading reviews on Harmony Central, of course!) Well' before I had finished (Hey! Some of you guys are as long winded as Me!) I had my answering E-mail from THD. And from the head man himself. I believe that qualifies as helpful AND friendly. You know I've forgotten the warranty period..but I believe that were it expired they probably would/could fix for a trifling fee. Also, I believe if worse came to worse I could do it myself.due to my forgetfulness AND lack of need will give them benefit of doubt.

This coming December I'll Have been playiing 40-years, minus some times when I gave up and quit entirely, selling all my equiptment!What equiptment do I have? Lots of guitars and TUBE amps! Thats where I'm gonna leave it,cause if I list what I have NOW, I'll start mentally comparing to what I once had and a deep near-suicidal depression may descend! I love what the product does! Wish I'd have had them 35-years ago when I started showing some proficiency on guitar.Hate nothing about them. Compared to the 'Groove Tubes' equivalent, but could not find many outlets selling..so cost became an issue. I frankly don't know..the Groove Tubes' version may be just as good, BUT I did read some reviews citing trouble with them.Is there anything I widh they had? Actually, yes there are 3, things I think would improve them. I have modified mine to reflect 2 of these improvements(which I don't even think would void any warranty) My 3-rd idea WOULD require R.& D. and more expertise than I have! I'm thinking about contacting THD about all 3.....Well I.ve tried to avoid hyperboyle and just tell you folks how I used them, AND more importantly HOW I made them usable for me. I truly believe that some of the folks who were not well pleased with their experience with Yellowjackets, might truly find the sound they were earnestly seeking and hoping for had they just conducted a controlled experiment in tube swapping. In other words don't just call brand X tube crap and buy another brand. Buy 3-sets of one brand ,EACH with different breakup points THEN try the tone-test. Once you find what you want, i.e.headroom/clean versus breakup, if such and such a brand tube is not bright enough or too bright or dull sounding or lacking bass, THEN buy another brand in the breakup range you found closest to your ideal.That could get expensive you say? Well, not as expensive as getting rid of that multiple /hundred or thousands of dollars amp because you wouldn't spend a hundred bucks for 4 or 5 sets of EL-84's! Not to mention what would become the wasted expenditure of the price for the Yellowjackets. A little trial and error, alittle patience, and a relatively small additional exprnditure will reap a rich TONE REWARD! And NO..I don't have stock in any of the tube manufacturers, importers or retailers, nor do I work for amy of them! Chuckle!!

Bought these for my '89 Marshall JCM 800 2210 (100 watt channel switching amp). These amps are brutally loud, and on the bright side (trebley)due to the EL34's. But they have great gain, and come on, it's a Marshall! I use this amp for venues from 50 people to 2,000 people. The Yellow Jackets knocked it down from 100 Watts to what they claim is 20 Watts. But let me tell you, this is one loud 20 Watts! I can use this for the largest of venues and have plenty of volume. I play loud live, and this still has more than enough volume. Just pull out all the EL34 tubes, and put these 2 EL84 Yellow Jackets in Powertube slots 2 and 3. You can add the EL34's to slots 1 and 4, but I have no need to do that, and don't see myself having to.

I use this with a Jackson USA custom, Duncan JKB in bridge and 59 in neck. My style is 80's hair metal (Nuno, Lynch, Vito, etc.). These My complete setup includes rack mounted tuner, G Major, BBE Sonic Maximizer, HUSH, and wireless system. The Yellow Jackets changed my sound and got me EXACTLY what I wanted. More mids and punch, and more crunch! I have searched forever for this tone, and I am just floored at how great they sound. I have tried Mesa Dual Rec, POD, and ADA MP-1, and none of them touch this sound. I can back off the volume to clean it up some, and of course channel switch for clean (well, it is a Marshall, so sort of clean!) I use a MicroAmp pedal for extra gain during the solos, but no more! Don't need it now....this amp screams!

THD is known for awesome products and great customer service, so I expect no problems there. I understand these tubes get quite hot, so I will keep my eye on that...

Great customer support, and they will even walk you through the process of installing (should you need it), but it is a brainless install, so it should be easy. Regardless, you can even contact them to find out if it will work with your amp. Great people, great products.

I have been playing 20 years +, and have tried allot, I mean allot, of gear. This simple addition at such a great price is, in my book, an absolute must for any guitar player. The Marshall is just so loud, this cuts the volume, and adds more crunch. I can pinch harmonic till the cows come home! Great product, cheap price, and huge tone change. I highly recommend this product. It is a must have for any serious player.

Easy, just plug in and play. Plugged them into a Fender super twin reverb. They set down the effekt by 50 to 70 percent and made a class AB amp into a class A. The result is fantastic. I play blues and blues based rock'n'roll and want that 70:s sound, these yackets got it for me! Set a 9 because they do just what their advertised to do.

The sound is amazing. Before modification the Super twin was just as any standard fender amp, very loud and with nice and hard clean but no distortion at all. After modification the sound change to that 70:s sound, varm and brittle with a nice varm distortion if cranced to 10 on the master and all eq knobs (i use this setting to allmost all sound that i desire. Adjust the sound with the volume and tone controlls on the guitar). With my 79 strat i can get that brittle and watery sound that i never reached before, just set the treble and middle to 6 and the bas to 3 and it rings. With my new Ibanez artist ar 300 i reach the nice varm and dirty distortin that i never found before. The best thing about this modification is that it allows you to control the sound with the volume knob on the guitar. Full trottle on the guitar and there is that god distortion, about half trottle and there is that god cleane. The effekt in this amp is 180 watts with all six 6L6:s, now with two yellow yackets its about 30 - 40 watts but that is class A watts and sounds like 60 class AB watts. So, nowadays i'll never say `what` if someone ask me anything the day after a rehearsal. I set a 10 because now its the best sounding amp i`ll ever owned.

So far no problems but its only after a few weeks. I set a 5 because the lack of time used.

I have nothing to say here because i have not been in contact with THD directly. The warranty is one year. I set a 5 because of the one year warranty.

I've been playing since the mid seventies and owned a marshall 100, a vox ac30, an ibanez 50 watts solid state amp, several twin reverbs among all other amps. And now a peavey bandit 65 (bedroom amp) beside the super twin rewrb. If they (it) where stolen i do buy a new pair of yellow yackets and install them into a new twin. I love the sound of vintage amp that i get with these yackets. Even the vox ac30 i owned in the late seventies sounded less vintage! Go buy it, its a better way to vintage sound than a amp at a cost of thousands of dollars.

TUBE CONVERTERS FROM 6L6 TO EL84'S

MY WIFE BOUGHT THESE FOR ME FOR CHRISTMAS TO PUT IN MY BLUES DEVILLE, CUZ I COULDNT AFFORD A VOX AND I AM REALLY FOND OF THE EL84 SOUND. I PLAY A FENDER STRAT. I ACUALLY REALLY LIKED THE SOUND OF THESE, BUT AFTER 1 WEEK ONE OF THEM STARTED OVERHEATING AND HAD TO BE SENT BACK TO THE COMPANY. THE SECOND ONE I GOT EVENTUALLY DID THE SAME THING, SO I HAVE BENN RUNNING ONLY ONE YELLOWJACKET, WHICH SEEMS TO WORK OK.

I WOULD NOT BUY THESE AGAIN, DUE TO ALL THE PROBLEMS OF HAVING TO SEND THEM BACK TO THE COMPANY. THEY DO SOUND AWESOME, EVEN VOX LIKE.
SINCE IT IS A NEW TECHNOLOGY MORE STUDY SHOULD BE DONE TO SEE IF SOME AMPS ARE NOT COMPATIBLE.

CUSTOMER SERVICE WAS GREAT, SENT ME NEW ONES FREE OF CHARGE.

I WOULD NOT BUY THESE AGAIN, NOT UNTIL I COULD BE SURE OF THEM WORKING ALL THE TIME. I ALLWAYS KEEP THE ORIGINAL 6L6'S JUST IN CASE.
I PLAY A WIDE VARIETY OF MUSIC FROM POP PUNK TO WORSHIP AND INDIE ROCK. I ALSO USE A LINE 6 DELAY, TUBE SCREAMER, MXR DISTORTION, SMALL STONE PHASER.

These are the YJSD type that reduce power as well as conver to EL-84.

Convert just about any amp using A/B class power with EL-34, 6L6, 6V6 or 6550 tubes to A class EL-84's

I used them in a vintage Marshall JCM 800 2203 100 watt head

No opinion on the rating because it doesn't really apply

Nice and sweet, warm tube distortion at lower levels, added more midrange, chime and warmth. I used the 2203 with the THD's in it with a Marshall 1960A 4x12. These really altered the characteristics of the amp, still retained the "Marshall" tone but not quit as brittle sounding and very musical. I had to back off the mids a bit on the amps EQ. Nice sounding. Even at 20-25 watts the 2203 was still plenty loud through a 4x12.

N/A brand new

Very good customer service. I had some questions before I purchased them and they were great in answering them.

I play hard rock and metal, used a Jackson USA Strat with a JB in the bridge and a little 59'er in the neck.

These did exactly what I bought them for. Installation was easy and THD includes a set of instructions for installing them and the different options you have for a 100 Watt amp. For example you can replace all 4 power tubes and install Yellow Jackets in all 4 slots. You can remove all 4 tubes and install Yellow Jackets in the middle 2 tube sockets and leave the outer two empty (what I did) or you can use the Yellow Jackets in the middle 2 tube sockets and leave in your existing tubes in the outer 2 tube sockets giving you the best of both worlds (I haven't tried this as of yet)

If you are wanting to give your amp a different sound or tone for little money these Yellow Jackets are the answer. If you don't like the sound of EL-84's they may not be for you. The good thing about this type of Mod is it is reversible and requires no bias adjustments going back and forth.

This is a simple tweak you can do to almost any tube amp.
Remove existing power tubes and insert the YellowJacket adapters and then insert the new EL84 power tubes into adapters. Power-up and go-for-it.

I have my YellowJackets in a Hot Rod Deville 212. Set Drive to 7 and master volume on 9. With my les Paul the sound is thick and nasaly and really puts a grin on my face. I also tamed the volume with a THD Hot Plate. The EL84's are much smoother than the stock 6L6's. I love the tone when cranked-up loud. These adapters also cut the watts just about in half but the amp is still plenty loud with 30 watts.

So far so good, no problems at all.

No experience yet with customer support.

Fantastic product. Turned an alright amp into a seriously aggressive tone machine that really screams.

see post below

I've now had them for a month.

I have now had the chance to record with them and they sound fantastic. If you want to hear a short soundclip, e-mail me and I will e-mail it to you.

Apparently, not all amps like them, but the Peavey sure does.

I tried putting 2 of the 4 power tubes back in, and actually think it sounds best with just the 2 Yellow Jackets.

I will never go back to the Stock configuration as long as I own this amp.

Not had any problems in a month.

They are fantastic. Will answer all your questions.

Easy to install.

Installed on a Peavy Triple XXX. Made the clean channel sound fuller and bluesy with everything on 10. Chords seem fuller, rounder, warmer, and more pleasant than in stock config.

The crunch channel has lost a little edge in exchange for a smoother distortion tone....but very useable and very good. It did not change the character of the amp substantially. The bottom end is still there...which some have reported was lost. When I say the crunch channel has lost some edge, it sounds very good, just a hair different. I would think with a little e.q., you could get right back to the original sound. Plus, these majorly reduced the overall volume of the amp as advertised, and the slight loss of grit is a fair trade off for being able to run the thing at a higher power amp setting. At full volume with the yellow jackets, I am getting about the same volume I get at 3 in stock config.

I have yet to try these with two of the power tubes put back in (ie. 2 yellow jackets and 2 power tubes) Right now I am just running the two yellow jackets.

The Ultra channel has always sounded muddy to me, and it smoothed out the Ultra channel as well.

Let me put it this way, I don't know that I will ever go back to stock, and I have only had a chance to play with these for about a half hour, that is how satisfied I am. (I just put them in last night)

I can see where these would really make a Fender sound GOOD, because they do change the tone towards a warmer richer sound.

The Peavy is sort of a mix between a Triple Rectifier and a Marshall.
I think it has a better lead tone than most people get out of a Marshall and a way better tone than most get out of a Triple Rec. I will admit that with a really good Marshall, you will get a better lead tone (but you will spend a lot more money getting there) The Peavy can chug chug chug, like a Rectifier, but not exactly. It isn't everyone's cup of tea.

But assuming, you take the stock sound of this amp, and then install these, I think you would be really happy. And at least for 99.00, they are worth the risk of trying.

I have had such good success with these in this amp, I would really like to try them in a Marshall, a 5150, and a Mesa, to see what they would do.

The biggest change seems to be in the clean channel, and I would leave these in just for the change in the clean channel alone.

It doesn't sound like a Vox AC30, and it doesn't sound like a Fender Hot Rod Deville, but comparing the new sound with stock, it is much better.

I realize all of these things are subjective, but I have had this amp for four years, and have never been happier with it.

The flip side is, that if you try it and don't like it, it will take all of about 2 mintues to go back to stock and you haven't spent a fortune to try it.

I would consider these one of the top 5 guitar related purchases I have made in the last 20 years...how's that.

Seem to work fine.

I e-mailed THD asking which version I should get for this Amp and they e-mailed me back in less than an hour.

I don't give them a 10, because nothing is perfect, but they work just as adverstised and it isn't hype. I can really see where they would make some amps sound way better. I could also see where if you have found your "perfect" tone, they might upset your balance...but I was surprised that they didn't really change the amp as much as I expected (from a tone standpoint).

The ability to run the amp at low volume is a huge plus and they have made the clean channel so much better, I will take the slight loss on the crunch channel.

Simple tube swapping devices, really easy to install.

ESP with SD designed stock HB pickups. I put these in a Peavy Triple X. It took about 4 minutes to take the back cover off, pull the four 6L6 tubes and put the two yellow jackets in place. The center pin has a small tab at 12:00 oclock, and at first I couldn't get them to seat, until I realized you had to turn them to get the tab to line up with the groove in the recepticle. I've never changed a tube in my life, so, this may be old hat to everone else. I had to stop for a minute and look at the tubes I pulled, because at first I thought I had gotten the wrong one's, but then I noticed the little tab....no problem after that. If it hadn't been for that, you could install these in less than 2 minutes. These are the shorty version of the yellow jackets and they fit fine. I still have about 3/4's of an inch of space above the tubes so the long ones might be a tight fit or might not fit at all.

For about 5 minutes, when I first turned them on, they gave off that burnt/blown tube smell, but after that, no issues or problems.

Now for the sounds...

I was concerned after reading other reviews here before I bought them that they might not sound good in a high gain amp, as reports have been that they really sound good in some amps and not so good in others.

I was pleasently surprised. The clean channel sounds warmer and thicker and I can turn the master volume to 10 without ear splitting volume. With everything at 10, the clean channel has taken on a little bit of a bluesy tone. The Triple X is known for a very clean clean channel. The change in tone is very acceptable. Chords sound better and single note runs sound way better than before.

The crunch channel has lost a little "grit", but it has been exchanged for a smoother tone, which is very nice. In the original configuration, if you get the crunch channel where you want it and then back off the gain, you get kind of a crappy overdrive sound. With the yellow jackets, when you back off the gain, it gives you a nice overdrive sound that is better than stock. I did not lose the bottom end with this amp, as some have reported with others.

I have never been a fan of the "ultra" channel and don't use it much.
These things seem to have improved it and I am going to experiment with it more.

If I were to have two amps side by side, one configured with yellow jackets and one stock, I would take the yellow jacket model.

I think with a little e.q. you could get the grit back that is lost.
Let me be clear though, they sound really good.

It does what it suppose to do.

I installed a pair in two of my amps. A 70's Fender Vibrolux and a 90's Fender Super-Amp. I owen Strats, Teles, Les Pauls, 335s and been playing for about 30 years.
The Vibrolux did not sound good with the Yellowjackets, I did not like any of my guitars through it, It broke-up very early and had no headroom at all. I took them out and put them in the 60W 2 channel Fender Super. Well, this amp came alive, it's overdrive channel has doubled the dirt and now I get that "almost feedback" tone when I need it. The clean channel still has good headroom and had goten somewhat brighter, (great for a Strat with a TubeScreamer). I thought of getting a new amp before installing the Yellowjackets, but now I'm a happy Blues player.

4 weeks, So far so good.

i called them once before I got the product, they were very helpful.

It will not turn your Fender into a Vox, but if you need more drive out of your amp the Yellowjackets will do it, and will give your amp an edgier sound. I did not notice a segnificant drop in volume, I know that class A is louder than A/B, that may be the reason. They were well worth the $100, I'm not looking for a new amp (for now).

they're fine, easy to use and do what they're supposed to.

i couldn't agree more with bob the fireman before me.
first i had a similar product called "tonebones" distributed by rubytubes and i didn't like them at all. so i thought "well, maybe i should try the thd's instead" - but just like the tonebones, they turned any 6L6-amp i tried them in into a whimpy-sounding i dunno what. they did sound quite good in my '72 50watt marshall w/4x12" - perhaps because the el84's are closer in tone to the original el34's and the HUGE bottom made up for the whimpy sound. but they still left me with no headroom/dynamics at all.
these are my observations in full band scenario - if you're using them at home or in the studio, i'm sure they'll sound nice and beefy.

no problems here

they were "incredibly and helpful"

playing for 20 years. own loads of amps and stuff. the description seemed intriguing but they didn't do it for me tonewise. they're not a bad product at all and they do what they're supposed to (mainly lower your amp's output), but i wasn't happy with nothing but a thin, flat overdriven tone all night.

I put these in two amps. An early 70s Fender Vibrolux and a mid 90s Fender Super Amp. The Vibrolux did not like them, it broke-up too soon when plaid with a LesPaul, did not sound good on "10" and did not have enough gig volume. However, the Super amp just loves them. The clean channel has enough headroom and sounds as good as it does with the original 6L6s. The overdrive channel got twice as hot and produced the sweetest sound this amp has ever known. I highly recommend it.

don't know yet.

Two converters that takes your class A/B amp to Class A and uses EL84s instead of your EL34/6L6/6V6/etc. your amp originally came with. With the plug in and play design, this makes installation a snap.

Not particularly versatile and will definitely drop the volume and output of your amp. (at least for me it did) As advertised, this takes a 50 watt amp down to about 20 watts and is supposed to offer a voxy-type vibe to your amps sound.

After playing through several Class A amps and nearly buying (and still wishing I had done so) a Vox AC-15, I was excited about getting these converters, as many reviews suggest a positive experience in sound from their existing amp. I also usually like the sound of EL84 amps, and thought this would be a win/win situation for me. I could have the EL84/Class A sound with the features of my amp. Well, I have to say, I was a bit dissappointed. It dropped the volume alright (which was no big deal) but it created a buzzy sound, lots of hiss and seemed to make my amp sound processed. I compair the sound from the yellow jackets to that similar to a cheesy Digitech Valve F/X I had in the 90s. Needless to say, after trying to sleep on it for several weeks and then trying to adjust to the sound and have an acquired taste, I replaced my good 'ol EL84s and now enjoy the smooth, clear punchy sound the original tubes provide. The old saying "if it's not broke, don't fix it" really rings true here. At least for me anyway.

Overall, I was not impressed with the sound and was sorry I spent $100.00 (plus an additional $20.00 on better EL84s) and will probably sell them on ebay. To sum it up, they didn't sound completely terrible, but they won't turn water into wine either.

Seem well built and I understand THD has a reputation for high-quality components. Despite the unpleasant sound, they are constructed nicely and work every time I use them.

Never had to use them, but also hear they are great. I won't comment as I've had no personal dealings with them, but if you look at the reviews here, the webpages describing their products and just about anything else with THD on it, you will see these guys are top notch.

I've been playing long enough to know what I like. (20 years) Just because I don't like these (at all!) doesn't mean you won't. I'm just telling you as I hear it. No, I didn't go to Guitar Center and play through it for 10 minutes and determine these aren't for me. I actually own them and have tried to let them grow on me for quite some time. I have a variety of guitars (strats, teles, les pauls, 335s) and feel I made a qualified judgement on the different guitars I've used with the amp tweaks on a very versatile amp (Rivera). I'm not an expert in sonic technology and don't profess to be. I will say, be careful of the hype and don't settle for anything until you try it for yourself. I, personally, don't care for THD amp head either, which puts me in a small minority. I'm sure it's the tubes sent with the amps, but my life is too short to have to try thousands of dollars in tubes for something to sound good. I like to plug it in and go. Tweaking is fun, and I thought these jackets would be a fun way to get a different sound out of my amp, but I think I've learned my lesson. If I want a Class A sound (and a specific one at that) I will go out and buy a specific Class A amp and leave my great sounding Rivera alone!

Again, I'm not trying to bash THD, nor do I have anything at all against that company. For the most part, they make incredible products, have great customer support, and make it easy for tone tweakers to have lots of fun recording, gigging, whatever. These are just not for me, and I encourage anybody considering these, to try and test them first (which is hard to do as most stores won't let you take a new amp and stick an aftermarket converter in it).

Once more, this is not a slam against THD and I'm sure the right application would sound great with these. I will just advise, if you like the sound of your amp as it is, I wouldn't recommend these at all. And if you want a Class A amp, there are many affordable versions of Class A on the market today.

Good luck,

yellowjackets in mesa boogie rectoverb: good cleans, made gain channel harsh and un-usable, still very loud--don't expect low

volume breakup, just loss of headroom. would like to try these in a fender (or similar) combo. WILL NOT FIT IN MOST

HEADS...REQUIRES A HAIR OVER 5 INCHES OF CLEARANCE for the regular model (short model is only about half an inch shorter)

********** If you want some serious volume reduction and low volume power tube distortion, I highly suggest some TADs by

www.smicz-amplification.com ... these are 1-2 watt tube adapters (6AK6, sounds similar to a 6V6) and at only 4 inches tall,

will fit in heads too. ************

fine

Bought as a replacement/experiment for two EL34's. Very simple, pull out old valves insert these little puppies and off you rock !

I use a Musicman Luke, A Fender strat USA series with Bareknuckle trilogy Suite pickups and a PRS McCarty Soapbar. These go through a Fulltone fulldrive 2 into a VHT Pittbull 50CL Head and Marshall 4x12 with V30's. The amp was too loud to hit THAT sweet spot with the EL34's in the venues we play so I thought I would give these a try.I play rock/blues but with more of a rock sound than blues, more Gary Moore than SRV if you know what I mean.
In short amazing, beautifull compression no real loss in headroom but the sweet spot is at the volume I need now.
They have made the amp sound a lot sweeter than it did and the sound for solos is much fuller, the PRS sustains forever.
I now have the perfect sound for me, I was looking to sell the VHT and tried just about everything on the market over a three month period, nothing was as good as the VHT but now that is even better.
Try them they are amazing !

Giged with no problems, they run class A so I would think the EL84 valves will need to be replaced more frequently that the old EL34's but for this sound I would chnge them every month if need be !

Not had to use it yet, but spoke to the owner of the company at the music live show, very nice.

I have played this kind of music in three piece bands for 12 years now and havew been playing guitar for 20. I have owned just about everything oner the years and now I am 31 I have got old enough to realise a 100 watt head is not what you need for playing pubs and clubs( it doesn't make your dick any longer !). The VHT 50 head was the warmest sounding amp I ever tried, still abit to loud to get THE sound in a pub. The yellowjackets have sorted that and made the amp sweeter as an added bonus. So many amps these days are voiced with too much treble. I recently tried a boogie mk4 and had to have all my filling replaced, horrid for live work anyway.
Whatever head/cab combination you use try these and unleash the true potential in your amp at realistic stage volumes.

Class A, works for ALL of the big valve types. EL84, blah blah blah.

I gots an alder mexican strat w/ texas specials in all spots. Strings are 10-46 D'darios. (Tiny ass frets. 10-53s farted out.)Into a hot rod d'luxe
I like stuff like Bad Brains, Radiohead, hendrix, dead kennedys, and this gets those (all those) sounds great-or good enough. you just dime the mids and bass, kill the presence, and put the treble at 4. This gives you great clean that reminds me much of hendrix's axis playing. C-c-c-o-l-o-r.
Crank the amp and it becomes Cream/ Duane Allman-like. So sweet...Not like honey, with that bitter, albeit satisfying hint of bitterness. It is more of the flavor of table sugar-very refined and pure, which i love.
Then you put on a boss os-2 on the distortion side-yes, mids full on- and have the grittiest, most obnoxious grind youve never heard. Bad brains or queens of stone age crunch(friggin EVIL). This thing feeds back so easily, and so purely. I had to bust out the Van Halen, and im utterly sick of them.
dont use the other channels, though. Fender, being the penny-pinching corporate bastards that they are, made these channels bull$hit. don't bother.
I'll expound more on the total assholery of FMIC (fudge mashing industry crooks). This amp stock is FAR inferior to my marshall practice amp (MG-30RCD) and that thing lists a headphone jack as a primary feature. It was the bass equavalent of crack coke. Total BS. I had it for a year stock and hated it every time, which was at least fifty times. I never even gigged with that POS, Although if you feel differently, I can respect that. That either gets you off, which is the entire point of music, or you know ho to manipulate it differently. The clean had a mesmerising quality to at the time, so I bought it.

I got this for Christmas, so idunno

dunno. good product though

I've been playing for 4 years give or take. I'm 15 own a bunch of other effects boxes that I never use.
I know what you think, glowing review from a full-of-crap adolescent. Well, youre absolutely right, but to my credit i dont have dread locques.
And all the people reading this review are crackbaby POD fans who want their amp to sound like a mesa, yet they invariably sound like crap NO MATTER HOW GOOD THEIR EQUIPMENT IS. Play, dont but stuff-its more fun that way, if you really love music
Play these things first somewhere. They may sound like nails-on-chalkboard to you. Or a premature baby(ha ha ha ha)
10 bacause thetubestore.com has dirt cheap shipping, since their psychotic canadians. Im not gonna put anything to identify myself with this posting, because Bush's homeland security gestapo may hold it against me.

What features? It's a tube adapter... you plug it in and go.

OK, these adapters work, but they won't make a Fender amp sound like a good EL84 amp. There is no chime, just a grungey, mushy overdrive/distortion. If you are expecting these to turn your amp into a Vox AC-15 clone, it's not gonna happen. They work OK but are not very versatile and not quite what I expected. I used them in a vintage Fender bassman for a recording session and it sounded pretty good on the project but it was just kind of a one-sound thing. After trying them, personally I'd prefer to use a pedal than the Yellowjackets, I think you'd have a tighter sound and more control. I sold mine after using them a few of times in various situations. I also tried them in a BF Princeton reverb, where to my ears they sounded worse than in the bassman.

I'm sure they are reliable however the tubes seem to run really hot in them, just like in a class A amp so I would always carry extra tubes if I was using them regularly.

I never dealt with it but I'm sure support is fine. There isn't much that can break on these except for the tubes which can be replaced.

I've been playing as a pro since the early 70s. To get an EL-84 sound thru a Fender amp I prefer the sound of the Crowther Hotcake pedal over the Yellow Jackets. They are a good idea on paper but the sound was pretty disappointing to me.

They do what they're supposed to: cut your amp's wattage and convert it into a class A amp using EL84 tubes. I bought the "Shorty" version, which is 4 3/16" long.

They would give any class A/B amp a tone that breaks up more easily at lower volumes and contains rich harmonic overtones.

In a Fender Blues Deluxe, the amp became tame enough to crank full blast without ear plugs. The clean tone became much richer with harmonic chime. When cranked, it took on a smooth crunch that remains clear even with six note chords. The crunch channel became much smoother with more harmonics and great feedback. It did best with the master on full and the drive no more than half way.

On a 65' Deluxe Reverb reissue, the amp's high end improved dramatically, with great harmonic highs that aren't at all harsh, even with treble at 10. Low end was tightend a good deal when compared to the stock 6v6 tubes. With the normal channel dimed, the amp sounded amazing. Not unlike a cranked jtm 45, but at a relatively comfortable listening level.

I own a few THD products and this company has a reputation for rock solid equipment.

I e-mailed them several times and have always received a timely, friendly, and knowledgable response.

These things basically give you a brand new amp for about a hundred bucks. Any tone purist will appreciate the rich sound of a tube operating in class A. There is no comparison as far as richness and character. If your bored with your current amp, these could be a cheap ticket into uncharted tonal territory. I highly recomend them.

These are adaptors with EL84 tubes that plug into your amp's power tube sockets to give you class A cathode bias El84 (like Vox) operation with lower power (power tube distortion at a lower volume). Sweet clean, sweet/raunchy distortion

I play a Les Paul with a Seymour Duncan JB into a Fender Bandmaster head with a Scholtz Power Soak. Stooges/Stones/NY Dolls type riffs. My basic tone is essentially the overdriven amp. This product gives you the classic, REAL tube amp tone. Totally different than preamp overdrive. It acts like an acoustic, but hitting it harder gives your more compression, distortion, and harmonics.

This is a well-made product. THD knows what they're doing. The operating voltages and currents of an EL84 are lower than those of a 6L6 or El34, so the amp's transformers get more tone from less work. A lot of amp mods try to accomplish what these adapters do, but with the original tubes. These work with smaller tubes that will generate less heat in the amp's transformers. You can fry the EL84's (cheap little guys, look it up), get a great sound, and your amp won't suffer a bit.

They are great. This is important! Call or email before buying. They have many versions not available through dealers. They will make sure you get the model that works.

I've been playing about 15 years. You've read about crank-it-up tone. this is it. The Beatles, Stones, Zeppelin, even BB King used amps that these can duplicate. Warm, sweet, crunchy. Amazing detail. The difference between a great clean and great dirty tone is in the guitar volume. And it's at a much lower volume than a Marshall stack. My amp cost me about $200. By adding these it's comparable to $1000+ amps. Not a metal tone at all, but some incredible classic rock/blues/jazz tones are right there and ready to use. Don't blow your money on the latest cold/fuzzy Marshall. Stick these in a silverface Fender and get a good pedal for leads. This is the sound of old tube amps. 'Nuff said.

These are power tube converters using low power EL84 output tubes(included). You just pull out your EL34's, 6L6's, 6V6's or 6550's and put these in their place. BTW, "YJSD" is the model number for this and covers all the tube types I mentioned, not a different model for EL34's vs. 6L6's. They all work with these converters. I'm not going to rate this category because it's just a pair of power tube converters. This section was meant for amps. I guess a feature would be that you can try these in many amps and not have to re-bias. Or you can try different brands of EL84's.

I use a Gibson Flying V with EMG 81's and an Ibanez RG550. My amps Marshall 3203 Artist & Marshall JMP Mk2 50watt(heads). Marshall 1960 cabs. I love these things! It made the already great sounding 3203 better with more distortion. It does thin out the sound at lower volumes but the point of these things is so you can turn it up. Then it starts to thicken up again. I like power tube distortion and warmth. I have a Power Brake but didn't like bringing it to shows and the loss of high end. The Yellowjackets has the high end in spades! Not in a bad way. I bought these, went to my rehearsal space, plugged them in and when I heard the sound I was laughing because it sounded so good. I played all night.

Like someone else wrote, they did smell kinda funny at first. You know that 'electronics on fire' kind of smell. I played the day after I got them outdoors in 90 degree heat without a problem but I still brought a backup. I've only had these a couple days so I can't rate this. But if it blows up my amp I'll be back.

E-mails are returned quick. Really helpful.

I've been playing 22 years. I'd get more of these if I had to. They're a cool option to have, you can always put your old tubes back in with no changes and it's simple. I haven't owned that many amps but this is the best sound I've had so far.