THD Yellowjackets 6L6

I'm can't remember the Yellowjacket model I'm using but its for 6L6s. This model cuts to output power by about 60%. You can also get the same thing without the power cutting ability.
These are totally amazing! Just plug 'em in and fire up. They'll have your old, loud, clean tube amp screaming with class A EL84 grease! If big, clean headroom is your thing, then these are probably not for you. If you're looking for a little hair around the edges of your clean notes or very kick-ass greasy overdrive, then order some.

I purchased these to tame a Blues Deville, and they did the trick. I've since sold the Fender and now run these in a Pignose 60 watt tube head fed through a 4x10 cab. My Telecasters just sing with these. Turn your guitar volume down and they clean up perfectly, roll it back and grind to your heart's content!
These will not make your 6L6 sound like a Vox AC30, but class A even harmonics are definatly there. If your a stickler for classic 6L6 tone, you may not like these, but for about $100.00, you can have two very cool amp sounds.

THD is known for their American made, quality products so I'm not worried. And for what they cost, I wouldn't mind having to replace them in a few years. Note: I ordered my first set from thetubestore.com and one on the plastic center posts on the adapters was broken off. Everything worked fine, but I emailed thetubestore and told them about it. They sent me a new set, didn't charge me shipping on the replacements, and had my credit card refunded as soon as they recieved the damaged set. A great bunch up there in Canada!

Never delt with them directly, but they're small and I'm sure you could talk to the techs any time you had a question.

Played (bashed) for 21 years now and live for a dirty rock and roll guitar sound. These turn any decent sounding 6L6 amp into a class A monster! This is now a must have in my signal chain. They have a very unique tone quality all their own that I've come to rely upon. I would/will replace these if and when needed. If you have limited space in your amp, you can order a shory version. The adapters and the included Testla EL84s a quite long. This is an incredable upgrade for $100.00. You wont be sorry. Check out ebay and see how many people are trying to get rid of them...always a good indicator.

Just a quick update. I gigged with YJs in my Hot Rod Deluxe for the first time Saturday. In every respect, this amp is superior with EL84s. There was no lack of stage volume, and the tone sits in the mix better than before. The clean channel is bright and chimey, even on the edge of breakup. The drive sounds "full throttle" even at the same volume settings - and the way it mixes with bass and keys is sweet! The "more drive" boost yielded sustain and harmonics that transcend the Fender sound. I'm hooked. This is a great product!

Duet Tube Converters -- Converts 6L6 Class AB Power section to EL84 Class A power section.

One feature -- and it is mind bogglingly cool

I got these as a last resort for my Hot Rod Deluxe. The amp was never "it." It never had the high-quality chimy, clear, inspiring tone that I wanted from it. I first changed to a Celestion Vintage 30 speaker -- and it got louder and tighter -- but not more "inspiring." Then I put in NOS tubes. No meaningful improvement in the "magic."

Then I bought the Yellow Jackets. Simple swap job -- turned on -- clicked off standby -- holy crap. The chime was there. The magic. The inspiration. Still very loud. But useful loud, sweet loud. I never wanna stop playing loud.

Here's what was wrong before the speaker change and the Yellow Jackets: all the HRD had going for it was huge bass, and ear-splitting power. I've owned a dozen amps in my twenty years of playing, and this was the loudest of them all. Louder than the 100-watt Yamaha I had in High School, or the 135-watt Peavey I had in Junior High. But the Fender Hot Rod Deluxe had no inspiring sounds. Below "6" it sounded mediocre at any safe volume level. On the drive channels, the distortion sounded amateurish and flabby (like shit). And, worst of all for a Fender, the reverb is incredibly boingy and useless above "3". No lush, rich, reverb here.

But now -- the HRD with Celestion Vintage 30 and Yellow Jackets sounds near to perfect. With my Robert Cray Strat -- this thing has chime, mojo, vibe, clarity, richness and lots of harmonic content above the fundamental. It has what it never had before. I don't think I'll ever need a better amp.

?

Owner handles it personally.

One feature - changes your 6L6 amp to EL84 Class A operation. Mine is a Fender Hot Rod Deluxe w/clean and drive channels. With respect to the single purpose of the product, it gets a 10. I purchased the YJs and the EL84 tubes separately at a cost savings.

Sound. This is complex, I'll try to keep it brief. The HRDx (with stock speaker) has a lot of bass for a 1x12 combo. I play a EB Music Man Silhouette with a HSH pickup set. I play in a cover/party band with pop-rock songs spanning the 70's to today. I use a Tech 21 XXL distortion pedal in front of the clean channel for crunchy rock, or the HRDx's lightly overdriven sound (drive on 3 or 4). Problem: my single coil/coil tapped tone was wallowing in bass. I had to use amp's "bright" switch and crank the presence to get some sweetness and clarity - an inconvenient amount of tweaking for gigs.

The YJs completely change the personality of the amp - mostly for the better. Brighter tone on the clean channel. Tighter bass. The clean channel distorts at a lower volume, and the result is a very cool "vintage british" OD sound - rich and articulated even with full chords. The drive channel OD is hotter than before. Essentially, it's now an amp with two OD channels, which leads to a couple of shortcomings:

The YJs impair the ability of this amp to be used for clean sounds at gig volume by cutting the power output by half. The background noise level is increased - quite noticeable at higher drive levels. I was able to remedy the noise problem by substituting a lower gain 12AT7 in the preamp section (V2). Now I'm really happy with the sound, but I regret the loss of the clean channel at gig volume.

Seems to be a reliable product (no moving parts). The EL84 tubes extend further into the cabinet of the amp, and I worry that they'll melt the power cord if left in contact - other than that, no worries.

No experience - can't answer.

Been playing for 15 years as a hobby musician, part of that time as a bassist. I have an EB Music Man Silhouette, a Sterling bass, a Taylor acoustic-electric and a variety of pedals. I'm a huge U2 fan, and the YJs get me closer to the sound of the Edge (with help from a Deluxe Memory Man). I've added tilt back legs and a Jensen C12N to my HRDx, and I'm now very attached to it. Were it lost or stolen, I'd probably buy another - but not without looking at a RI Deluxe Reverb or a Mesa Boogie Nomad first :-) Sound is very subjective - the YJ tone may not be for everyone. But for me, it's a good thing - and if I want the original tone of my amp back, I just pop em out and put the 6L6's back in. Cool!

Tone update only

I previously submitted a review for the YellowJackets in my HRDx. I finally got around to trying them in my Sovtek Mig 60, and do not like the combination. Although, in the HRDx I had to crank the treble down and got sweet tones, I was unable to find any usable settings on my Mig 60 to make the YJ's sound good. I have more difficulty getting a sweet tube tone out of the Mig 60 than the HRDx regardless of the output tubes, but I am going to experiment some more, probably with different preamp tubes. I tested the YellowJackets in the Mig 60 using (v1-v3) Chinese 12ax7 + JJ ECC83 + Svetlana 12ax7.

They have only one feature which is to transform a 6L6 amp into Class A EL84 operation

When I first read about these things, I thought it was all hype to the highest degree. If Class A operation requires such sophisticated engineering and most Vox amps are reputed to be so unreliable(well...thats what I heard) then how could a Fender amp be so easily converted? Hell if I know... but these things do exactly as advertised and then some! I stuck the Yellow Jackets in a Blackface Bassman top and I could feel the difference under my fingers immediatly...instant squish and a very soft ,detailed high end..I AB this unit with my Top Hat Club Royale and while they do not sound exactly alike, they are very close! For $100 you get a whole new amp with no modification at all to your Fender or whatever you are using. If you like class A as I do but are not ready to put out big bucks to buy a Matchless, Top Hat, Dr. Z etc. Try these and you won't be disappointed. What a great product!!

too soon to tell.

I emailed THD several times prior to my purchase and they responded very quickly and were very helpfull.I suggest you do the same as they can tell you what model is right for your amp and some of the distributors are not always aware of new developments in the product lines.

I really can't rave enough about these. It would be one thing to achieve the conversion to Class A and have an OK sound, but these things really do sound great! And if you tire of that particular sound, simply pop the original power tubes back in. It's like magic. I will definely get these things for my EL34,6V6 amps and my Ampeg Reverberocket II.

Converts 6L6, 6V6, EL43 Class AB > EL84 Class A
Plug and Play!

See my reviews on Tubeworks Real Tube and Fender Hot Rod Deluxe for more info on my setup. I play a Strat w/ bucker in bridge into a Fender Hot Rod Deluxe or a Sovtek Mig 60. I have not had a chance to try them in the Sovtek yet, because that would require removing the chassis from the head. In the Fender HRD, these things are amazing. I already have lower gain preamp tubes installed, and adding this feature just makes the tone JUICY. I can achieve power tube distortion at a much lower volume, and the Class A sound is great. For $70 I got a whole new amp! Just wish they were a BIT louder.

Haven't had a problem yet. Construction looks solid.

Haven't needed it.

I highly recommend THD Yellowjackets to people who are trying to tame their tube amp and/or people seeking Class A tone. I think I will get most use out of these adapters while recording.

www.deharmonic.net

Well...it only really has one feature but it's a killer and, as far as I know, nothing else does what the Yellowjackets do. Thus, the "10".

I use them in a reissue Marshall Bluesbreaker combo. When I plug them in the output drops to about 15 watts and it sounds AMAZINGLY like a reissue Vox AC30 (with Greenback Celestions like the Marshall) that I once had. For a hundred bucks or so this can't be beat as both a way of getting more sounds out of an amp as well as cutting the volume at which all out power tube distortion is reached.

The Yellowjackets themselves have never caused any trouble and the EL-84's used with them seem to have about the same life as the KT-66's I use in the amp when the Yellowjackets aren't in there.

I own these and a Hotplate power atenuator. I've never had to find out what THD's customer support is like because neither has ever given me any trouble at all.

The only competition for this product is really a second amp like an AC15 or other small tube amp. The Yellowjackets are a lot cheaper and the only disadvantage is that you can't play the amp both ways at the same time or switch immediately from one to the other during a song as you could if you had two amps! The only inconvenient thing about them is a result of my amps layout which makes the tubes awkward to access when I wish to switch back and forth.

I'm using these in a Mesa Boogie Nomad 55 combo amp with one Weber Thames 12" speaker. No features other than changing your amp into a class A vox-like amp which is pretty damn cool in itself.

Ok, I was shocked at the sound. I love the Mesa Nomad but there was something that just wasnt' clicking with me when I compared it to my Mesa rack system with a Triaxxis preamp and Dyna watt power amp. The rack system is so smooth and bluesy with a nice upper end chime. The Nomad was thick and raunchy. Then it hit me, the Mesa Dynawatt amp uses el84's. I didn't think that running tubes under there threshold (i.e. clean) would color the sound. I was wrong. Whether or not a tube is pushed has no bearing on the tone. Tone is tone, clean or distorted - EL84's have a unique tone that I love. So I figured I'd buy the Yellow Jackets to drop down the power and see if that magic would come to the Nomad. Well, volume-wise, don't expect a volume drop. The output dropped to about 30watts but these are class A watts which are loud. What I have noticed is that beyond a certain point, the amp won't go any louder but just compresses and distorts the output stage, whereas with 6L6's or EL34's, I can push it farther and louder before output stage distortion hits. The tone is there my brothers!! That rich, harmonic, chimey, Brian May tone. Very tight and focused in the upper mids and treble. It may be a little too bright for some amps but I have a Weber speaker that is chimey but not icepick harsh. El84's just have the sweetest tone ever and running them in class A is even better. Its like getting a whole new amp.

I've owned other THD products and they are built to last.

#1 product support. Phone personel is great and Ed DeGenero always answers his emails.

This is a must for any serious musician. Considering this is a plug-n-play system with no re-biasing for under $100 bucks is a no brainer. It will transform your amp into a semi-Vox. Honestly, my Boogie sounds closer to a Vox than any modeling amp I've ever owned, and I've owned several. That upper end chime is just amazing. I wouldn't really say its good for heavy metal since the low end is just not that big. Its tighter and more focused. Its just a rich, chimey sound that can only be appreciated by fans of EL84's (Matchless, Vox, etc.)If I get tired of it - I just pull them out and put in my 6l6 or el34's without any tools!!

They haven't got any features. You pull the old tubes out and put these in. They are self-biasing, which is a plus. That deserves a few points. As does the simplicity, I suppose. And the nice colour.
Alright...I'll give it a 10 then. It is pretty well like having an extra amp after all.

I got these for my Fender Hot Rod Deluxe (by the recommendations on this review page) because the HRD is too loud for many of the venues I've been in recently. I've tried turning it down but tube amps don't sound their best when the volume is too low. I tried a Laney LC15 but it was too bright sounding for my taste with the 10" speaker and when I found that the Yellowjackets would give my HRD a similar output I sold the Laney and got a set.
When I first tried them I was disappointed because the sound was very bright and piercing...like the Laney (I play a Telecaster which has enough treble to begin with). I then thought that it was some aspect of Class A operation that was causing it but after putting a question on the HC amp forum and also finding an old article in a guitar mag I learned that it's the EL84 tubes (which the Laney also had). 6L6 tubes (and EL34s) tend to emphasise the bass frequencies and EL84s tend to emphasise the upper mids and highs. Any amp which has been designed to bring out usable highs with 6L6s (like the HRD) will cut glass if you just plop in EL84s UNLESS you do some major EQ adjustments. I therefore played around and found that rolling off ALL the treble (and having the bright switch off) and having the mids, bass and the presence at about 4 or 5 made a fantastic sound. I also tried it with the treble at 3 or 4 with a Boss EQ pedal in the effects loop trimming off the highs a little and it sounded good too.
I've not gigged with it yet but it seems to have a much tighter bottom (oo er!) and switching between pickups isn't as much of a shock as it was with the 6L6s. The clean channel is chiming and almost like it has a chorus and the overdrive on channel 2 seems much smoother too, and it was good to begin with (since I'd put Tesla preamp tubes and a Celestion Vintage 30 speaker in). The 'More Drive' button results in a creamy overdrive boost rather than the shriek it used to make. It seems to have much the same power as before since a 20w Class A will hold its own against a 40w Class A/B, but the tone at low volume seems more usable. I'll see how it is when I gig a few times but volume issues aside, I think I prefer the new tone and feel. AND I won't have to pay anyone to rebias the amp when I replace power tubes anymore since the yellowjackets are self-biasing.

Too soon to say. I don't expect any problems since the reviews don't seem to show any problems occurring.

?

I've played since 1969 and I'm fussy about my gear. I've explained most everything in the 'sounds' section so I'll just say that I think these are dead cool and I like the sound (it'll take several gigs to get the feel of them properly but I'm pretty confident they'll be OK).
I think I'd replace them if I lost or broke them.
It's important to realise that you need to alter your EQ settings when you put these in.
I'll give them a 10 since you're virtually getting a second good amp for #85.