THD Yellowjackets

[toejam]

I got the Yellow Jacket Uni version for my THD Univalve head, because I love the EL84 sound! I can basically use any tube I want in the amp, and usually I use the new JJ KT77 now, but the EL84 gets used fairly often as well.

[Soloist1]

Ran into a road block. The GT 928PR's are rated for 450v max plate voltage. I bet the yellow jackets are the same. I'll have to call THD tomorrow and find out. The nice folks at Groove Tube were pretty helpful and told me a new one for Marshalls, Soldanos and other high plate voltage amps are in the works and might be available after this coming winter NAMM. That probably explains the reviews on Harmony that said they cooked the resistors and got hot as hell. Read that for both the YJ and the GT. So Pete you might not want to try those YJ's in your SLO clone.

[Twisteramps]

DOH! I'm glad I didn't try them in the Randall RM100 - it was pushing 530 or so volts on the plates. KA-BOOM! lol

Pete

[charvelguy]

The pins were tight going into the tube sockets much moreso on the 928's than the YJ's. I run mine in both 50w Marshall master vol JMP's and have not encountered any problems. Typical plate voltage is about 450 for a 50 watt Marshall depending on how it was biased.

I scruntized both makes pretty carefully.. and I'm not a big fan of GT products either but these lived up to the review and the marked differences between the two brands. Myles Rose works for GT as does "Jimmy".. the guy who designed these... they are pretty decent even tho we got off on the wrong foot when trying to get some answers and comparisons to THD YJ's. Obviously.. their opinion of their competitor is likely pretty biased but I think they are striving to put out some guitar products that are in line with their amps.. which are quite well built.

[Twisteramps]

Myles is an... interesting fellow. He used to post on HC all the time, not as much anymore.

BUMP FOR THE NEW FOLKS!



Pete

[charvelguy]

He sells a bunch of the custom work and various GT product on eBay.

[Soloist1]

Myles was the guy I talked to actually. At first he said sure we have run those in SLO's before. Then I think Jimmy chimed in and he said hold on. Then he told me don't use them and told me what Jimmy said about making a new one. I guess the plan for them is to make one that even handles the Marshall Major. Typically I read 490 to 499 for my plate voltage. Depends how hot I run the tube.

[charvelguy]

I hope they consider shortening the base a little but it likely won't happen. One complaint I had was they are a little wider in diameter than a yellow jacket. Some amps tube ring retainers would have to be removed in order to use them. Good thing I did not try these in a hundred watter or a 150 clone.

[Soloist1]

THD has a yellow jacket that is rated at 510v or less. Of course it's the cathode version that has the ground wire. No mention of what the YJS's voltage rating is. It doesn't handle the 6550 or Kt88's so I'm guessing it is probably 450v max.

[Soloist1]

Found the info. You should be good to go Pete. They claim voltages under 520v for the yellow jackets. Let me know how they sound in your SLO clone. If they are still bright and thin I may wait for the GT redesigned ones.

http://thdelectronics.com/pdf/yj.pdf

The only bad thing I see is that most EL84's operate at 250v and have a max of 300v on the plates. The yellow jackets claim to reduce plate voltage up to 100v. So anything over 400v will probably burn tubes up real quick. Lord Valve has a Russian one that lists the max voltage at 500v though. The Russian EL84 made to survive hell I guess.

[Shawn Lutz]

THD does make a YJ with a shorter base....if you do decide to get them specify you want "shorty" versions otherwise you may not have enough room to fit them in.

So just for reference there are 2 different types...YJ's that ONLY convert to EL-84...YJ's that convert -and- power reduce. Both are avail in both short and long versions.

With Tone-approval is so subjective, while I always read up on shit I but I take everything with a grain of salt and make up my own mind. Often times from one end of the spectrum to the other...like Charvelguy and my opinion...I think they were cool and he thinks they suck what matters is if you like them or not Part of the reasoning of posting the clip of it...you ears can describe things that words can't...saves a lot of typing too ...heheh.

[charvelguy]

Did you ever try the GT 928PR?
because I've owned and used both... hence, the basis of my opinion and my preference for one over the other.
I used the YJSD.. I know their claim of "50 to 70% power reduction" is a bunch of malarky. I'm being objective and not just simply biased.. if the YJSD's had done it for me.. I would say as much.
The Groove tube product attenuates far better without the thin and crispies which is my opinion based upon a side by side comparison.

Oh...what guitar did you use in that clip?

I have the same setup as you only it is a 50watt.

..I think I can dig up the backing track from a Brit Cd Guitarist mag that featured that song a number of years ago.

[Shawn Lutz]

Did you ever try the GT 928PR?
because I've owned and used both... hence, the basis of my opinion and my preference for one over the other.
I used the YJSD.. I know their claim of "50 to 70% power reduction" is a bunch of malarky. I'm being objective and not just simply biased.. if the YJSD's had done it for me.. I would say as much.
The Groove tube product attenuates far better without the thin and crispies which is my opinion based upon a side by side comparison.

Oh...what guitar did you use in that clip?

I have the same setup as you only it is a 50watt.

..I think I can dig up the backing track from a Brit Cd Guitarist mag that featured that song a number of years ago.

No, I have never tried the GT product as I had no need, I was happy with the results of the YJ's.

I only used YJ's in one amp, the 2203 so that is what I based my opinion on...I'm not going under a blanket statement that they'll work as effectively in every one of my amps Heck I took them out to test the amp with just 2 6550's in 50 watts.....I left it that way the YJ's have been sitting in the box ever since.

I cant remember the guitar I used for that clip but chances are it was a floyded dual hum strathead

[Twisteramps]

I used the YJSD.. I know their claim of "50 to 70% power reduction" is a bunch of malarky.

To be fair, it is true - an EL84 puts out much less wattage than a 6L6 or EL34 tube. But, it's not a percieved volume cut. There are no tricks for getting more than about 18 watts out of a pair of EL84s in a guitar amp, and even that is pushing it. Mesa is full of crap on their '22 watts' with a pair of EL84s. But even that is over 50% reduction in a 50 watt amp.

Pete

[charvelguy]

Well.. I see your point and I respect your views as well as preferred taste. Again, unless one has tested the two in a comparison situation like I did the point is one of contention based upon what is known, but not necessarily experienced. I do agree..usually a pair of EL84's can put out 20 watts, clipped likely more.
However.. I did perceive a noticable difference in not only tone, but output with the same settings for both types. While it is not a true side by side test..look at the bench test.. you will see the bench equipment/meter doesn't lie. Groove tubes had a truer level of attenuation and there was a perceivable level difference between the two.

I'd be happy to loan you a pair, you can decide for yourself.