THD Yellowjackets

Hi guys,
I was wondering if anyone has ever used yellowjackets in thier Musicman Amp? I'm not realy considering it, on account of something to do with odd hotplate currents. However, I did put a pair in my JCM-800 combo, all thier combos had diodes, but the yellowjackets realy do make it sound oh so sweet, warm, and voxy sounding. So I just thought I get your alls opinions, and how they might sound in your music man if you tried it once?
In case you're not familiar with yellowjackets you can buy them or just get a general description on the musiciansfriend.com websight. Thanks.

I have actually tried them in my Music Man 410-65.
First, ALWAYS run the Music Man amp in the low power setting! When the amp is in the high-power setting there is 700VDC on the plate pins and this will destroy the Yellowjackets! There is closer to the "normal" 400-450 Vdc when the in the low power mode.
The amp character does dramatically change, but I cannot say if it changes in the same direction as other amps because the plate current is typically about 1/2 what "normal" guitar amps run because they develop their power at almost twice the plate voltage.
Groove Tubes also sells a "Yellowjacket-style" power reducing set of adapters and EL84 tubes. The same warning applies... lock that amp in LOW POWER mode to prevent damaging your amp!
Steve

Thanks for the tip Steve.
I might try them after all if you think it's alright.
Eventhow the plate current of a Musicman amp isn't typical, the yellowjackets still convert it to a class A amp right? Were the pick dynamics any more prominent.
Half of me says not to mess with perfection, but the other half can't help but be curios. Thanks.
By the way, sorry for all the typos in that initial post guys, I get carried away sometimes.

Since the amp only develops a fraction of its original power (probably about 12-15 watts in a Music Man 65 watt model in the Low Power setting) it didn't make sense for me to leave them in for normal use (dragging around a 15 watt 65 pound 4 x 10!).
I was also concerned about the longevity of the YJs in the Music Man because the plate voltage as at the high side of their range. The tubes themselves may be run in a Class A mode but as a pair they have to be run in a Class AB mode in order to drive the output transformer! True pure Class A can be done with a single tube and doesn't require a pair.
The amp does take on a Vox-like chime (as does any amp using these), especially when you are not used to hearing the EL84s! They overload more easliy and the distortion is very smooth!
I would use these for recording without reservation but I would want to experiment with them a bit longer before I made a habit of playing out with them.
Steve

I had a pair of Yellow jackets that I tried in a RD-50, but it sounded too flutey in triode wiring, I like the sound of Class-A pentode personally, since it sounds more like the way the MM amp is set up, but with the quality we are most after like the compression and lower output tube distortion, it retains the bite of the stock amp, but with all the sweetness of EL-84's. I have in the past wired up the triode/pentode switch for Fender guys, and most of them prefer the pentode over triode, again personal preference. Also the negative bias/cathode bias switch works nice in some amps, simulating a calss-A power amp like a Vox AC-30, which is cathode biased, and not truly class-A as advertised. Class-A is single ended and sometimes more than one power tube is wired in parallel. When there are two plate side-windings off the output tranny, that is truly push/pull but can be wired cathode bias and triode or pentode, and sounds like Class-A. A true class-A example is a Fender Champ, 1 powertube (6V6). I have modded my old silverface vibro-champ to accept a 18 watt output tranny and replaced the rectifier tube with a FRED rectifier, and wired that rectifier socket to accept another power tube in parallel, which almost doubles headroom! A very sweet setup that is louder than you would expect from a champ. It has a Weber 50 watt 8" replacement. Great blues jammin amp!

For those who are interested, I think you can order THD Yellow Jackets now in either Triode or Pentode wiring. There is another company making them too, but I am not sure who right now.
Ed

I have a 210-65 sent with yellow jackets. A nice sound, but much lower volume. Reminds me of a 12 watt musicmaster bass amp I once owned, only sweeter. Not sure I will keep them. Considering parting out the amp due to other vacancies in various amps. One needs a tank, one cabinet needs a chassis. Some are missing knobs etc. Someone stop me please!

What I don't get about these yellow jacket things is that they seem to take all the midrange punch right out of the sound. It's like a Fender...not sure I like them, may offer them on ebay. They're newish, with very fresh looking J and J 84's. I'm used to using a 2-10 65 like a large set of headphones. Just set everything at 10 and slump real close to speakers, placing your head right in between.... The yellowjackets make it like a 10 watt Fender. Will putting power on 'high' damage anything other than the jackets? Thanks

I am using the jackets with Telefunken 7189's. Now I only want that sound, because of the seeming 3 dimensional quality of the sound. I spoke with Ed at THD and he says unequivocally to NOT use his product in MM ammps because, in his words, they are class B amps, and when you 'beat the snot' out of them, the voltage is quite hard to regulate. I have run on high, dimed, and it is just the best thing I have heard. Maybe I am inexperienced with amps and their different sounds, but I can't see going back with the big bottle 6CA7's after this. The only thing that scared me was an intermittent crackle which has proved to be a loose tube fit in one of the jackets. My test amp is a 2-10 65 with the PI, also a Telefunken. These tubes sound better than any vintage tube I have sampled. They seem to 'breathe'. I have secured a quad and will try a 4-10 130 soon.