Switching from EL34 to EL84?

I have been told that my Musicman HD130 would sound much better if i were to have it biased to run EL84's but this guy also said that i would have to change out some of the caps. The wiring is original from what I can tell What I wanna know is would my amp really sound better if I were to switch to EL84's? I'm not gonna guinea pig my amp on some ones opinion.

EL 84's are nine pin miniature tube and EL34's are octal large tubes. If you want to change them, you would have to change sockets, etc, and the MM plate voltage would fry a 84. I thing somebody is smoking you. You could change to 6l6's with a re-bias. Are you sure that is not what he meant?

He might be talking about THD Yellowjackets.www.thdelectronics.com/products/yellow_j acket.htm
You take out the O/P tubes (6L6, EL34, 6V6, 7591)
plug in the appropriate Yellowjacket(s), then
plug EL-84's into the Yellowjacket. No biasing
needed. Class A operation.
A friend uses 'em in a Fender Deville, replacing 6L6's. Basically they lower the amp's power and headroom. They make his Deville sound like a
hot thick controllable Blues Jr. But it still weighs a ton.
I wouldn't use them with MusicMan, which carry non-typical plate voltages. email THD about it, maybe I'm wrong.

no this guy was talking about changing capicitors out and what not i am gonna do it im just wondering why would you alter a perfectly good original MM amp im satified with the sound i was just wondering is it really worth altering you ramp over?

Hi players
I started using yellow jackets in a beater 2-10 65. It is good. At first some JJ's, EL84's. Nice singe, sear. Then some 7189's (telefunken~heavy duty 84's) found on ebay. These sound mushy at low power, but at high power, which I have heard is a bad idea, these just flat out jam. The JJ's produce a static sound when at high power, the teles do not. You just dime it and chime it. I am going to load up a 4-10 130 with a quad of these asap. It's easier on the ears when playing Fenders. I always like Gibson humbuckers through stock Musicman's but have not played one in a long time. The single coils are given a bouyant crunch with some, not a lot, of headroom. You can do this if you control your attack however. Please refresh my mind on the warning about using hi setting with the yellow jackets! THX

as I understand it,musicman amps on high power run a plate voltage of 700vDC,this should fry any el84 in no time ,even the 360vDC at half power seems abit hard on that tube,the yellow jackets give these amps a kinda kool class A sound ,but it makes for a really heavy 15 watt amp,nice for studio work ,but kinda a pain for stage.

I don't know what causes the voltage draw-is it 700 V at all times? Or just when demanded by high settings/hi volume? So far, high power has been run about an hour. No damage that I am aware of, and the tubes run cool. Any thing which affects plate voltage I would be interested to lean about. 84's becoming my fav. Could something be out of adjustment in the amp which causes a lesser voltage?

I checked the THD site-apparently the voltage is automatically regulated to protect the tubes. No rebias needed for class A operation either. Plus, you can use half yellow jackets/ half EL 34 or what have you.