software

great? good? ok?

I toyed with the idea about a year ago in my DRRI, then I replaced the speaker...now I don't want to change anything.
I would like to hear some opinions though....

I got a pair of yellow jackets and used them for a while in my marshall jubilee.
There was a small but definitely noticeable change in tone. It made the gain channel a bit sweeter and gave it a really interesting character of its own. It took a bit of headroom away from the clean channel though, so in the end i sold them on ebay.
All in all i would definitely say they are worth a try, but i was left with the feeling that an amps circuits have been designed for use with a particular tube type, so although the yellow jackets may give you a different tone, the chances are you wil prefer the tone you get with the stock tube type.
Having said that, i definitely think they have a use when it comes to getting power amp gain at lower levels. They are not gonna help much at bedroom levels, but at rehearsal/gigging levels you will probably be able to turn the master volume on your amp a couple of notches higher with the yellow jackets, and for some people this could be a big blessing.

I tried them with my Crate Blue Voodoo and they sounded pretty bad. I assume this was just my amp not digging the EL84 tubes.

i used to run them in my marshall. i thought they sounded pretty good. it let me take a firebreathing beast down to a volume that was usable for rehersals and smaller gigs. it did change the tone, lost a little bottom but still sounded good.

Yup....used them in a UniValve amp; in a Hiwatt DR504.....sounded great in both!

I still have mine, but they're just sitting around.
I really wanted that el84 tone so I put them into my fender hot rod deluxe, which uses 6l6's stock (big change in tube type). As far as the change in tube type they're still wasn't that big of a difference in tone, like Zack said, I think the circuit is just designed and voiced for 6l6's so I bought the american made groove tube 6l6's and really liked them in there. The el84's lower power output was hardly even noticable on that amp, and it barely even changed the quot;feelquot; of it, which is what I consider most when looking at amps.

As far as the el84 tone I had to have, I saved up and bought a gibson les paul jr. amp, and it is pure heaven. That is the best sounding most alive amplifier I've ever played. (great power tube crunch!)

i think it depends on how you use your amp. i like to play with the amp cranked up, using the el84s in there gives much less clean headroom and that spongy chewy sustain.
run at lower volumes i didnt notice as much of a difference.