ilovefuzz.com

I've always gone with the stock 7027s when replacing the tubes in my V4 and V2, due to my first tech way back insisting on it. Over years I've seen a bunch with 6L6 and had a bud buy one that had been modded for EL34, and have read that ampeg offered a "performance upgrade" option for V4s that came with 6550's.
So what do peeps use and like, and how's it change the tone?

I still shell out for 7027s in mine, I’ve tried 7581s and KT 90s but don’t like the sound as much.
The 6l6s have less head room; also EL34s have a bit too much top end fizz when over driven for my taste.
The plate voltages of late ’60-early ‘70s are very high and 6L6s are a tad over worked.
They work but…
KT66/7581s are a better choice for the 6L6 sound

MM

I intend to keep the 7027s in mine because i'm afraid of modding it.

My VT-40 was already modded for 6550s when I got it. It sounds great, but I'm not sure which route I'll take when it needs to be retubed. I'd just stick with the stock 7027s if that's what you've got now though.

Interesting, I'd be curious about how different the tone is. I've often thought about modding my V4B for 6550s, but would probably not touch my V2.

I've never actually played any Ampeg amps other than my own, so I really don't know what the difference in tone is from the 7027s and the 6550s either.