Good NOS 6K11 for Ampeg V-4B?

[Majin GeoDooD]

Hey all, when I got my V-4B the 6K11 in it was a GE.

I went through some troubles with the amp and finally got them fixed, after which I decided to retube the whole thing.

I bought a NOS 6K11 from thetubestore.com and what arrived was a Zenith.

Upon putting it in I was getting early breakup when adding any mids, a quick google told me that the 6K11 does something with the mid-shaping circuit.

Is my GE 6K11 good enough, or is there a better NOS 6K11 that I can get? I see more than a couple different brands on eBay..

[slider313]

Zenith tubes were made by the big three, RCA,GE,Sylvania,depending on the tube in question.The most common I've seen are Sylvania's as even the design and color of the box is the same.If the GE is working and there's no noticable drop in volume or microphonics,then leave it in.It is my experience that GE and RCA compactrons sound better than the Sylvania brand. As a matter of fact,it holds true to their 12ax7's also.JMHO.

[Majin GeoDooD]

Guess I'll just leave it as is, then. I would still like to know why the Zenith tube screws up the sound so much.. :/

[Blue Strat]

. I would still like to know why the Zenith tube screws up the sound so much.. :/

Probably because there's something wrong with it. One brand of tube won't act radically different (negatively) than another brand unless there's a problem.

[Majin GeoDooD]

Probably because there's something wrong with it. One brand of tube won't act radically different (negatively) than another brand unless there's a problem.

Yea I know that.. it's just a bit upsetting that I bought an NOS tube and it doesn't work right at all. It's one thing if it introduces a little breakup.. but it was a lot.

[gasimakos1]

i'd be more than willing to take that zenith off your hands if you still have it. ill shoot you a little cash for it. i'd totally be into the early breakup. i'm using my v-4b for guitar and i've been replacing preamp tubes, trying to get the most gain and breakup that i can. if this thing breaks up as much as you say it does, that would be bad ass.

let me know
-george

[mark norwine]

There is **ZERO** science to substantiate this, but I'm going to say it anyway:

After years & years of professional amp repair, I can tell you from experience that Ampegs....unlike almost all other brands of amps.....seem to be very, very picky about the tubes installed in them. Hit or miss, no rhyme or reason....no pattern at all. The biggest problems I've had were with 7199's, 6BK11's & 6U10's. I'm talking about tubes which would be wonderful in one amp & unacceptable in another.

I can't explain it.

Your tube could be 100% fine.......but that (particular) amp just hates it.

Don't believe me? I'm with ya!! If I hadn't experienced this for myself.....over & over & over....I wouldn't believe it either.

(Yet I adore old Ampegs....)