From tremolu–(at)–ol.com Sun Nov 20 09:58:47 CST 1994
Article: 32710 of rec.music.makers.guitar
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From: tremolu–(at)–ol.com (Tremolux)
Newsgroups: rec.music.makers.guitar
Subject: Re: TUBE QUESTIONS
Date: 20 Nov 1994 04:15:19 -0500
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I have one of those 80s Concerts (a 2 x 10), those are the Paul Rivera
abortions. Anyway, the BEST output tube for you to use would be for you
to find a NOS American 6L6GC. There are NO REAL, honest to God, 6L6GC
tubes being made today, period, regardless of the lies you hear from
boutique tube sellers.

The best current production 6L6 type tube is the Sovtek 5881, which
electrically is a 6L6GB. (Notice the suffix here.) A GB is not as
powerful as a GC. The GC’s had a 30 watt plate dissipation rating and a
higher plate voltage rating (450 or so), while the GB is rated at only 23
watts and 360 volts (as I recall, I don’t have a tube manual in front of
me right now). Anyway, the manufacturer’s ratings were conservative, and
a GB will handle 450 volts no sweat. But since it’s power handling is
lower, your amp will probably lose a bit of power. However, the Sovtek
5881s are very consistent and reliable. They also have decent tone.

Now as to what is better, a Sovtek 5881 is better than the Chinese 6L6, or
the Sovtek 6L6, yes. But they are in no way better than an old American
6L6GC. I’m sure the reason they want to sell you Rubys is because they
make a handsome profit on those boutique tubes. Be advised that Antique
will sell a matched pair of Sovtek 5881s for about $20. How much does
your shop want for the Sovtek 5881s that have been re-labeled by Ruby? A
Sovtek 5881 is a Sovtek 5881 regardless of who you buy it from. Save your
money.

Re-biasing is a very good idea, go for it, once the new tubes are
installed. However, insist that they use the current measurement method,
not the crossover notch method. Instruct them to bias between 30 and 35
milliamps per tube. The crossover notch method is total bullshit and is
not repeatable. It also results in overbiased, cold and harsh sounding
amps about 99% of the time.

Re-soldering the tube sockets may or may not be necessary. Did they state
why they want to do it? I know that the workmanship on those amps left a
lot to be desired, maybe they found some bad solder joints. I did in
mine. Go for it only to correct bad workmanship in the soldering, not
just for the hell of it so they can charge you more labor time.

Damn, I’m glad I do my own work.

Regards.