Technical understanding

[txstrat]

Just for my knowledge.
Due to a broken power tube (internal arcing) I pulled that tube out of my two 6V6 PP amp and disposed it.
Well, the amp is playable with one tube as well (haven't pushed it, cause it's just for living room use).
Will it hurt or stress the OT or remaining tube too hard if I leave it that way?

Thanks

[Brad1]

I wouldn't play it like that. It's designed for a pair of tubes to work properly. Buy a new set of tubes.

BTW, it's even more helpful to provide more relevant info...such as make and model of amp...to get more relevant answers, and possible workarounds.

Brad1

[redelephant]

The one leftover tube turns the output into a single-ended type. The OT is made for PP operation and therefore has no airgap and will probably saturate in the low frequencies. I don't think much damage will be done other than the amp possibly farting out at the low end. If this were a high power brute I'd be careful, but my guess its a 15-20watt type? If the idle is high enough u can get a few clean watts that way, but it will quickly reach a point where the tube cuts off at the negative going cycle, and without the other tube picking up where the first lets go, u'll have serious assymetric output. Maybe not bad for some styles, it should get real thick and muddy when that happens.

U should have much more noise from the power supply. Any such issues?

Be aware that when the OT saturates, the tube sees a very hefty load...Don't sue me if it blows up, but that wouldn't stop me from using it like that. (I'm not the careful type, so u decide for ur self).

[txstrat]

I've played the amp just for a couple minutes and it was at living room level. So far the amp didn't fart out. Actually I didn't notice any difference. I don't mean to play it any louder (at least not with a missing tube).
It's a copy of a brown 6G3 Deluxe amp I built from scratch; running at 30mA.

BTW you can see it in my current avatar. Nice piece of furniture as well.

[redelephant]

BTW you can see it in my current avatar. Nice piece of furniture as well.

Very nice indeed



Btw, I don't think it damages the amp any more playing loud, b/c it's the DC current thru the ungapped OT that has potential for damage. The unloaded primary might cause problems. U could load it simply by placing a resistor on the unused primary to gnd. If u use a value that draws 30mA u'll be safe for sure, but even half that is probably plenty. But we're talking a large power resistor now. Mesa Boogie does the trick of turning the output into a class-A single-ended deal by simply muting the input to one side of the PP pair, so the unused tube is still drawing the same DC current and u end up driving SE but with no problems due to no airgap.

[Steve Conner]

If the amp is cathode biased, the remaining tube will be run far too hot.

[txstrat]

The amp's fixed bias, but thanks for the hint, Steve.
My question was mainly to know if it's save for the amp to use it that way (as long as I wait for new tubes). I'm gonna buy a new set of tubes soon, anyway.

BTW it don't make any more noise with a missing tube. Amps still dead quiet.