Can anyone aid in identifying this amp??

[g1]

If it's clipping at all that means the output tube is putting out all the clean power it can.

And if the 6SL7 is delivering a weak clipped signal?

[Chuck H]

Possible. I did qualify that a little by indicating the preamp voltage. But if the bias on the preamp tube is way off or it's otherwise operating poorly, who knows?

I would probably go through it and replace old electrolytics, check film caps for leakage and resistors for value drift, confirm relative goodness of the tubes, clean contacts, etc. Then, if it's still not performing we would need voltage readings. But I would go through the amp first. Voltage readings don't mean much while multiple components and tubes could be bad.

[Resonator Guy]

Folks, I don't think the thing is clipping as it just sounds too good. The tubes test out almost as strong as NOS, so I will start replacing a few bits and see what happens. I don't believe the problem is any of the filter caps as the amp is dead quiet. There are a number of other things I will check.

[Resonator Guy]

Although this thread started as me looking for the maker of this amp, it soon became a discussion on its low volume. I think I have cracked it.
At some time in the past, someone added speaker leads of thin wire that were well over a foot long. I don't know why. Close inspection revealed that both wires had rested against something very hot - not inconceivable in a tube amp - and both had exposed sections with the insulation melted off. I trimmed these to a more manageable length and reconnected the speaker. I got at least twice the volume. It doesn't require ear plugs but now sounds more like it should. So it is an instrument amp as I thought, not an amplified speaker( but then what is an instrument amp but an amplified speaker).
I will continue my efforts to tidy this up, but it is well on the way now.

[Chuck H]

Time and pressure That's how most things happen. Great discovery on the speaker leads. Though I wonder how exposed insulation on speaker leads could cause low power. I would expect a bigger problem or no problem. Weird things happen sometimes though. The more you fix/restore the better it will get. Is there a code on the speaker rim?

[km6xz]

I would do as little as possible to it, and if you really want a playable amp, it is worth more to people who value anything with the term "vintage" preceding the name. If so you could trade or sell it for more than a decent amp would cost. If you start swapping out old parts, just because they are old, it will not have any value. If the gain is low, find out why, maybe a cathode bypass or leaky coupling cap but if it is hum free and sounds clean it is probably fine as is.
It is still most likely a remote speaker for any number of possible uses like projectors or small pa. You can tell by measuring the frequency response, the remote speaker amp would have a relatively flat response and an instrument amp will have a hf de-emphasis. The really old amps were not as often guitar amps in the normal sense but when this one was built, steel pedals and Hawaiian lap steel guitars were the main use of them. Line level varied a lot at first so gain is not a good indicator of its intended use.

[Resonator Guy]

Chuck, fixing the speaker leads confused me too, but it really did improve the sound. I would think if they were shorting out there would be no sound. There is no code on the rim of the speaker so I can't tell who made it or when. 8" 4 ohm is all I know. km, I am sure it is a lap steel amp and will fit nicely with others I have. I will only be changing what is necessary.
It is sounding and looking pretty good now.

[g1]

Just a guess that the exposed speaker leads were either touching each other or the chassis. Some dirt or oxidation would result in low resistance rather than a "dead short" (which would have stopped the sound completely).

[Resonator Guy]

Probably so g-one, because, before I noticed the exposed bits, I stretched the leads out to hook up to a 12" old Jensen and it sounded damn fine, so I guess they weren't hitting anything then. I have disconnected that added RCA jack, cleaned things up and am ordering a few parts, but right now, it pretty much done.