Bassman 6g6-b low output in one channel

[Tonegeek]

I have a '64 bassman (6g6-b circuit). This is the one with the bass and mid controls after a cathode follower, followed by a tube buffered treble control. My question is this: Should the output levels of this "Bass" channel be about the same as the output of the "Normal" channel? Just trying to determine if I have an issue. On my amp, the Bass channel output is quite a bit lower than the Normal channels output. It is very clean and won't break up like the normal channel. Might be designed this way, but I can't tell by looking at the schematic. I naturally favor the normal channel as is but it appears there could be some good tone to be had from the bass channel as well, so I am thinking the low output is not normal.
thanks

[Structo]

Do you have the same tubes in V1 and V2?

I would be swapping tubes around to rule those out.

[Firestorm]

Yeah, try swapping new (or known good) tubes into V1 and V2 (those are both for the Bass Channel). And make sure you've got good bypass caps on V1 and V2 (only 2 bypass caps, because V1 has a cathode follower circuit and one triode of V2 is unbypassed).

That said, the next thing to watch out for in these amps is the .25 caps in the tone stack and the .1 cap between the sections of V2. If those are still the original Astron caps, it's a good bet that they are leaking significant DC. I saw a .25 Astron in a 6G6B that was passing over 20 volts DC!

And then there's the tone stack itself. Really the wackiest thing Fender ever did. Plug the values into Duncan Munro's Tone Stack Calculator and you'll find that the signal is almost -50dB down at 110Hz, -36dB at 1K and -23dB at 5K. So, yes, low, clean output was part of the design. There were absolutely no good, powerful bass speakers available when this was built.

[Structo]

If you look at the schematic you will see that the bass channel has an extra tube in the preamp, resulting in more gain.

The bass channel has a cathode follower tone stack and the normal channel has a plate loaded tone stack.
Kind of a strange design really.

So not sure if it is the tone stack causing your loss of gain or what.

I haven't played through one of those classics so I'm not sure if you have a problem or if that is just the way those amps roll.

http://www.schematicheaven.com/fenderam ... _schem.pdf

[6G6]

Both channels should have about the same output.
The bass channel is intended to be very clean.

[Structo]

Heheheh, with a username like that, I assume you know this circuit quite well?

[Tonegeek]

Both channels should have about the same output.
The bass channel is intended to be very clean.

I was thinking that might be the case. Guess I will sub some tubes in and go from there.
thanks to all