Bright channel weaker than normal channel, where to diagnose??

[dewman]

I have an old no name tube amp from the 60s. The normal channel is full and bang on- nothing wrong, but the bright channel is weak by comparison. I wonder if a preamp tube it the culprit? Any thoughts as to where to begin the diagnosis?

[boobtoob]

I have an old no name tube amp from the 60s. The normal channel is full and bang on- nothing wrong, but the bright channel is weak by comparison. I wonder if a preamp tube it the culprit? Any thoughts as to where to begin the diagnosis?

Just change the preamp tube(s) one at a time and check if it helps...if it doesn't...you have a spare tube...good to have a spare anyway.

I have an amp that is a 5e3 clone from the 50's. It has a normal channel and a bright channel. The bright channel has a single "tone" knob associated with it. If yours is the same, it could be that the associated tone knob is hooked up wrong or needs replacing.

[dewman]

Do you mean that the tone knob might not be connected in the right manner to the bright input? Could the input resistor cause signal attenuation if it was replaced with a less than optimal value (higher resistance)? I plan on tearing into it this weekend to check after I do the preamp tube swap.