TMB channel always active?

[Returnsnull]

When I’m using the normal inputs (either) of my
Mojotone 18W TMB, I have a large amount of background static (whooshing air) that is eliminated by turning down the TMB channel master volume.

Turning the T/M/B knobs affects the whooshing.
The gain knob affects it as well.
It happens with or without a guitar plugged in.
I can still hear the guitar through the normal channel (although it seems to live behind the whooshing and the guitar signal gets louder / more upfront when the MV is turned down on the TMB channel.

This makes me believe the problem must exist before the first TMB tone stack and that the inputs aren’t the problem.

I don’t understand what “turns off” the TMB channel from looking at the layout so that leads me to believe that nothing turns it off and the problem is that my TMB channel is a little noisy.

This is how I currently have the inputs wired although I’ve tried 2-3 setups. I’m fairly convinced the input isn’t the issue but I’m also convinced I don’t know what I’m doing so...

9417AB31-CDD6-4840-A8D7-F19D25477FC6.jpeg

I’m lost and would love any suggestions.

[geoff 1965]

hello,
i can't see your grid stopper for the TMB channel?

[Returnsnull]

Oops! Sorry, two variations from the picture I posted:

I have the normal channel going to pin 2 and the TMB channel going to pin 7 and I do have a grid resistor for the TMB channel, it’s wired in the same way as the normal channel (mounted on a terminal strip).

[geoff 1965]

it look's like you've got your grid inputs the wrong way round,the TMB input should go to pin 2 with the .68uf cathode capacitor "pin 3" and the normal channel goes into pin 7 with the 47uf cap from pin 8.
can you add a close-up pic of the wiring to V1?

[Returnsnull]

Well, I would post a picture but after I tried swapping the normal and TMB with no change, a sudden gust of frustration swept through the workshop.

09D77E21-F3D2-4E90-AAC2-6DB512C4FEA8.jpeg

Wiring was messy before. Going to try to do this a bit nicer and try it again.