Model T pre-amp question

[mike_sims]

The Normal volume on one of my Sunn Model T's (vintage, not reissue) sounds really low and my bright volume sounds incredibly loud (when plugged into Both IN). Could this be a pre-amp tube issue?

[tacklebox455]

sounds more like a bad pot issue or loose solder on connection

[loudthud]

Does the Normal volume sound louder when you plug into the Normal Input jack? That would indicate a faulty jack that does not conduct the signal from the Both jack as it should. You can swap the preamp tube closest to the input jacks with the one in the middle to see if the tube is the cause of the problem.

[mike_sims]

Does the Normal volume sound louder when you plug into the Normal Input jack? That would indicate a faulty jack that does not conduct the signal from the Both jack as it should. You can swap the preamp tube closest to the input jacks with the one in the middle to see if the tube is the cause of the problem.

exactly! That makes a lot of sense actually... So could it be the Jack itself going bad? Or maybe just a loose/bad connection between the Normal Jack and the Both In Jack? Thanks for clearing that up!