DSL40c issue after mod. Hoping someone can help

[ledvedder]

Hi guys! I'm hoping someone can help me out. I performed the Headfirst mods on my DSL. Now I'm having this issue. Green channel works perfectly, but the red channel has very low volume and barely any gain. Any ideas where to start with diagnosing this problem?

Here's a video of the issue, https://youtube.com/shorts/IeZwQDqm2i0?feature=share

Here's a video of the mods, https://youtu.be/vMC_nrcwZGQ

Here's the schematic of the mods, https://img1.wsimg.com/blobby/go/525b4e ... 9282503943

[danman]

First thing that I would look for would be a bad solder joint. Obviously you should double check all of your work and wiring but I'm assuming you have already done that. Have you tried a fresh preamp tube in each spot to rule that out first?