Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: hylaphone on October 13, 2025, 01:07:30 pm

Title: Hot Rod Deluxe strange issue
Post by: hylaphone on October 13, 2025, 01:07:30 pm

Hi folks, I have a HRD here with ongoing static noise issues. I've isolated it to V2, seeing between 1 and 2VDC on both grids of the tube. There is also <1VDC on the TMB pots. Leaky tonestack cap would explain DC readings on pin 2 but I'm having a hard time visualizing what would cause the same on pin 7 as it's not present at the C2/R18 juncture.Trying to wrap my head around this before pulling the PCBThank you!https://el34world.com/charts/Schematics/files/Fender/Fender_hotrod_deluxe.pdf (https://el34world.com/charts/Schematics/files/Fender/Fender_hotrod_deluxe.pdf)

Title: Re: Hot Rod Deluxe strange issue
Post by: DeepBias on October 13, 2025, 06:50:14 pm

Before pulling the PCB have you tried with another 12AX7.

Title: Re: Hot Rod Deluxe strange issue
Post by: hylaphone on October 14, 2025, 05:05:21 am

Quote from: DeepBias on October 13, 2025, 06:50:14 pm

Before pulling the PCB have you tried with another 12AX7.

Yes, no change