Mesa Rectoverb 50 Series 2 mystery mod

[GoneShootin]

Hi, it's been awhile. Haven't fiddled with modding, ect for a long time...

Well, I got a Mesa Rectoverb 50 Series 2 recently and decided to open it up and do the series loop mod. And I noticed that somebody pulled a leg of R39 (I think...it says 39 underneath it...could be a value) up and jumped it to pin 9 of V1. I'm a little rusty, what does this accomplish? Been searching and I'm having trouble figuring it out.

Thanks!

20220212_171850.jpg

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[pompeiisneaks]

Best guess is that the trace lifted, you can see it on the photo, so they hard wired it to repair it? (Pin 9 is the heater). From the schematic I'm attaching here, and the bands on that photo, it looks like a 39 ohm resistor, which matches this as the heater voltages sending out dc +3 and -3 V, so it does look like a repair. Maybe those burned up in a past tube failure or something similar.

recto.png

~Phil

[Stevem]

X2, that is not so much a mod but a repair for some reason.
That resistor is part of the Voltage balancing circuit on that DC powered tube.

V1 is the only tube set up to run on DC for a low noise floor.

[GoneShootin]

Thanks! That all makes sense now. Part of me wondered if that were the case, but I was so hung up on it being a mod that I pushed the thought to the side. Thanks again!