Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on April 24, 2022, 08:15:29 am

Title: Presence circuit difference by 1 resistor
Post by: pbman1953 on April 24, 2022, 08:15:29 am

I have the '75 Super Twin amp. I'm still using it as a bass amp. When I first started working the amp I noticed that my board parts are somewhere between both versions. My version doesn't have reverb. I guess some items on the Reverb unit were corrections from the ST.


In the eq area there is a one part difference between the two versions. The ST has a 470 ohm resistor in the circuit and the ST Reverb doesn't.


What kind of difference would that make? At the moment I don't have my out to see but I will soon.


I'm curious what the resistor is doing. Over all the control doesn't do  much but it's supposed be located around 4k.


Thanks

Title: Re: Presence circuit difference by 1 resistor
Post by: sluckey on April 24, 2022, 09:02:30 am

I'd say there is not enough difference to hear or even talk about.

Title: Re: Presence circuit difference by 1 resistor
Post by: pbman1953 on April 24, 2022, 09:03:30 am

cool, thanks