Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: G._Hoffman on January 01, 2017, 04:58:08 pm

Title: isolate or ground a reverb send jack?
Post by: G._Hoffman on January 01, 2017, 04:58:08 pm

I'm building a single channel AB763, and I'm trying to decide if I need to ground the output jack for the reverb?  I'm kind of assuming not, since it is transformer isolated, and the return is grounded, so I'm kind of assuming that's the extent of what I have to do, but I thought I'd double check to make sure.

So, thanks in advance for any advice.


Gabriel

Title: Re: isolate or ground a reverb send jack?
Post by: PRR on January 01, 2017, 05:04:22 pm

It is transformer output so to a first approximation it does not matter.

The other side of the transformer gets 300V-400V DC. If the insulation breaks down, this appears on your RCA jack/plug. Basic safety would be to ground one end of the winding so when the paper goes bad the voltage can't go up, instead something burns and blows (+B dropper resistor) and leaves it electrically dead.

Title: Re: isolate or ground a reverb send jack?
Post by: sluckey on January 01, 2017, 06:31:01 pm

They were all grounded on the originals.

Title: Re: isolate or ground a reverb send jack?
Post by: G._Hoffman on January 01, 2017, 07:14:33 pm

Grounded it is.


Gabriel