Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: newguitarsmell on January 01, 2019, 03:04:50 pm

Title: Hum in standby dpst
Post by: newguitarsmell on January 01, 2019, 03:04:50 pm

Hi
I installed a dpst switch like Doug sells - I wired the PT and the AC on one side and split the connection from B+ to the rectifier on the other side (ht in and out). Bad bad buzz in standby - what did I do wrong?  :BangHead:

Title: Re: Hum in standby dpst
Post by: ginger on January 02, 2019, 11:41:50 am

You said " like Doug sells ".. is it the correct switch ?

Title: Re: Hum in standby dpst
Post by: ginger on January 02, 2019, 11:43:15 am

NO.. AC and PT on one side ... not DC

Title: Re: Hum in standby dpst
Post by: newguitarsmell on January 02, 2019, 09:53:06 pm

Yes. That's the switch. How to wire it Up? I got a bad hum on standby

Title: Re: Hum in standby dpst
Post by: PRR on January 03, 2019, 12:07:34 am

"Like" Doug sells? The one he offers for Standby is a Special, not any plain DPST.

Title: Re: Hum in standby dpst
Post by: ginger on January 03, 2019, 12:03:47 pm

Quote from: newguitarsmell on January 02, 2019, 09:53:06 pm

Yes. That's the switch. How to wire it Up? I got a bad hum on standby

  Black wire on power cord to AC IN....One of the PT primaries , probably BLACK , to PT  Primary.... rectifier to HV in.... HV out to 1st filter cap

Title: Re: Hum in standby dpst
Post by: newguitarsmell on January 04, 2019, 01:02:06 pm

Thanks ginger! That’s what I thought I did but evidently not!
I really appreciate all the advice...

and yeah - that Special DPST switch!

Title: Re: Hum in standby dpst
Post by: ginger on January 04, 2019, 02:49:52 pm

So ?

Title: Re: Hum in standby dpst
Post by: newguitarsmell on January 04, 2019, 07:03:12 pm

Haven’t tried to fix it yet...