Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Diverted on December 26, 2018, 08:04:26 am

Title: Hoffman Revibe power transformer
Post by: Diverted on December 26, 2018, 08:04:26 am
Hi,
I'm going to buy a Hoffman board for the revibe and give it a try. I have a question about the power transformer. I have a NOS unused Stancor PC8403 transformer on hand and am wondering if it can be used. HV secondary is 250-0-250@70ma, with a 2.5a 6.3v winding. Heater winding should be fine; can I just use a full wave bridge rectifier with this center tapped winding? If I'm right this should give me around 350v rectified?

Thanks, and Merry Christmas!
Title: Re: Hoffman Revibe power transformer
Post by: sluckey on December 26, 2018, 08:13:43 am
Quote
can I just use a full wave bridge rectifier with this center tapped winding? If I'm right this should give me around 350v rectified?
No. A FWB w1ll give you 700V.

That PT will be fine if you just use a conventional full wave rectifier (NOT A BRIDGE!)
Title: Re: Hoffman Revibe power transformer
Post by: Diverted on December 26, 2018, 09:11:39 am
Thanks Sluckey. Will probably end up using a GZ34 rectifier with it then?

Title: Re: Hoffman Revibe power transformer
Post by: sluckey on December 26, 2018, 09:23:01 am
Not with that PT (unless it has a 5V winding). I would just use two 1N4007s.
Title: Re: Hoffman Revibe power transformer
Post by: Diverted on December 26, 2018, 09:29:51 am
Oh, I'm sorry. Yes it does have a 5V winding. So, you were just referring to a diode off each outer leg of the HV secondary, terminating together, with center tap to ground? That would be much easier!
Title: Re: Hoffman Revibe power transformer
Post by: sluckey on December 26, 2018, 12:01:11 pm
Oh, I'm sorry. Yes it does have a 5V winding. So, you were just referring to a diode off each outer leg of the HV secondary, terminating together, with center tap to ground? That would be much easier!
yes