Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Oddvar on July 04, 2019, 12:56:36 pm

Title: PT Transformer choice
Post by: Oddvar on July 04, 2019, 12:56:36 pm

I am about to build a Trainwreck Express from parts that I mostly have in my drawer.  I have a Weber 40w and was wondering if I could use that.  What will I loose, is it possible? or any other idea for not using it?  I have enclosed a pic of it and a Classic Tone meant for TR Express.

I don't understand PT's much, so a good explanation would be nice

Title: Re: PT Transformer choice
Post by: sluckey on July 04, 2019, 01:05:45 pm

Here's a pretty good discussion by some trainwreck folks...

     https://ampgarage.com/forum/viewtopic.php?f=1&t=32132

Title: Re: PT Transformer choice
Post by: jbrew73 on July 04, 2019, 09:42:51 pm

Isn’t the OP the same in the amp garage thread?

Title: Re: PT Transformer choice
Post by: Tony Bones on July 04, 2019, 10:01:10 pm

Quote from: jbrew73 on July 04, 2019, 09:42:51 pm

Isn’t the OP the same in the amp garage thread?

Yes, no, doesn't matter. That thread answers all of the OP's questions.

Title: Re: PT Transformer choice
Post by: sluckey on July 05, 2019, 12:17:05 am

Quote from: jbrew73 on July 04, 2019, 09:42:51 pm

Isn’t the OP the same in the amp garage thread?

No, that's Oddvar R over at TAG.   :wink:

Title: Re: PT Transformer choice
Post by: MFowler on July 05, 2019, 12:03:50 pm

To get the correct plate voltage use the 300v HT taps.


The Express can be built with either 5k2 or 6k6 primary OT.


The PT & OT do not have to be rated for 300mA or 50W rating you can use lower mA or wattage ratings.


Try 6V6 tubes and you may have your perfect amp.


Mark