Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 72Blazer on August 01, 2021, 12:03:29 pm

Title: 125P5DX Transformer Qs
Post by: 72Blazer on August 01, 2021, 12:03:29 pm: I've got this transformer and no documentation. I'd like to use this for a Fender Super Reverb Build.

I've got the pairs of Red, yellow, and green wires figured out.

It has a white wire and a black wire for 120V

The remaining wires are:

1 Orange
1 Blue
1 Purple
res
I think the blue and purple wiare for overseas power.

I guess my question is about the orange wire. Is this the 50V Bias?

Lastly will I need an artificial center tap.

Hoe this all makes sense.

Vr
J.
Title: Re: 125P5DX Transformer Qs
Post by: sluckey on August 01, 2021, 12:59:35 pm: Orange is typically connected to a shield but check for continuity between orange and any other wires.

Is there no red/yellow wire? Is there no red/blue wire? Is there no green/yellow wire?

Post a hi-rez pic that clearly shows every wire and it's color.
Title: Re: 125P5DX Transformer Qs
Post by: Electron Tornado on August 01, 2021, 05:04:52 pm: These might help:
Title: Re: 125P5DX Transformer Qs
Post by: Electron Tornado on August 01, 2021, 05:06:38 pm: Here's another
Title: Re: 125P5DX Transformer Qs
Post by: Electron Tornado on August 01, 2021, 05:07:26 pm: And still another
Title: Re: 125P5DX Transformer Qs
Post by: 72Blazer on August 03, 2021, 04:42:49 pm: Answers to Sluckey's questions:

Is there no red/yellow wire? No
Is there no red/blue wire? Is there no green/yellow wire? No

I got this info from the seller of the transformer: "The orange is the neutral wire on the primary; in the USA, this would be connected to the white wire of the mains.

The purple wire is the "hot"; on the primary for 120VAC, in the usa, this would be connected to the black wire of the mains.

The blue wire is the 50v secondary tap for a bias circuit."

I hand drew the wiring diagram provided by the sell
Title: Re: 125P5DX Transformer Qs
Post by: sluckey on August 03, 2021, 06:34:42 pm: If that's true then you should be able to measure resistance between the orange wire and the purple wire and the black wire. Is this the case?

But your drawing is a bit crazy. You show the white as a center tap for the high voltage but you placed the white at the end of the high voltage secondary??? You better use an ohm meter to verify.
Title: Re: 125P5DX Transformer Qs
Post by: 72Blazer on August 03, 2021, 08:01:57 pm: Good catch!

I flubbed up the drawing and also need another visit to the eye doc athough what I missed/did not include is bigger than Dallas. Here's the actual info for the PT.
Title: Re: 125P5DX Transformer Qs
Post by: 72Blazer on August 03, 2021, 08:04:55 pm: Resistance Orange wire and Purple is 9.7 Ohms
Resistance Orange wire and Black is 13.3 Ohms
Title: Re: 125P5DX Transformer Qs
Post by: 72Blazer on August 03, 2021, 08:07:48 pm: I have continuity between the orange, black, and purple wires. Does that check?
Title: Re: 125P5DX Transformer Qs
Post by: sluckey on August 03, 2021, 08:09:21 pm: yes
Title: Re: 125P5DX Transformer Qs
Post by: 72Blazer on August 03, 2021, 08:13:29 pm: Much appreciated. Learning curve is high ; )