Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: worth on April 18, 2011, 11:47:52 am

Title: Hammond 125ESE wiring ?
Post by: worth on April 18, 2011, 11:47:52 am: For this single-ended transformer there are two primary wires , one blue , one brown. Which wire goes to the B+ , and which goes to pin 3 of the output tube ?
Title: Re: Hammond 125ESE wiring ?
Post by: bobmegantz on April 18, 2011, 12:03:40 pm: First, make sure that those are the primary leads - I had a Hammond SE xformer that had multiple primary taps and 2 secondary wires, where you chose the primary taps for the desired output impedance (or am I tripping?).

If they are indeed the primary leads, it doesn't matter, except the phase will switch. If you're using NFB, you need to wire it so that the feedback phase is correct.
Title: Re: Hammond 125ESE wiring ?
Post by: worth on April 18, 2011, 12:11:59 pm: Yes.. those are the primary leads. I DO have negative feedback, ( 5F2A) , that's why I'm asking.
Title: Re: Hammond 125ESE wiring ?
Post by: phsyconoodler on April 18, 2011, 12:27:29 pm: Blue goes to pin 3 of the power tube.
Title: Re: Hammond 125ESE wiring ?
Post by: VMS on April 18, 2011, 12:38:56 pm: In my amp brown wire goes to pin 3 of the power tube.

Test before you cut those wires too short.
Title: Re: Hammond 125ESE wiring ?
Post by: RicharD on April 18, 2011, 12:45:05 pm: Either way will work. Depends on if you want the transformer to invert or not. With NFB, if the amp squeals, reverse them.
Title: Re: Hammond 125ESE wiring ?
Post by: sluckey on April 18, 2011, 12:45:16 pm: Quote from: worth on April 18, 2011, 12:11:59 pm
Yes.. those are the primary leads. I DO have negative feedback, ( 5F2A) , that's why I'm asking.
Just temporarily connect it and be prepared to swap leads if negative feedback is wrong.
Title: Re: Hammond 125ESE wiring ?
Post by: RicharD on April 18, 2011, 12:54:49 pm: CRAP ALERT!

Stay off the hammond mfg website. I just got bombarded with dirty cookies when I went to check the wiring diagram.
Title: Re: Hammond 125ESE wiring ?
Post by: worth on April 18, 2011, 01:46:00 pm: I was hoping to avoid the annoying squeel.... but I guess I'll just have to temporarily connect the leads.