Bottlehead Forum

General Category => General Discussion => Topic started by: PerroNegro on October 04, 2021, 01:07:35 PM

Title: George Wright AG 100
Post by: PerroNegro on October 04, 2021, 01:07:35 PM: My beloved AG phono has stopped powering on after burning 2 fuses. changed fuses and rectifier tube, but nothing. I just heard from a well regarded local and very professional repair shop that the (toroidal) power transformer is shot and it is custom and cannot be readily replaced. Aparently during a move, and unterminated transformer wire was dislodged and shorted. I guess I have 2 options- commission a custom transformer (no idea of the cost involved) or try to find a suitable transformer. Any one ever had this problem and care to share a solution?
Title: Re: George Wright AG 100
Post by: Doc B. on October 04, 2021, 01:52:13 PM: I'm looking at a picture of an AG100 on the usaudiomart.com website and it does not have a toroid on it. That doesn't mean a whole lot as George seldom built things the same way twice. The sticker on the transformer in the picture does make it look like it might have been something custom made for George.

https://www.usaudiomart.com/details/649387684-george-wright-audio-ag1000-preamp-wpp200c-phono-preamp-amp-wps04-power-supply/images/1678238/ (https://www.usaudiomart.com/details/649387684-george-wright-audio-ag1000-preamp-wpp200c-phono-preamp-amp-wps04-power-supply/images/1678238/)
Title: Re: George Wright AG 100
Post by: Paul Birkeland on October 04, 2021, 03:54:57 PM: If your transformer has that "HTS" sticker on it, that's Heyboer transformer. They can manufacture a replacement for you. You could also post some pictures of your unit, as the transformer in question could be something off the shelf, then again, maybe not.

I've worked on a few of George's pieces over the years since he has died, and they're all a little different.
Title: Re: George Wright AG 100
Post by: PerroNegro on October 11, 2021, 02:35:48 PM: The transformer was made by Toroid Tech. Cant get past just leaving messages on a recoding. But I cant figure out the voltages to a 12BH7 regulator circuit, so in order to duplicate the transformer. Anybody have any similar units? or know of the circuit/voltages the transformer works with?
I also found the diagram to the WP10-V, but its a different tube regulator from what I can see...
Title: Re: George Wright AG 100
Post by: Paul Birkeland on October 11, 2021, 02:37:43 PM: There's no winding labels on that PT?
Title: Re: George Wright AG 100
Post by: Paul Joppa on October 11, 2021, 03:33:15 PM: The pictures are too low-resolution to get much out of, but the circuit topology in the diagram is classic George. With better pictures, and answers to a few questions, a good guess of the operating voltages can be made, and specs for a suitable replacement determined. What are the tubes in your preamp?

Antek makes a variety of toroid power transformers for tube circuits. Probably there is one that is suitable. What is the diameter of your toroid?
Title: Re: George Wright AG 100
Post by: Paul Birkeland on October 11, 2021, 04:00:32 PM: Quote from: Paul Joppa on October 11, 2021, 03:33:15 PM
What is the diameter of your toroid?
Leave it to PJ to ask those deeply personal questions ;)
Title: Re: George Wright AG 100
Post by: Doc B. on October 12, 2021, 07:37:58 AM: I had the prototype WPL10V. It didn't have a toroid. That was a zillion years ago. Not sure what George used for a transformer. Usually it was something from his surplus stash.
Title: Re: George Wright AG 100
Post by: PerroNegro on October 14, 2021, 07:59:09 AM: This is the only other photo I have at the moment. The unit is at the shop, and I will try to go by and take some photos. The transformer was made by toroidal tech, we are unable to get any response from them over the last week. :-[
Title: Re: George Wright AG 100
Post by: PerroNegro on October 14, 2021, 08:18:14 AM: The label does not include secondary voltages, only primaries (120VAC, 50/60Hz 72 VA)
The rectifier is a 6x4 and the ECC99 regulator? in the PS