Ampeg GV-22

[Denton]

Hangman, you are the man. Mystery solved! Well, I guess I need to figure out what tap was used, but at least I know what I'm dealing with now. What's strange is that the speakers were wired to 16.

[Steelyman]

right.... there is also a 2 ohm tap. But there are also 4 and 8 ohm taps, and it is unlikely that whoever replaced the output transformer used the 2 ohm tap. but perhaps you should check on it.

http://www.mojotone.com/amp-parts/amp-tr...Kysg8aZa-I

its basically that transformer.

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I'm holding one of those transformers in my hand. So you gotta believe me.

Now that the OT had been identified, you can rewire the speakers in parallel for 4 ohms using the yellow 4 ohm tap. Without a 16 ohm tap for the feedback loop, just connect the feedback to the 8 ohm tap and increase the 15K feedback resistor to 27K. It's all reversible if you decide later to get another OT with a 16 ohm tap. But you can wail on safely for now.

[Denton]

I am not a tech (obviously).. But Hangman, do you know which colors on the Fender OT you have in your hand is what? If so, is there a way I can just open it up and look inside to see what tap mine is using?

If I wasn't in the middle of packing and moving, I would open mine up and take some pictures to post. At this point, I can't. Plus my wife was not happy that I spent like 4 hours cleaning, changing grill cloth, etc on it last Saturday while she was packing

[Steelyman]

Denton, I sent you a link to the wiring diagram for your OT. Check your email

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or...

Link to the wiring diagram for your OT.....

http://www.mojotone.com/transformers/Fen...OJO774.pdf

[Denton]

Looking at the colors of the OT Hangman is holding, they seem to be brown, red, and purple. The Mojotone shows green, yellow, and brown?

Without my wife looking, I'm going to try and pull the amp out of the moving pile and see what color wires mine has.

[Steelyman]

[quote='Denton' pid='1128' dateline='1420657330']
Looking at the colors of the OT Hangman is holding, they seem to be brown, red, and purple. The Mojotone shows green, yellow, and brown?

I believe those are the Brown/Red/Blue Primary wires. The hues are a bit off. It's common that the Secondary (speaker) wires are usually Black for Common and just about anything but Blu/Red/Brn for the taps. I hope the unused taps aren't cut off.

[Hangman]

yes those were the primary wires. the other end has the exact same color scheme as the monotone.

[Denton]

Awesome. Won't have to go to the shop now

Thanks!!!!

[Hangman]

It sounds like you wont be needing this... but since I think it is interesting I thought I would post it anyway.
I wrote to Heyboer a few days ago to ask if they have a remake of the GV-22 output transformer and here is what they replied:

"Steve, hello.
Yes, the transformer for that model is the OT-215. Now, depends on how close you want it to original.
We have an exact clone on file ,HTS-5228 from a reverse engineered take down. Is very involved winding , with 7 sections , Primary is 32 ga wire ran parallel for the most part. OR Fliptops has our HTS-7668 http://www.fliptops.net/catalog/p-100604...-gemini-ii
is same pattern but a bit larger wire so not an many sections in parallel. taken to 3 primary and 2 secondary sections. Mfg one pc of exact clone would be $185. one pc wound as Fliptops $135."

The prices were higher than I expected, but not by much.

interesting to hear what he had to say about the original transformer. I have seen a number of those with dead output transformers... I wonder if that has anything do do with the parallel 32 ga wire. seems like a very thin gauge wire to put in a transformer like that. but then.. I'm not really experienced with winding transformers.

[Denton]

Very interesting information and insight. If my current Fender OT is acceptable, I'll stick with it. I'm anxious to get a chance to open it up to see how mine is wired.

Thanks