New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

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brewdude
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by brewdude »

Is wound for a 110v outlet?
lightbath
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by lightbath »

Label on the transformer says "FBPP Tone Clone."

Thanks! As far as the switches I am doing some experimenting with cathode bypass caps, a gainstage / boost switch, and bright switches (trying to emulate the bright channel on a 6G3 using switchable caps, and possibly a blackface style bright switch depending on the tone stack I end up going with). I am pretty much treating this amp as a mod machine. Hopefully I will end up with something that sounds as good as a 6G2 but with some more premium features.

Note: I have an unused triode from the removed trem if anyone has any ideas.
Last edited by lightbath on Sat Oct 24, 2020 9:52 am, edited 5 times in total.
lightbath
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by lightbath »

The transformer diagram provided in the 3rd post says it is wound for 120V
lightbath
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by lightbath »

This may be unrelated to the transformer problem but I did notice the amp would make a popping sound and the volume would drop out (the low level hum would cease until the volume knob was turned back to the lowest position). When the knob was turned back down you could hear another pop and the return of the low level hum. The same was true for the tone knob but it would only pop and lose signal at the highest setting. The problem does not occur with v1 pulled. See video link below for details

https://www.youtube.com/watch?v=jVZLa4hwbUk

Is it possible this is caused by excessive voltage from the transformer on the plate and cathode, or does this sound like a separate issue? It seems as though the the first tube is getting hit with too strong of a signal when the volume is turned up slightly, and this is causing the tube to shut off / cease to pass signal.
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Phil_S
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by Phil_S »

That's interesting, but I don't think it is the cause of the voltage problem. You indicated the HT secondary unloaded is well above what can be expected, even if your input line voltage was 130. That pop is something else. I wonder if it is a bad pot.

I see you working on a live chassis with both hands free and you are using both hands. This is a decidedly unsafe practice. When you have a live chassis, one hand stays in your pocket at all times. This prevents the mishap of both hands completing a short circuit that runs right across your heart, which is potentially fatal. It's called an accident because you didn't mean to do it, even if you were being careful. Please change your work habits. This is no small thing.
lightbath
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by lightbath »

I have verified the pots are good. Checked all the wiring twice but the problem still persists. I just want to know if it is possible the high voltage could cause v1 or the knobs to behave this way.

Thanks for pointing that out Phil. I am aware of the danger but I will try to be more cautious when working around a live amp.
Stevem
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by Stevem »

Transformer V+ voltages specs are for the unloaded A/C voltage as the manufacturer has no idea if you will be using it with a high loss high impedance recto tube ( like a 5 Y3) or a low loss, low impedance tube like a 5AR4 and then how much circuit you will be tacking onto the output of the recto.

Your power transformer once again is bad, or wrong!
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lightbath
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Re: New Transformer - High Voltage AC Testing Way High - Princeton 6G2 Build

Post by lightbath »

UPDATE: Apparently they pulled the wrong transformer. They sent out a blackface Princeton transformer, instead of the brown, hence the higher voltages. I ended up building a brown Deluxe while I was waiting for the parts and it sounds great. The problem is the original Princeton build is still not functioning now that the new transformer has been installed. I still have no signal (only a low level hum) and the volume cuts out when turned up in the slightest.
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