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Hoffman Amps Forum image Author Topic: Toggle Switch for PT secondaries  (Read 2519 times)

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Offline 66Strat

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Toggle Switch for PT secondaries
« on: March 06, 2020, 01:14:00 pm »
I have a power transformer with 275-0-275 and 325-0-325 secondaries. I want to place a switch between the transformer secondaries and the rectifier. I would prefer an On-On (break before make) switch but an On-Off-On switch would suffice. Will the Lamb ST switch that Doug in his catalog work?
Regards,
JT

Offline sluckey

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Re: Toggle Switch for PT secondaries
« Reply #1 on: March 06, 2020, 01:21:15 pm »
Yes, it will work just fine. I'd rather have a DPDT ON-OFF-ON. Center would be standby.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline 66Strat

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Re: Toggle Switch for PT secondaries
« Reply #2 on: March 06, 2020, 01:25:51 pm »
Thank you! :thumbsup: Is Doug's switch a 3 position switch?
Regards,
JT

Offline sluckey

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Re: Toggle Switch for PT secondaries
« Reply #3 on: March 06, 2020, 01:29:37 pm »
Thank you! :thumbsup: Is Doug's switch a 3 position switch?
Doesn't so it is so I would assume NO. A pm to Doug would confirm.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline pdf64

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Re: Toggle Switch for PT secondaries
« Reply #4 on: March 06, 2020, 01:39:29 pm »
If using a tube rectifier, that would be a ‘less than ideal’ method of arranging standby (as it’s hot switching).
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Offline sluckey

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Re: Toggle Switch for PT secondaries
« Reply #5 on: March 06, 2020, 01:59:33 pm »
If using a tube rectifier, that would be a ‘less than ideal’ method of arranging standby (as it’s hot switching).
I disagree.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline 66Strat

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Re: Toggle Switch for PT secondaries
« Reply #6 on: March 06, 2020, 02:06:27 pm »
Thank you! :thumbsup: Is Doug's switch a 3 position switch?
Doesn't so it is so I would assume NO. A pm to Doug would confirm.

Thanks. PM sent.

If using a tube rectifier, that would be a ‘less than ideal’ method of arranging standby (as it’s hot switching).

I agree that hot switching is not a good thing with tube rectifiers. But I don't know if it makes that much difference if the AC is switched going into the rectifier or the DC coming out. IME, if the filter caps have enough time to drain, it would stress the rectifier in either situation, if the tubes are still hot. My goal is to switch between two AC voltages.
Regards,
JT

Offline pdf64

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Re: Toggle Switch for PT secondaries
« Reply #7 on: March 07, 2020, 10:35:04 am »
...I don't know if it makes that much difference if the AC is switched going into the rectifier or the DC coming out. IME, if the filter caps have enough time to drain, it would stress the rectifier in either situation, if the tubes are still hot. My goal is to switch between two AC voltages.
I don't think it makes any difference whether the switch is on the plate or cathode side of the rectifier, the exact same current is being switched, hot switching a discharged reservoir cap will result in high peak surge currents through the rectifier either way.
To switch between the 2 HT winding voltages, I suggest it's best to do so when the amp is off.

If using a tube rectifier, that would be a ‘less than ideal’ method of arranging standby (as it’s hot switching).
I disagree.
I'd appreciate it if could you expand on that  :w2:
https://www.justgiving.com/page/5-in-5-for-charlie This is my step son and his family. He is running 5 marathons in 5 days to support the research into STXBP1, the genetic condition my grandson Charlie has. Please consider supporting him! BBC News feature  https://www.bbc.co.uk/news/articles/cm26llp

 


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