Transformer switch

johnsonad · 2450

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Offline johnsonad

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on: June 03, 2013, 04:10:00 PM
I'm really happy with my modified S.E.X. for the Stax headphones but I would like to use it with my speakers also.  Logistically I can get both pair of transformers to fit though not ideal.  I was thinking of using a 4PDT switch, one for each channel to switch between the two sets of transformers.   Of course I would switch when the power was off.  First would someone tell me if I'm crazy for trying this and if it's possible without major issues, could you recommend a good switch?  I found this one on Mouser but am unsure if it will met the voltage:

 http://www.mouser.com/ProductDetail/NKK-Switches/S42-RO/?qs=sGAEpiMZZMvudeGI7i40XG0UpOd5pEJjRu%252bM6rGT5fw=

Aaron Johnson

Offline johnsonad

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Reply #1 on: July 28, 2013, 09:49:22 AM
Time for a bump. I know this isn't ideal but if I did it while the amp was switched off it seems like it would be okay. Am I wrong? Thoughts on a good switch to make this work?

Aaron Johnson

Offline Paul Joppa

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Reply #2 on: July 28, 2013, 11:37:25 AM
I'm not clear what you are proposing. But it seems to me that you can leave the secondaries attached (one set to the headphones, the other set to the speakers) and leave the "cold" primary connected to the power tube cathodes, then switch the parafeed cap to one set of transformers or the other. A single DPDT switch would do that, in stereo - or a SPDT for each channel if it's more convenient to install the switches far apart.

Because the parafeed cap is between the high voltage and the transformers, the switch does not need to handle any DC voltage, and if the amp is off there will be no signal voltage either - so pretty much any switch would be fine.

Unless I have misunderstood your question?

Paul Joppa

Offline johnsonad

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Reply #3 on: July 28, 2013, 12:02:17 PM
Thank you Paul! That makes sense! What AC voltage rating would you recommend for the switch?

Aaron Johnson

Offline johnsonad

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Reply #4 on: July 28, 2013, 02:31:36 PM

Aaron Johnson

Offline johnsonad

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Reply #5 on: July 30, 2013, 01:26:52 PM
A small bump ;)

Aaron Johnson

Offline johnsonad

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Reply #6 on: August 01, 2013, 02:21:27 PM
No luck. Had a EE buddy of mine give me the okay and ordered a pair of these switches. I'll post the results in my other S.E.X. thread

Aaron Johnson

Offline Paul Joppa

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Reply #7 on: August 01, 2013, 06:44:00 PM
It looks perfectly satisfactory.

Sorry, I rely on the "Show unread posts since last visit" link, and it doesn't seem to pick up everything I missed - I only now saw this follow-up. Usually I will go through the sub-forums every week or two to pick up the missing ones, but even then a few slip through.

Paul Joppa

Offline johnsonad

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Reply #8 on: August 02, 2013, 01:04:09 AM
Paul you do more than any designer I know of for their customers. Thank you! If a question or two falls through the cracks every now and then I can live with that :)

Aaron Johnson

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