Help with Supex step-up transformer modification

sl-15 · 187

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Offline sl-15

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on: September 08, 2024, 06:14:54 PM
Hi, I recently got a Supex SDT-3 step-up transformer. I could not find any specifics online but it works great with my Supex SDX-1000 cartridge. (Anyone who knows about this transformer please let me know) The unit has a bypass switch built in. I guess the idea was to be able to swap in a MM cartridge and not have to change cable configuration. The switch is a bit finicky with the signal going in and out and probably needs a good cleaning. Also the solder joints inside look rather aged. I have no use for the bypass switch and think the easiest thing is to just bypass the switch. This should be easy to do by just connecting the cable coming out of the transformer directly to the RCA instead of the switch and disconnecting the cable from the switch to the RCA. Please refer to the photos for clarification. Any downsides in doing this that anyone can think of? My thinking is that a direct connection, bypassing the switch, would be better sonic wise and I have no need for the switch anyways. Curious to hear if i am on the right track with this or if bypassing the switch would be the wrong thing to do. Thanks for your thoughts.

Stefan Hampel
Soundsmith Carmen, modded Technics SL-1200mkII, Thorens TD 125 mk2 with SME V, Eros, Extended Foreplay III, BeePre2, Crack, Pioneer Spec 4, Sonus Faber Electa


Offline Thermioniclife

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Reply #1 on: September 09, 2024, 03:14:13 AM
That looks like a vintage piece of gear, I would give the good flushing out with contact cleaner and call it a day. You might want to sell it someday and
keeping it original would be the way to go.

Lee R.


Offline sl-15

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Reply #2 on: September 09, 2024, 06:47:15 AM
Thanks. It is definitely vintage I am guessing early 80ies. I thought about the resale value as well. Keeping it original would be better but it also could be easily converted back to its original form.

Stefan Hampel
Soundsmith Carmen, modded Technics SL-1200mkII, Thorens TD 125 mk2 with SME V, Eros, Extended Foreplay III, BeePre2, Crack, Pioneer Spec 4, Sonus Faber Electa