Use of HI-FI transformer type vol. control as attenuator ?

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chopstuck
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Use of HI-FI transformer type vol. control as attenuator ?

Post by chopstuck »

I remember Loy Dockery showing me his quick and dirty attenuator made from a stereo wall mount 100 watt control with two built in transformer cores.
Seemed to work but I'm not sure about flyback voltages reflected load and - did I mention I just lost that nice little Bogen SE OT to an impedance mismatch ?

It did sound pretty good on his Spitfire clone but how about longevity ?
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Colossal
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Re: Use of HI-FI transformer type vol. control as attenuator ?

Post by Colossal »

The Radio Shack L-pads and similar in-wall mount attenuators seem(ed) to be popular fare over on 18watt.com. Loy was active over there for a time. I have no experience with them (save having them in each room for my home stereo). I have read that some guys say they sound good with their 18 watt derivatives, others say they sound terrible. Internet opinions always seem to leave you with more questions than answers. I can't recall reading anything about failure of these units or the death of output transformers as a result of their use. My application is Class D mosfet transformerless type stuff for the home stereo so the impedance mismatch might not be an issue as it is with guitar amps.

The Marshall Power Brake is a big multi-tapped inductor and from what little I've studied about the in-wall mount attenuators, they look very similar. Sorry that's not of much use.
rock_mumbles
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Re: Use of HI-FI transformer type vol. control as attenuator ?

Post by rock_mumbles »

I bought one of the mono 25 watt Radio Shack ~$20 wall attenuators ... it was horrible then I found this ...
http://www.charlestongolf.com/lineout/p ... nuator.htm
Added the 4 ohm resistor and now it works ...
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roberto
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Re: Use of HI-FI transformer type vol. control as attenuator ?

Post by roberto »

http://www.charlestongolf.com/lineout/i ... nuator.jpg
Can be used also a small variac with the right impedance, and a toroid material able to manage the audio frequency?
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