• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

How can I turn 120VAC to 100VAC for Tango MS-UVD in an 845 SE amp?


2010-06-06 8:17 pm


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I see that I would need a separate transformer.

My main voltage is 124V. Seems like I would need a transformer with 24V secondary. What about the primary voltage?

Could you guys tell me where I can get a good transformer?

Current transformers intended for the U.S. market generally have 120V primaries, no real choice here. Anything in the 20V - 24V range is going to work fine.. You haven't mentioned what the current consumption of this amplifier is on 100V - that is a part of the puzzle that is missing, and I usually like to chose a transformer that is rated at twice the maximum current I will use it at for this sort of application.

Antek makes toroids that are pretty good for this application for very reasonable money.. Digikey, Mouser and Allied Electronics also sell a variety of transformers that would be well suited for this application.


2010-06-06 8:17 pm
I haven't measure the current of this amp. I need to replace the fuse on my meter. The amp is an 845 SE so I suspect that it draws about 300w or 3 amps.
I will measure the current when I get the fuse. Assume that it draws 3 amps, what is the current of the transformer I should get?
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