120v to 110v step down converter?
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Stephen300
Active Member
Take a look here...
https://robrobinette.com/5e3_Modifications.htm
Scroll Down to "Build a Bucking Transformer". I'm working on one now. My wall voltage typically runs around 122 to 124VAC. My lowered voltages with the BT turned ON were 109VAC and 115VAC on the two outputs.
https://robrobinette.com/5e3_Modifications.htm
Scroll Down to "Build a Bucking Transformer". I'm working on one now. My wall voltage typically runs around 122 to 124VAC. My lowered voltages with the BT turned ON were 109VAC and 115VAC on the two outputs.
Lavane
Lunatic Member
The problem is heater voltage. Its too high with power transformers with 110v primaries.
Lavane
Lunatic Member
Your right, a bucker would be cheap enough to build. I have a nice 6v, 6 amp transformer with a center tap.
FauxHall
Super Member
Since
Since heaters are a constant load, perhaps inserting a resistor in the circuit would help.
Since heaters are a constant load, perhaps inserting a resistor in the circuit would help.
Lavane
Lunatic Member
I've done that before with several old poin to point built console amps, etc., but these are built on printed circuit boards that are double sided with some of the traces buried.
I could take the preamps apart I guess. I would rather just be able plug them into something. The bucking transformer should do the trick. I have everytning I think except for a chassis box to put it in.
Stephen300
Active Member
In case anyone was wondering this is the Bucking Transformer I built.
Lavane
Lunatic Member
Nice build. I think I'll build one with two outlets on switches. Then I can switch between 7% and 12% on either outlet. Usually when modifying old console tube amps, or using old transformers for amp builds, I just adjust the dropping resistors. But I have bought a few pieces of equipment made in chinafilaments. PCB'S and 110v primaries. One phono preamp I was able to easily replace the resistors for the tube heaters to lower the voltage back down to 6.3v. But a couple others it's just a pain to remove the PCB's and find the traces buried in the boards.
The slightly raised B+ usually isn't a big deal, but raised heater voltage is hard on the filiments.
1924 popcorn
New Member
You selling any? I’ll take one or two.
You could get 7 high amperage bridge rectifiers and tie them together between the 120 volts and your intended 110 volts. Each rectifier (composed of 4 diodes) will drop the voltage ~1.4 volts. When you "tie them together" current can flow both ways, but you still get the voltage drop. You can easily get rectifiers rated to 25 amps cheap.
that doesn't make for an especially clean sine wave though. There will be about a half volt "gap" either side of the zero crossing where the voltage is below where the diode switches on. The switching I would expect to introduce some harmonics to the wave, not sure if it would be audible or not.
131east23
...near Frank's Pizza!
I love that!
I do it to drop the voltage for my train motors with no ill effects. It may be worth a try.
motors aren't audio gear though. AC motors don't love dirty power either, if you've ever heard the horrible racket that a ceiling fan connected to a dimmer makes, much of that is from the nasty switching from the triac. Thats at a much higher voltage though so probably more severe. Aren't train motors a universal series wound setup too? That type runs on AC or DC, so probably fairly un-fussy about what feeds it.
They run on dc.
