100v stepdown

I’m considering a Japanese amp that only comes in 100v. What would you advise/ recommend with regard to a stepdown?

Have you considered a transformer?

Noooo, tell me more…

Just get one of our expert repair chaps, to replace the input transformer, for not much more, than a stepdown.

If you’re planning on buying random Japcrap, then getting your own decent step-down would make sense, otherwise the cat can do no wrong.

I don’t think I’d go down the regenerator route personally.

I’m really looking for pointers on whether and where to buy a good step down from, or failing that who might build one. Any specs to note based on using it for an amplifier etc.

Remember that Japan is 100V. Many will step down to 110V, or expect 230V. My voltage usually measures closer to 250V than 240V, so stepping it down 1:2 would only get it to 125V, which is not ideal for a 100V device.


1 Like

I use one of those for my Pre - It’s worked well

Did the custom Allnic pre not hit the spot?
Certainly sounded interesting.

The airlink ones are excellent and their service is very good.

Another thumbs up for airlink

Really useful info here - thanks!

Sadly not heard it yet :slightly_frowning_face:

Custom step-down transformers, designed for audio, should be nice and quiet. But if you were thinking about buying a general purpose one then it would be worth checking to see whether it buzzes/hums electromechanically when it’s working. If you ever get DC on your mains that can make transformer buzz/hum a lot worse.

The other question to ask is about ‘regulation’. This is the variation of the transformer’s output voltage with load. In ‘ordinary’ transformers this can easily be 10%, which means you get 100VAC out when the thing is running at its rated load but 110VAC when it’s off load. If the load presented by your amp varies depending, for example, on the loudness of your music then you will get effective supply voltage variations in time with that. This is already a ‘feature’ that the amp manufacturer is dealing with in his own mains transformer of course. The easiest way to fix it with an external step-down is to buy one that is much bigger than you need. Then it never runs at anywhere near its rated value. But it will be physically large and correspondingly expensive.



Thanks, that’s helpful to know.

I’m going to have a listen to some jap power amps tomorrow that I like the look of. If I took the plunge and bought them then I might also want to try to find the unobtanium matching preamp. If it’s resurrected then the Graaf will do duties until I find one or give up!