Crossy :-) Using 110v stepdown transformer for a Japan import 100v AC guitar amplifier

[Kenny202]

Got a 100vac amp I got from Japan. Very easy to buy a 110v step down transformer but not so easy to find 100vac. What do you think Crossy? Would 110v be ok / not damage the electronics? Our power supply here is so variable anyway. The amp is 60w and the power supply is 100w so that's covered. Appreciate the help ????

[Crossy]

10% over-voltage will likely be fine, but I'd try to find a pukka 100V transformer. IIRC the Japanese department store in Bangkok used to sell them (is it still even there??).

 

BUT

 

If it specifies 100V 60Hz rather than 50/60Hz I'd be wary of running it on 110V 50Hz.

[Kenny202]

Thanks Crossy, it does say 50/60hz. I will give it a whirl. Pretty sure I have used them before. It is nearly impossible to find 100vac step downs here at any price and the rare few are too pricey or actually questionable if actually 100v and not 110v

[lopburi3]

42 minutes ago, Kenny202 said:

Thanks Crossy, it does say 50/60hz. I will give it a whirl. Pretty sure I have used them before. It is nearly impossible to find 100vac step downs here at any price and the rare few are too pricey or actually questionable if actually 100v and not 110v

Japan uses both 50hz and 60hz (depending on where in the country) so anything for domestic use should be able to cope.  

[sometimewoodworker]

1 hour ago, lopburi3 said:

Japan uses both 50hz and 60hz (depending on where in the country) so anything for domestic use should be able to cope.  

Having lived in japan for almost 30 years that statement is wishful thinking and from personal knowledge is not correct. there are many, though not the majority of, items that are region specific so you definitely need to check the information on the items to be sure.

[lopburi3]

33 minutes ago, sometimewoodworker said:

Having lived in japan for almost 30 years that statement is wishful thinking and from personal knowledge is not correct. there are many, though not the majority of, items that are region specific so you definitely need to check the information on the items to be sure.

I only lived there about a 1/10th of that time but found it true for things I bought - but as it is cheaper to go 60hz (as most exported to US were) expect may be true.  My time was early 60's and before export market was at its peak.

[Kenny202]

I actually picked a little 100w Hitachi 220/100v transformer up off Lazada 300 baht. Damn hard to find with Lazada's crappy search but got there in the end. I did talk to my guitar amp technician....he did actually say 110 volt would be no problem at all and that guy knows his shet ????  

[murphybridget]

On 10/7/2023 at 12:20 AM, Crossy said:

10% over-voltage will likely be fine, but I'd try to find a pukka 100V transformer. IIRC the Japanese department store in Bangkok used to sell them (is it still even there??).

 

BUT

 

If it specifies 100V 60Hz rather than 50/60Hz I'd be wary of running it on 110V 50Hz.

Hey Crossy, a 110v step down transformer should generally be fine for your 100vac amp, especially since power supplies can be quite variable. 

[Crossy]

1 minute ago, murphybridget said:

Hey Crossy, a 110v step down transformer should generally be fine for your 100vac amp, especially since power supplies can be quite variable. 

 

The problem is, if it's a dedicated 60Hz transformer then it may overheat even on 100V 50Hz, running it on 110V 50Hz would make that issue worse.

 

I agree that it would "probably" be OK, but in my business "probably" isn't good enough.

[Kenny202]

You're a bit late to the party Crossy lol? I have at least 6 Japanese electronic things including guitar amps, effects units etc all Japanese 100v and the 110v 50hz transformers work fine. Usually the actual 100v transformers are hard to find and expensive but seem to be more readily available now (per my post above), particularly the smaller adapter packs.

[bluejets]

12 hours ago, Crossy said:

I agree that it would "probably" be OK, but in my business "probably" isn't good enough.

Me too....transformers as a whole are fairly robust and will withstand spec way out side of recommended without failure.

The associated electronics should be good for a fair range outside of spec also.

[murphybridget]

On 5/16/2024 at 4:23 AM, Kenny202 said:

You're a bit late to the party Crossy lol? I have at least 6 Japanese electronic things including guitar amps, effects units etc all Japanese 100v and the 110v 50hz transformers work fine. Usually the actual 100v transformers are hard to find and expensive but seem to be more readily available now (per my post above), particularly the smaller adapter packs.

That's good to hear.

[lopburi3]

On 5/16/2024 at 6:23 PM, Kenny202 said:

You're a bit late to the party Crossy lol? I have at least 6 Japanese electronic things including guitar amps, effects units etc all Japanese 100v and the 110v 50hz transformers work fine. Usually the actual 100v transformers are hard to find and expensive but seem to be more readily available now (per my post above), particularly the smaller adapter packs.

Japan uses both 50Hz and 60Hx supplies so transformers are built to handle the increased requirements of 50Hz.  Stepdown transformers as often found in mass market USA will be built for 60Hz operation only to save a few cents in production.  In turn they may overheat.

Quote

Operating a transformer at 50 Hz generates 20% more flux lines than at 60 Hz. As the number of flux lines approaches the magnetic material's limit, the heat in both the magnetic core and the internal coil wires increases, and under certain circumstances, unpredictably so.

https://www.controleng.com/articles/why-do-50-hz-transformers-cost-more-than-60-hz-transformers/#:~:text=Operating a transformer at 50,under certain circumstances%2C unpredictably so.

Edited May 20 by lopburi3

[carlyai]

You could probably find a variable (manually adjustable) power supply in the Yarrawat region (near China town in Bangkok), as long as the current supply is enough.

Be Warned: once you start exploring this area you won't want to stop. 🙂

 

[lopburi3]

2 hours ago, carlyai said:

You could probably find a variable (manually adjustable) power supply in the Yarrawat region (near China town in Bangkok), as long as the current supply is enough.

Be Warned: once you start exploring this area you won't want to stop. 🙂

 

Nor will the wife - diamonds among the diodes.