Converting input voltage from 100/110/120v to 240v

[Tangerine]

Hello,

I’m wondering if it’s conceivable to alter the power supply of a piece of gear to enable a different input voltage to that originally designed?

Has anyone done such a thing?
Are there “mod kits” or instructions out there that would enable such a change to be done?

All discussions accepted.

Thanks

 

[rcs16]

Not so easy to do if you want it self contained in the original housing. In many cases it’s the transformer that needs changing. Some use external step up/down transformers but that is imo messy but it is an easy solution and can be expensive.

 

[whoaru99]

Some gear has switchable input voltage. Some by an external selector/switch, some by changing the connections on an internal terminal strip or internal jumpers. Have to check the specific item.

 

[gadget73]

^^ basically this. If you don't have a multi-voltage transformer, there really isn't a practical way of doing this. You're stuck with a step-down transformer or switching the trafo to a multi-voltage unit.

 

[noahBH]

A step-up or step-down transformer can be had from Amazon for less than $100. I ran a 220 volt Pioneer receiver this way. Its not ideal, but its not a huge pain.

 

[Tangerine]

^^ basically this. If you don't have a multi-voltage transformer, there really isn't a practical way of doing this. You're stuck with a step-down transformer or switching the trafo to a multi-voltage unit.

My intention was to change out power supply components to meet the input mains voltage.
The simple way would be to use a cct diagram from a 240v variant and replace components as needed. The trick would be the transformer of course depending in the input/output windings ratio and it’s power handling.
You could assume that they use the same transformer for all voltage variants to save costs and then it’s a matter of using the correct tap.

 

[Tangerine]

A step-up or step-down transformer can be had from Amazon for less than $100. I ran a 220 volt Pioneer receiver this way. Its not ideal, but its not a huge pain.

You are spot on, I do have a few step down trannys that the local US embassy were getting rid of, but they are quite clunky, still they do allow me to use US sourced gear.

 

[whoaru99]

Except the assumption may not be correct. Speaking from experience with Yamaha, some have 120V only transformers, some have 240V only, some have multiple choice.

Have to look at the specifics of what you have. Service manual for the specific model may show what variants they made re. different mains voltages.

 

[redk9258]

You could assume that they use the same transformer for all voltage variants to save costs and then it’s a matter of using the correct tap.

I would highly doubt that. All of my stuff that I've been into does NOT have extra taps to change voltage. The service manuals list different transformers for different areas / voltages.

 

[john stumpf]

if its a dedicated us model using 120 vac there are NO unused primary taps in pioneer receivers ive worked on. the easiest route is buy an automatic transformer. they sell meiji's here and they work very well and keep the input voltage stable as well. other than that the only other thing you can do is get the "world market'' transformer the back panel too with the selector switch would be a nice touch,but you wouldnt necessarily have to. its also fair to note that the master switches are double pole on the multi voltage sets as some locales in the world use two 110/115/120v phases loaded to each other to get 240 or 230 in australia you guys use 240 to neutral and its also fair to note you are at 50 hz. im not sure how pioneer factored the frequency/ reactance variations into this in their world market designs. if it were i. and i was in a 240/50hz scenario, i would get an auto transformer and play with the voltage adjustment thats internal on the auto transformer internal circuit board. i would start by setting the output a bit low and adjust as necessary to make sure the secondary outputs in the RECEIVER were in line with the specs from pioneer and i wasnt overheating the transformer. ive never been in that scenario, but on the face of it this seems reasonable to me

 

[jojo0416]

I have a few 100V equipment and looking for a stepdown from 120V to 100V is difficult and expensive. I am currently using a 2KW variac, costed me $100.

 

[Jett_Rus]

Hey! Any transformers for 220V audio applications can be ordered. I bought two toroidal transformers for my . The main thing is that they fit the size of the case.
I had to install the transformers vertically.
My amp is currently under restoration...

 

[AudioAvarice]

I use stepdown transformers for my 100v Japanese Kit here in the UK, I can recomend the Nissyo made ones, yeah their bulky, but well made, the cream faced ones in the turquoise cases have the best 'vintage' aesthetic imo, but can be expensive. Just make sure to use one thats rated at least double the wattage of the unit.

I brought a Japanese made clone of a Nissyo from ebay a few years ago, visually identicle, but made by 'Fujikawa electric co.ltd' I was a little reluctant because in caps at the top of the front panel, it says 'STEP-DOWN TRANSFOMER' but it was a bargain for one rated at 1000VA(watts).