Rewiring a toroidal transformer from 110v to 220v

[jsilvela]

Wondering if someone could give me a hand reconverting a US mains amp to EU mains.
Many years ago, when I lived in Seattle, I bought a CI Audio D100 monoblock to drive a center channel.
Really was just an excuse to get something with the UcD modules...

Before buying I inquired about converting the unit from 110v to 220v, as i thought, rightly, I might move to the EU.
Dusty Vawter emailed me that it was relatively straightforward:

AC input voltage is set by two solder-in jumpers,

At the moment I'm running the amp connected to a voltage transformer.
But I'm curious if anyone knows which jumpers to re-solder on a large toroidal transformer?

Thanks

 

[fpitas]

Probably PC board jumpers? A picture inside the unit might help.

 

[jsilvela]

 

[fpitas]

Looks like the jumpers right there

 

[jsilvela]

Looks like the jumpers right there

Yep!!!
I read 240v in the perpendicular direction.
Should the wires be un-soldered? Re-soldered across?

 

[fpitas]

Yep!!!
I read 240v in the perpendicular direction.
Should the wires be un-soldered? Re-soldered across?

I assume, yes. Remove them both and place one jumper where it says 240V.

 

[jsilvela]

I assume, yes. Remove them both and place one jumper where it says 240V.

Thanks. I don't have the soldering kit on me right now, so tomorrow.
Saw a RS801 rectifier next to those jumpers. Going to see if I can gather more reassurance before going for it.
Thanks!

 

[fpitas]

Thanks. I don't have the soldering kit on me right now, so tomorrow.
Saw a RS801 rectifier next to those jumpers. Going to see if I can gather more reassurance before going for it.
Thanks!

De nada

 

[simbloke]

I would want to check the output of the power supply section without anything else connected, just to be sure!

 

[jsilvela]

I would want to check the output of the power supply section without anything else connected, just to be sure!

agree, but, would need to disassemble the unit to even trace the circuits properly and find where to put my volt-meter.
I am even more scared of not being able to put it back together after

 

[Suffolkhifinut]

agree, but, would need to disassemble the unit to even trace the circuits properly and find where to put my volt-meter.
I am even more scared of not being able to put it back together after

If I was you best to continue using the transformer. Check the transformer’s power rating to ensure it’s big enough to supply your amplifier needs. Be careful when you do living in Libya had to use transformers on some equipment many of them, usually made in Italy had power rating far beyond what was true.

 

[jsilvela]

If I was you best to continue using the transformer. Check the transformer’s power rating to ensure it’s big enough to supply your amplifier needs. Be careful when you do living in Libya had to use transformers on some equipment many of them, usually made in Italy had power rating far beyond what was true.

yeah. I started playing with my solder kit, and realized it needed to go to a much higher temperature than I had hoped.
Better leave good enough alone! The transformer is out of sight and powerful enough.
Thanks!

 

[Zek]

would need to disassemble the unit to even trace the circuits properly

Can you get a service manual to see exactly how the transformer is connected to the PCB?

 

[jsilvela]

Can you get a service manual to see exactly how the transformer is connected to the PCB?

Unfortunately, CIAudio went out of business. It was small-scale, and the documentation was just a page.
I have sent them email asking about the re-wiring. The website says they're still open for support.
Anyway, sent the email two weeks ago, and not holding my breath.

 

[fpitas]

You may know, but the point of the 240V jumper is to put the primary windings in series connection, instead of in parallel for 120V.

 

[jsilvela]

You may know, but the point of the 240V jumper is to put the primary windings in series connection, instead of in parallel for 120V.

No, I did not know! So this is fairly standard?
I started applying my solder kit to the board, and realized it was going to take longer/hotter than I was hoping (haven't soldered in ages).
Got spooked and was unsure I was doing the right thing anyway...

That 240v jumper seems to make good sense.

 

[fpitas]

No, I did not know! So this is fairly standard?
I started applying my solder kit to the board, and realized it was going to take longer/hotter than I was hoping (haven't soldered in ages).
Got spooked and was unsure I was doing the right thing anyway...

That 240v jumper seems to make good sense.

Bog standard, as the English say. Most power transformers these days have two primary windings.

 

[jsilvela]

Bog standard, as the English say. Most power transformers these days have two primary windings.

Well, I did it. Persisted with the heat until the jumpers dislodged, and connected the 240v across.
Working fine, and I can get rid of the bulky transformer.
Thanks!