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Home Theater => Audio => Amplifier => Topic started by: dench on Nov 11, 2014 at 04:18 AM

Title: Converting 120V tube amp to 240V compatible
Post by: dench on Nov 11, 2014 at 04:18 AM
Hello PDVDers,

How easy is it to convert 120V into 240V? What parts would be replaced? Who are your recommended technicians in Manila who could do this (Rene Rivo?) and any idea how much it would cost?

I believe converting the amp voltage would not degrade the amp's performance and reliability...

Maraming salamat to all who will reply!

Title: Re: Converting 120V tube amp to 240V compatible
Post by: qguy on Nov 11, 2014 at 05:38 AM
Replacing the PRIMARY WINDING in the power transformer should not affect performance if done correctly.

If your wall outlet is 220v, you might loose a little power in output, well that what the designer of my subwoofer said, when I said that my wall outlet is 220v and the subs plate amp is switched to 240v.

Recommended techs.

Mang ROD
AT&S
Title: Re: Converting 120V tube amp to 240V compatible
Post by: tony on Nov 11, 2014 at 07:06 AM
converting to 240 volts is very easy if your power traffo came in with dual primary windings of 120 volt each....
this is the VTL Theta 6550 pp amp monoblocks i converted...it takes longer to dismantle the covers...

this is before converting...
(http://i5.photobucket.com/albums/y155/leoman53/Facebook/Theta%20MonoblocksVTL%20preamp/843065_526182827403356_1856848588_o.jpg) (http://s5.photobucket.com/user/leoman53/media/Facebook/Theta%20MonoblocksVTL%20preamp/843065_526182827403356_1856848588_o.jpg.html)

after converting...
(http://i5.photobucket.com/albums/y155/leoman53/Facebook/Theta%20MonoblocksVTL%20preamp/778644_526183044070001_464854176_o.jpg) (http://s5.photobucket.com/user/leoman53/media/Facebook/Theta%20MonoblocksVTL%20preamp/778644_526183044070001_464854176_o.jpg.html)

if your amp traffo has just one primary winding of 120 volts, it gets more complicated as you will need to get it extracted out of the amp and rewinded for 240 volt primary...
Title: Converting 120V tube amp to 240V compatible
Post by: dench on Nov 11, 2014 at 08:02 AM
Thanks qguy and tony!
Title: Converting 120V tube amp to 240V compatible
Post by: dench on Nov 11, 2014 at 08:02 AM
I might be wrong Philippines is 220v right? Not 240v
Title: Re: Converting 120V tube amp to 240V compatible
Post by: tony on Nov 11, 2014 at 08:50 AM
I might be wrong Philippines is 220v right? Not 240v

240 is better...but i design my traffos to work on 230 volts, no biggie here...
where i am, voltage ranges from 218 to 235 volts, i not worried a bit... ;)
Title: Re: Converting 120V tube amp to 240V compatible
Post by: markcrenz on Nov 11, 2014 at 10:59 AM
In case you will need to have it rewound, find the ones recommended by qguy. Lesser techs may rewind it for cheap, but in the end you might get higher secondary voltages, less current capability and/or vibrations from poor rewinding.

I might be wrong Philippines is 220v right? Not 240v
220V standard, pero sa area ko very stiff at 240v ang nominal voltage and I kind of like it. We're very close to the Meralco transformer btw.
Title: Re: Converting 120V tube amp to 240V compatible
Post by: tony on Nov 11, 2014 at 11:17 AM
In case you will need to have it rewound, find the ones recommended by qguy. Lesser techs may rewind it for cheap, but in the end you might get higher secondary voltages, less current capability and/or vibrations from poor rewinding.
220V standard, pero sa area ko very stiff at 240v ang nominal voltage and I kind of like it. We're very close to the Meralco transformer btw.

reminds me of my stay in nueva ecija, my house sa next to a pole with the distribution transformer...
never had to worry a bit...240 volts day in and day out...
Title: Converting 120V tube amp to 240V compatible
Post by: dench on Nov 19, 2014 at 12:43 AM
Hi guys,

Would you have an idea on the cost of conversion? Parts and labor?

What if we just use a stepdown AVR and plug the amp there?

Title: Re: Converting 120V tube amp to 240V compatible
Post by: tony on Nov 19, 2014 at 07:12 AM
Hi guys,

Would you have an idea on the cost of conversion? Parts and labor?

What if we just use a stepdown AVR and plug the amp there?



if your amp is for keeps and not planning on selling later,
then conversion to 220 is the way to go...
otherwise, just use the step-down traffo....
Title: Converting 120V tube amp to 240V compatible
Post by: dench on Nov 19, 2014 at 08:15 AM
Thanks tony!
Title: Re: Converting 120V tube amp to 240V compatible
Post by: JojoD818 on Nov 19, 2014 at 10:25 AM
Hello PDVDers,

How easy is it to convert 120V into 240V? What parts would be replaced? Who are your recommended technicians in Manila who could do this (Rene Rivo?) and any idea how much it would cost?

I believe converting the amp voltage would not degrade the amp's performance and reliability...

Maraming salamat to all who will reply!




It's really not as easy as others may have put it. Madali lang sabihin pero mahirap gawin.

Anyway, the new primary may not fit the original bobbin if you keep the original wire gauge. Making it smaller in gauge to accommodate more number of turns will affect the available power from the transformer so it's not a good way to go, unless the bobbin still has plenty of space.

If that's a keeper, ask Edrel to make you a new one, I guarantee you it will be a wise decision.

If you just want to use a step down like tony said, replace the plug of your tube amp with a round prong so it cannot be accidentally plugged into the 220V mains.

Title: Re: Converting 120V tube amp to 240V compatible
Post by: AudioAmplified on Nov 19, 2014 at 11:51 AM
AVR or transformer should do the job without additional cost.  Furthermore, keep in mind that transformers are in a way the heart of your amp so as much as possible it would be better to just keep the original unless you have problems with the transformers.

What i do for my 110v appliances is I tape it on the socket to prevent people from accidentally plugging onto a 220V outlet.  :)  cheers
Title: Re: Converting 120V tube amp to 240V compatible
Post by: tony on Nov 19, 2014 at 12:05 PM
why not post the underside of your amp showing the trannie, then we will have a better idea....
vintage american gears will have those dual 110v primaries, maybe 80% of the time....
Title: Re: Converting 120V tube amp to 240V compatible
Post by: Gino on Nov 20, 2014 at 12:57 AM
Back when I was using the 110v Fisher I used a Panther 500w step down transformer. It sounded great and gave me no trouble for all those years.