I'm trying to help someone determine if a X250.5 from US has a transformer and board that can change 110V to 220V.
An old thread on this forum addressed this issue, but was incomplete and confusing.
Nelson believed the USA amps made up to 2006 (?) were supplied with multi-use Plitrons. The transformer in question has 6 leads, with 3 soldered in a straight line of 3 holes, and the other 3 soldered similarly.
The other thread described a 110V transformer that had only 3 leads, and the Italian importer said it could not be configured for 220V.
Does six leads mean it can be used for any voltage via a jumper change?
An old thread on this forum addressed this issue, but was incomplete and confusing.
Nelson believed the USA amps made up to 2006 (?) were supplied with multi-use Plitrons. The transformer in question has 6 leads, with 3 soldered in a straight line of 3 holes, and the other 3 soldered similarly.
The other thread described a 110V transformer that had only 3 leads, and the Italian importer said it could not be configured for 220V.
Does six leads mean it can be used for any voltage via a jumper change?
Recently my friend also had a chance to buy used x250.5 from USA and had the same dilemma. The seller even contacted PassLabs and was told that the conversion for that model is not possible. Thinking about it, it seemed to me quite impossible for Plitron to make to different transformers for the same job, so I guessed that new "single primary" versions were just internally bridged same old transformers.
Lucky for me (since my friend bought that amp based on my presumption) it turned out I was right.
In less than an hour, with a little help of multimeter, xacto knife, pliers and soldering unit the US rated X250.5 became EURO.
One can even take out all the taps to have 110,120,220,240V connection possibility. And main fuse should be also changed. (Less important when going to a higher voltage).
I think it's a great news for all buyers interested in used PassLabs amps.
Lucky for me (since my friend bought that amp based on my presumption) it turned out I was right.
In less than an hour, with a little help of multimeter, xacto knife, pliers and soldering unit the US rated X250.5 became EURO.
One can even take out all the taps to have 110,120,220,240V connection possibility. And main fuse should be also changed. (Less important when going to a higher voltage).
I think it's a great news for all buyers interested in used PassLabs amps.
I don't know about that. I just told what happened. Anyway... that was the unit with the Plitron transformer for which was told (by PassLabs) that it couldn't be converted to 220V because it is single primary. Procedure included taking off protective band around transformer and cutting through isolation strip. Primaries were briged inside - beneath all that isolation and crimped to the color coded output wires (just three of them). So, indeed, it wasn't supposed to be converted to 220V, but it could be done.
I really doubt that Plitron makes special new transformer for PassLabs 220-240 models, because all their amp PS transformers have multiple primaries and transformer manufacturers prefere to use multiple thinner wires to single fat wire. It's so much easier for them to crimp those taps to output wires inside and there is no real reason to make true single primary. Except if your intention is to prevent transcontinental used PassLabs amp sale.
I really doubt that Plitron makes special new transformer for PassLabs 220-240 models, because all their amp PS transformers have multiple primaries and transformer manufacturers prefere to use multiple thinner wires to single fat wire. It's so much easier for them to crimp those taps to output wires inside and there is no real reason to make true single primary. Except if your intention is to prevent transcontinental used PassLabs amp sale.
When I read the January post, I asked Plitron whether that form of
construction was correct in the model we were purchasing. They
informed me that it is not, specifically that the transformers in
question have a single primary, not dual primaries with hidden
connections.
I don't recommend that anyone assume that they can successfully
perform that surgery.
construction was correct in the model we were purchasing. They
informed me that it is not, specifically that the transformers in
question have a single primary, not dual primaries with hidden
connections.
I don't recommend that anyone assume that they can successfully
perform that surgery.
So, that was some "in between" version? Because; in the first version transformers had multiple tapped dual primaries (110, 115...240V), the version "in between" had same dual primaries but tapped as single with connections hidden beneath isolation tape. And the third version is pure single primary?
Correct?
Correct?
I don't know how there would be such a beast as you describe. There
were transformers that could be tapped for 100,120,200,220, and 240.
The current transformers have taps for 6 voltages, but the range does
not extend from the 100's to the 200's. It requires a separate transformer.
There was no "transitional" transformer in our records.
were transformers that could be tapped for 100,120,200,220, and 240.
The current transformers have taps for 6 voltages, but the range does
not extend from the 100's to the 200's. It requires a separate transformer.
There was no "transitional" transformer in our records.
Well, either what you see in the picture was some nonexisting plitron transformer or maybe they didn't give you correct information.
Whole plitrons production is based on multiple primaries transformers, and I bet they wound their transformer primaries all the same, and then according to demand of production tapping them and wound secondaries.
For large power toroids one needs large diameter wire to get single 110V primary and it's hard to wind it and get proper tension with it, so manufacturers usually use parallel thinner wires.
Whole plitrons production is based on multiple primaries transformers, and I bet they wound their transformer primaries all the same, and then according to demand of production tapping them and wound secondaries.
For large power toroids one needs large diameter wire to get single 110V primary and it's hard to wind it and get proper tension with it, so manufacturers usually use parallel thinner wires.
No, the transformer was Ei-Nis ; of course the transformer was original. The amplifier was bought at audiogon and the owner asked Pass Labs if the transformer could be switched to EU voltage (he supplied S/N). The answer was NO. Anyway, the amp was bought with the risk of eventual new transformer buy, but it wasn't necessary
It wasn't easily converted - it had only primary taps - you can see cut off wires in the picture.
It is 250.5 amplifier.
If you don't believe me, how about cutting through isolation of one of your transformers... than you would be sure and you could call Plitron and have refund or call me a liar. 
; of course the transformer was original. The amplifier was bought at audiogon and the owner asked Pass Labs if the transformer could be switched to EU voltage (he supplied S/N). The answer was NO. Anyway, the amp was bought with the risk of eventual new transformer buy, but it wasn't necessary It wasn't easily converted - it had only primary taps - you can see cut off wires in the picture.
It is 250.5 amplifier.
If you don't believe me, how about cutting through isolation of one of your transformers... than you would be sure and you could call Plitron and have refund
or call me a liar.
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