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Solid State Amplifiers => Amplifier Discussion => Topic started by: RDV on May 16, 2006, 07:34:53 AM

Title: Talema Transformer Wiring Mystery
Post by: RDV on May 16, 2006, 07:34:53 AM
I just picked a 20v + 20v @ 5amps(200VA) Talema transformer. It's supposed to be a single primary and dual secondary. I guess it's a few years old NOS so I can't find any info on any website.

There are two double insulated(orange covered by yellow) stranded wires, and there are four solid wires(black, white, red, & green).

Would anyone know the deal with these? Would the two stranded wires be the primary? That's the only thing that makes sense if this is a single primary/dual secondary transformer.

What's strange to me is the lighter(though double insulated) wires being the line voltage & the heavier being the 20v.

I also searched the net for the word Talema and the only diagram I saw was not like this transformer.

I got continuity between the two yellow wires, between the black & white, and between the red & green.

I measured the resistance between the three pairs and got 3.3 ohms between the two yellow wires.

.8 ohms between the other two pairs.

Does this mean the two yellow wires are the primary? I got a response at DIYaudio saying that the larger resistance would be the primary, but I'd like an R.G. opinion on that one.

Please advise.

RDV
Title: Re: Talema Transformer Wiring Mystery
Post by: joecool85 on May 16, 2006, 07:41:52 AM
The primary wires could very well be a smaller gauge, think about it.  It is a 200VA transformer, wire gauging is mostly to compensate for amps.  The more amps, the bigger the wire.  The AC is 110-120v, lets use 110 for the math.  200VA/110V = 1.8 amps going through the primaries.  Now the secondaries.  200VA/40V = 5 amps.  It makes sense when you think about it.  I would say the two small heavily insulated wires are most definetly primaries.

**edit**
I should note that its really probably half that for the secondaries since there are two sets.  So 2.5, but thats still more than the 1.8 primaries.
Title: Re: Talema Transformer Wiring Mystery
Post by: RDV on May 16, 2006, 08:24:17 AM
I asked the guy a bought it off of and he told me the black & white were the primaries but I don't think he ever hooked one up. He just got continuity between them and assumed. He sold about 4 of them and if others follow his advice they're going to burn up their trannys. No way would the secondaries be two different kinds of wire. I bought this one for the LM1875 kit when it comes along.

RDV

(http://fatboy.ssguitar.com/index.php?dir=schems/&file=d6_1.jpg)
Title: Re: Talema Transformer Wiring Mystery
Post by: joecool85 on May 16, 2006, 08:38:03 AM
I can't tell in the pic, but does that mean my assumptions were right or wrong?

**edit**
Nevermind, I figured it out, I was right.   :P
Title: Re: Talema Transformer Wiring Mystery
Post by: RDV on May 16, 2006, 09:11:50 AM
I think everybody's right but the f**ker that sold me the toroid. Of course the smoke test will be the final judge. I wanna hear from dear Uncle R.G. before I try that though.

RDV
Title: Re: Talema Transformer Wiring Mystery
Post by: joecool85 on May 16, 2006, 09:24:24 AM
Does he still check this board?
Title: Re: Talema Transformer Wiring Mystery
Post by: RDV on May 16, 2006, 10:10:31 AM
Does he still check this board?
Every now and then I think, but I'm hedging my bets, I've posted this EVERYWHERE. I value everyone's input. I've learned some key stuff like the DC resistance being higher on the primary because of there being more windings there. That's huge.

RDV
Title: Re: Talema Transformer Wiring Mystery
Post by: RDV on May 16, 2006, 10:19:32 AM
The ebayer emailed with a correction, he now says the yellow wires are the primary. At least he owned up.

RDV
Title: Re: Talema Transformer Wiring Mystery
Post by: joecool85 on May 16, 2006, 10:30:30 AM
Cool, so I was right.

Make sure to post when you get the thing working and stuff.