Transformer Question

[soggybag]

I'm building a Psychtar (http://www.geocities.com/tpe123/folkurban/fuzz/psychtar.gif) and a Titan Boost (http://www.hollis.co.uk/john/titan_boost.jpg). Both use transformers. How do I figure the orientation of the the transformer? The transformers I have are marked P on one side for Primary how does this relate to the schematic?

[soggybag]

bump

[jmusser]

The Psychtar transformer ( and most of the octaves that have transformers, use the "P" on the output. This is totally contrary to what most people are used to, but it turns a step down to step up, since were talking very small voltages and currents. I believe the boost goes from primary to secondary but I'll have to check it on mine to be sure when I get home. As far as I know, that transformer is a Maplin only item. If you make the Titan Boost, I can send you a drawing to show you how to switch the octave in and out, it's just a couple more components (diode bridge) and it really suits the boost well. Very Warm and not over powering. A lot of these circuits (I believe the Bronx Cheer is one) only use half the transformer as an inductor, and the other winding of the transformers left out of the circuit.

[soggybag]

Thanks for the reply. Any information you care to send on the Titan boost would be very helpful. I have already built most of it. I used the GEO layout, which lists a Mouser part number 42TM006. This transformer is 1K to 20K which is different from the maplin part, but it's all I can get here in the states.

Here's a link to the data sheet http://www.mouser.com/catalog/specsheets/164267.pdf.

In the data sheet it shows three leads on a side labeled 123 and 456. It shows 1 and 2 as the primary and 4 and 5 as the secondary? I would have thought the center leads, 2 and 5, to be the center taps?

[idiot savant]

Here's a link to the data sheet http://www.mouser.com/catalog/specsheets/164267.pdf.

In the data sheet it shows three leads on a side labeled 123 and 456. It shows 1 and 2 as the primary and 4 and 5 as the secondary? I would have thought the center leads, 2 and 5, to be the center taps?

the middle leads on both sides are center taps, just as you suspected. you use the outside leads on both sides. i cant say for the titan boost, but on the psychtar i have been told it doesn't matter what side you point the primary towards, because it is a 10K:10K transformer with a 1 to 1 turn ratio. when i used have used transformers in my builds (Gus' SOU, and Tim's Jawari) i just left the extra unused center tap not connected.

[soggybag]

What I meant was it looks like the data sheet is telling me to use leads 1 an 2 as the primary and 4 and 5 as the secondary? There is a black dot next to these leads on a diagram in the data sheet. I'm not sure what they are saying?

Is there a way to test it with a multimeter?

[jmusser]

I'm looking at the Mouser book right now, and it looks like those "dots" you speak of, are orientation marks. If you have these dots oriented towards the top of the PC board, then that means, that you'll have the primary on your left, and the secondary on your right. That way, if your transformer is not stamped woth a "P" on the side of it where the winding insulation is, then you'll have a way to identify it's orientation. You will be able to check from that dot, to the leg that's on the same side at the bottom for resistance. The transformer data sheet will tell you what resistance you're supposed to have for that winding. Also, I have never seen a transformer, that didn't have the primary and secondary pins separated on both sides by the core. Hope that's what you needed. I'm glad that RG has found a non Maplin transformer for this build over on the GEO site.

[soggybag]

Thanks for the reply I think this is the information I need to finish this up.

You must have ingenius method for switching the octave in and out. In the RG layout he admits that the problem vexed him to the point where he left it out, and he's pretty sharp!

I'd be interested in seeing your method.