Transformer questions

[diode breath]

I found a couple old transformers lyin' around, bought in early '81 when I lived in Houston. The idea of a Boogie clone was a big thing for me then, but I have LONG since gotten over the idea of a 100-watt combo.

The PT has a Fender P/N (022756, dated 606-107) and the OT has a number with which I'm not familiar (T100-152019, dated 606-923).

Anybody familiar with the OT number? Any ideas for using these units without causing tinnitus or bleeding ears? They're too big for using with a 20-watt amp.

Suggestions? Ideas?

Thanks,
diode Breath

[Enzo]

22756 is the PT for the Fender Twin Reverb and others.

I don't know the other, but the T100 looks suspiciously like it is for 100 watt, but could be a coincidence.

[diode breath]

Thanks, Enzo!

Hey!

I appreciate your response, Enzo. I bought both transformers from a Fender Authorized Service Center in Houston in '81. As I said in the original post, I was going to build a Mark I Boogie clone, but I no longer feel a burning desire to have my ears bleed. I'm more into <25-watters, thanks.

I knew the PT was a Fender, but didn't check unitl just recently on the OT. Isn't 606 the EIA code for Triad?


I hadn't ever checked the DC resistance of the OT until today. It has the usual red-brown-blue secondaries, but the primary is green-yellow-black. Resistances are as follows:

Primary: Red to brown ~36 ohms
Red to blue ~36 ohns

Secondary: Green to black ~0.6 ohms
Yellow to black ~0.6 ohms
Green to yellow ~0.6 ohms

I'm guessing that it's a 4/8 ohm OT, but I would've thought that the primary resistance would be higher. It it's for a 100-watt amp, that'd pretty much gurantee 4-6L6 or 4-EL34 tubes, which'd require about 4K ohms primary impedance, correct? If so, I would have expected the DC resistance to be more than 36 ohms.

Niether transformer has been used -- ever. I had a buddy bend up a chassis something like a Princeton, but the daffy barstid used stainless steel instead of mild. Made it a stone bitch to cut holes for the transformers.

Thanks again, man!
diode Breath

[Enzo]

Transformers have no impedance of their own, they "Transform" impedances. The impedance at the tubes is a reflection of the impedance of the speaker load. Transformers work on turns ratios. The resistance is just the resistance of the wire of the winding..If it measures 50 ohms, and I rewind it with the same number of turns but use much heavier wire, then it might measure 15 ohms, but the impedances remain the same, because the turns ratio and the load determine what the tubes see.

In other words, that 8/4k ohm transformer only shows the tubes 4k when an 8 ohm load is on the secondary. That is why when we pull two of the tubes from a 100 watt amp to make it 50 watts, we also have to move the impedance tap for the speaker for the tubes to see the right impedance.

[Tim C.]

606 stands for Schumacher Transformer Company.

TC