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Adjusting a Coleman reg

Posted by andy evans (A) on October 12, 2023 at 02:30:59

In Reply to: RE: Look up the data! posted by xaudiomanx on October 11, 2023 at 11:26:00:

Rod Coleman's regs have

1. A filament resistor that suits the current of the tube
2. A trimmer for fine adjustment

For the V4-8 regs the filament resistor is 0.51R for 46 and 0.6R for 45. So with a 0.6 resistor you would either just about reach 2.5V or you'd max out the trimmer at 2.4V or 2.3V. Won't do any harm for a quick comparison. His V9 latest reg may have more range.

But as Stephen says, the operating points are different, the bases are different plus you'd have to put a resistor between anode and screen grid.

This sounds like tube rolling just for the sake of tube rolling. I'm pretty sure the 45 will sound better so frankly I'd forget the whole thing. That is unless Radu has built 2 sockets into the unit, a ux4 and a ux5. What is it anyway, a line stage? I've used 46 and 47 in line stages and of the two the 47 sounds better to my ears. Cheaper than a 45. But if you already have 45s stick with those.

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