rogers cadet

[Paul Rayson]

I have replaced the OPT's on my rogers cadet 3, they have a output of 4 and 8 ohms. the feed back come's from a 15 ohm winding.Can somebody help regarding, possibly a resistor in series to balance things out

 

[Alan4411]

Without test gear you will have to use trial and error.
You will need to reduce the value of the feedback resistor (6.8K - R29 on the 'all in one' model, R15 on the 2 unit model.) slightly. Try 5.6k or 4.7k or maybe use a 10k pot in place of the 6.8k and adjust it down?

 

[Steve Morley]

I've seen two versions of the Cadet schematic, the single box and the two-box version. Both use the same resistor, 6.8K, but the FB capacitor is 100pF on one version and 390pF on the other.
Just a wild-*** guess, but try changing the resistor over to about 4.7K and the cap to about 1.5x its current value. This is connecting it the 8 ohm tap on your new trannie. But if the amp is working fine with the existing FB values just leave it.

A 15K resistor in parallel with the existing 6.8K results in close as damnit to 4.7K. Easy to try and minimally invasive. Maybe try this first with the existing FB cap and call it a day.

Steve

 

[Paul Rayson]

Thank you everybody for the feedback and guidance, I will try all advice to see which works best