[TechWiz]

About 9 months ago I built my first 566, and I loved it so much that I got myself a second one not that long ago. Today I wanted to use the as a stereo pair to record Room Mics when I realized that the new one has a significant amount of less gain then my first one. It still sounds fine, the gain level switch works as it should, it behaves completely normal except for thet fact that it has way less headroom then my first module.

Does anybody have an Idea what could cause this loss of gain?

Thanks in advance!

[JPK]

the new one has a significant amount of less gain then my first one.

Try swapping the tubes between the units, in case one tube would be defective.

With the drive pot to max and level pot to min, send a strong sine signal (like 0.5VAC) to the input then measure the AC levels you get on TP1 for both units. Are they different?
Next, with both drive and level pots to max, lower the input signal in order to get no distortion on the output and measure the AC levels on TP3 for both units. Are they different?
Next, measure the AC levels on TP4 for both units. Are they different?