Biasing the ATM3's are very simple :
Run the amp to warm them up.
Turn the volume pot on the ATM3's to minimum.
Remove the front centre panel that has the Airtight logo on it.
You then elect each tube using the tube bias selector switch.
When you select each tube you then adjust the bias to the "bubble" range printed on the bias meter.
It is very straightforward.
Run the amp to warm them up.
Turn the volume pot on the ATM3's to minimum.
Remove the front centre panel that has the Airtight logo on it.
You then elect each tube using the tube bias selector switch.
When you select each tube you then adjust the bias to the "bubble" range printed on the bias meter.
It is very straightforward.