DaveP said:Your design is almost identical to the amp on an LA-2A, so if you copy that it will solve your problem. The pot will have to go before it as others have said.
DaveP
BluegrassDan said:Except the La2a is line-level.
It is a trade off between noise and headroom. You current schematic with the transformer connected straight to the first stage tube and a potentiometer after it should have a better noise performance but this in paired with an equal worsening of headroom at lower gains. Because the gain is fixed and it has a fixed maximum output level, as the input increases the headroom decreases. Arguably a better solution is to have two pots, one before and one after the first stage. Every reduction in gain then both reduces output noise AND limits the loss of headroom. This is effectively what happens when you use the input pad.BluegrassDan said:The La2a potentiometer is before the first gain stage. I’d be concerned that attenuating a mic signal before the first gain stage would cause noise problems.
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