Phonoland

On my Wurlitzer 546 amp, I had a side of one of the power amps dead. I found one of the output power transistors was gone, and I read that you needed matched pairs. I ordered a matched pair from a seller on this forum. While waiting for the transistors I recapped the amp.
When I got the transistors put her all together tried and found the PA where I replaced the transistors was crackling. I discovered it was the new transistors. So I found another set ordered them, same thing. I did not know if I was overdriving the transistors or the speakers. I changed the 1.8 ohm resistor on the input of the 2 pa transistors to a 5 ohm resistor, noise was gone, a little lower output level but the heat sink for the transistors was just warm. Changed the five ohm to 2.7 still good and housing was still slightly warm. Question I have is it normal to have to change the base bias of the power transistors when you change the transistor. These are not Wurlitzer parts but a replacement part.

David

Your questions are impossible to answer due to the lack of details concerning this amp.
Other problems may persist, such as driver circuit issues, voltage imbalances, etc., and certainly cannot be diagnosed over the internet.

Third set of transistors cured the problem. Both pa functionally properly with no noise and equal gain. The pa is now back the way
it was. Thanks to Jukebox Revival for suggesting and selling me different substitute transistors. I was thinking of changing to silicon per
an article Jay had written.