I'm rebuilding the input board of a Stasis 3 (the 125 wpc version of the Stasis 2).
The schematic shows two 6571 NPN transistors with their collectors attached to the emitters of two A42 NPN transistors. From what I've read, some call this a 'double Darlington pair' and to avoid DC offset, matching the hFE is a good practice.
I found the A42 at Mouser. But the 6571 was out of stock. The NTE website says NTE123AP is a cross-reference equivalent.
I bought extras of both. I found two A42 that are roughly the same hFE (95-105) but the newer NTE123AP are much higher (173-190).
Question: Do the A42 transistors need to match the hFE of the NTE123AP?
The schematic shows two 6571 NPN transistors with their collectors attached to the emitters of two A42 NPN transistors. From what I've read, some call this a 'double Darlington pair' and to avoid DC offset, matching the hFE is a good practice.
I found the A42 at Mouser. But the 6571 was out of stock. The NTE website says NTE123AP is a cross-reference equivalent.
I bought extras of both. I found two A42 that are roughly the same hFE (95-105) but the newer NTE123AP are much higher (173-190).
Question: Do the A42 transistors need to match the hFE of the NTE123AP?
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