SE stereo / PP mono block schematic choices

[speakerfritz]

looking to build an SE stereo amp that can be switched into PP mono block mode. Came across this schematic which was clean and simple. For PP mono block mode, would just need to add a phase inverter and run a bridged speaker connection.


If anyone has any other schematic recommendations, would be interested in reviewing. Thanks for any input.

[DF96]

This question seems to come up from time to time. The main issue is why? SE needs a more expensive transformer than similar PP, yet coupled dual SE will still give inferior results to real PP because of poorer OPT primary coupling. You end up with the disadvantages of both systems. Why would anyone want to do that?

[speakerfritz]

Originally Posted by DF96

This question seems to come up from time to time. The main issue is why? SE needs a more expensive transformer than similar PP, yet coupled dual SE will still give inferior results to real PP because of poorer OPT primary coupling. You end up with the disadvantages of both systems. Why would anyone want to do that?

Here's another schematic of a stereo SE amp, that can be bridged and when bridge, is in mono PP mode. The specs on this amp is very good. So while it could be problematic, it has been done.

As far as why do I want to undertake this......I think this feature provides greater flexibility. For example, you could have 2 mono blocks, or with the same foot print, 4 SE channels in case you wanted to bi-amp a pair of speakers so equipped.


But certainly, I'm interested in the pit falls, so I can determine what the technological requirements would be to mitigate them.

[pieter t]

Originally Posted by DF96

SE needs a more expensive transformer than similar PP, yet coupled dual SE will still give inferior results to real PP because of poorer OPT primary coupling.

As long as the bridged configuration works in pure class A (both tubes conducting during the full cycle) I don't see too much of a coupling problem.