Connecting two opt's to act as one.

[mcgaag]

I have the luxury of owning 4 se opt's, all the same type, 2.5K primary and 8Ohm secondary.

I was wondering, is it's possible to combine 2 opt's to act as one push-pull opt? 5K pri, and 4 or 16Ohm secondairy?

Regards,
Rob

[Eli Duttman]

Rob,

A workable solution along the lines you want is to build 4X "identical" SE channels. Separate the channels into 2 pairs. The I/Ps of each pair are connected in parallel. The O/P trafo secondaries of each pair are wired in series. Use 4 Ohm speakers.

The method described above is not PP, instead it's "strapping". Also, the method requires that the O/P trafo secondaries float. If the secondaries are grounded, as is the case for GNFB, an alternate method ("bridging") is necessary. "Bridging" drives the I/Ps of each section with 180^o out of phase signals. The grounds of the 2 sections are tied together and the speaker is connected to both "hot" terminals. A 4 Ohm speaker is appropriate here too.