One output stage - two transformers

[audiox]

My colleague called me a few minutes ago. He needs to rise the overload level of a transformer balanced output stage by 6 dB. An obvious solution would be to change the 1:1 output transformer to 1:2 but unfortunately he doesn't have one and the system must be ready at the end of the day. But he has some original spare parts and his solution was to add an another (identical) 1:1 transformer and connect primaries in parallel and secondaries in series. He was a little bit worried if it is a good idea or not.

I must admit that I have never thought that kind of alternative. As usual it is easier to consult transformer specialists here than use my own brains.

Obviously it increases output impedance and deviation of frequency response, but I was wondering if there are any other drawbacks.

 

[abbey road d enfer]

It does exactly what you say and also increases the LF load on the electronics (lowers the LF impedance), but it works. If the xfmr's are identical, this will improve output CMRR by 6dB.
This can be used as an advantage by configuring the xfmr's in humbucking mode, just by orienting the flux lines in opposite directions, either by simply rotating one of the xfmr's by 180°, or by connecting one in opposite direction.