Weird question re: balanced connection

I second Kijanki’s good comments, and I would add that in addition to the possibility of over-stressing the amps due to the halved impedance each of them would see, I’m not even sure that you could turn the amps on and off without creating at least a small risk of damage.

As you are probably aware, running a tube amp that has an output transformer unloaded is not a healthy idea, especially if a signal is being put into it, but conceivably also during the startup and shutdown processes even if no signal is present. Transients that may occur in the amplifier circuitry at those times might in effect create a brief “signal.” And in the configuration you are proposing whichever amplifier in each channel pair is turned on first or off last would in effect be running unloaded for at least a brief amount of time.

Also, although this amp is not bridged (it uses two 845 tubes in a parallel SET configuration), I’ll mention that combining two bridged amps into a balanced pair configuration would be a sure invitation to damage. Combining two amps into a balanced pair configuration requires connecting one output terminal of one amp to one output terminal of the other amp (with those terminals not being connected to the speaker). With amps having single-ended outputs it would be the common or ground terminals that are connected together. But with bridged amps the result would be that output signals which are inverted relative to each other would be shorted together. Definitely not healthy!

Regards,
-- Al

Ralph, that's excellent and useful information, of course. But I'm not sure whether or not you noticed that the question was not about monostrapping or paralleling. It was about the possibility of configuring two pairs of tube monoblock amps having unbalanced signal paths into the functional equivalent of a pair of *fully balanced* monoblock amps.

Kijanki & Zd, thanks very much for the kind words.

Best regards,
-- Al