Torn between two amps

I agree with Stan. I'll add that the effects of a y-connector arrangement will be highly dependent on the output impedance of the preamp. The lower it is the better.

The preamp will see a load impedance that is equal to the product (multiplication) of the input impedances of the two power amps, divided by the sum of those two input impedances. If the two power amps have equal input impedances, that corresponds to a combined impedance of 1/2 of the input impedance of each amp.

That combined impedance should be at least ten times (and very preferably 20 times) greater than the output impedance of the preamp at the frequency at which that output impedance is greatest (which is likely to be 20Hz, unless the preamp has a dc coupled output, meaning no capacitor in series with its output).

Also, the capacitances of the cables running to each amp will sum together and possibly introduce some amount of upper treble rolloff, if the capacitance per unit length of the cables is high and the cables are long and the preamp output impedance at high frequencies is high.

Regards,
-- Al

Consider a patch bay. You will need to plug and unplug but it is allot easier.

"feelin' like a fool"?

One could buy another pair of speakers and too.

The overlooked item here is both amps are tube amps.

These switch boxes, such as the Niles or some others do not place a load onto the B amp. Only on the A side.

Meaning neither amp should be energized if no direct connectivity is made to an existing speaker load.

Thus somehting like the Niles unit I investigated recently by talking to Niles support dept. will work, but each amp will ahve to be turned on only after the switch box has selected the amp to be used. the former amp of course must be switched off, prior to making the swap too.... as recommended by Niles.

Niles supp also said this consideration is not nearly so critical as with SS amps.

the 'purist' factors are always going to be in play around here. the real question is what's more important to you now?

Some possible subjectively apprent loss in audio quality, which has yet to be determined, or that ease of use aspect

For about $100 and two more short pairs of speaker cables, you'll find out. Do look at the Niles SP1 however.

i doubt the actual possible loss will be quite so serious that you'd trash or resell the item though... but you could of course and wind up with some exp and no terrible financial short fall.

Neither amp should be energized if no direct connectivity is made to an existing speaker load.

Excellent point, Jim. A tube amp, or at least a tube amp that has an output transformer, should never be operated without a speaker load.

I believe, though, that that may not apply to an OTL. But as a matter of good practice, and not taking any undue chances, I would avoid doing so anyway.

Best regards,
-- Al