Originally Posted by snyderkv
The question is in regards to an AVR with single transformer that goes into protect mode when driven by martin logans at high volumes. (from reviews online)
As Mr. Ball seems to be suggesting, amplifier protection circuits are divorced from power transformers by several layers of circuitry.
Amplifier protection circuits vary from amplifier to amplifier so it is hard to say much more with 100% generalization.
In general they monitor the current being drawn from the amplifier, and take steps to keep certain limitations from being exceeded. Some monitor both voltage and current, but usually the voltage monitoring is used to modify the current limiting, not actually limit just the output voltage of the amplifier. Excess current drain can overheat and damage amplifiers. Amplifiers tend to be self-limiting when it comes to voltage so there is no further need to limiit voltage.
Would stepping up to the dual transformers with 50% more power help a tad?
No except that amplifiers that can put out more power can generally also put out more current. Whether the extra current supply comes from one larger transformer or two smaller ones matters little.
I listen at low volumes so if the protection ceiling improved a little that would be great.
Protection circuits tend to be like brick walls. If you stay even just the tinyest distance from them, then for all intents and purposes they might as well not exist.
I'm guessing no because the speakers aren't in series so the impedance never changes.
It would be parallel connections that could possibly cause a problem. Series connections if anything reduce the maximum current drain.
So five 6 Ohm speakers would still present 6 Ohms to the receiver?
Yes. The power transformers are so completely divorced from the amplifier speaker terminals that they are practically irrelevant when it comes to listening to music. OK, they have to be there and they need to deliver enough power. However, the amount of power that is needed is often less than it may seem.
The key thing to remember is that power ratings of amplifiers are generally specified based on bench tests with resistive loads and steady pure test signals. In the US this is done for legal reasons dating back to the 1960s and 1970s when we did not understand many things about audio. Music puts a much lighter load on amplifiers than test tones.
As far as Martin Logan speakers go, some of their electrostatic speakers are very unusual loads, and there is little that can be discerned about driving them that can or should be transferred over into expectations related to more typical kinds of speakers.