Current limit onset definition?

P.S. to my previous post: I found some rear panel photos of the DMA-180, which although difficult to read I believe indicate that the AC line fuses for 120 volt operation are 6 amp fuses, not 4 amp fuses as indicated at the Spectral website. That seems more consistent with the 683 watt 2 ohm continuous output power rating (6 amps x 120 volts = 720 watts AC input), although still marginal at best, as I would feel safe in assuming that the amplifier is not close to being 683/720 = 95% efficient.

Although in the photos it's hard to tell for sure if the 6 is really a 6, and not an 8. 8 amps x 120 volts = 960 watts. 683/960 = 71% efficiency, which roughly speaking would seem to be in the ballpark of being reasonable.

Regards,
-- Al

Thanks very much Al. On my DMA180 the fuses are specified as 8 amp for 100 and 120 volts. 4 for 220.
I bought my Spectral and MIT gear based on discussions with MICHEAL PERCY, who sells components via his website. I am reminded that he was especially knowledgeable and helpful. From my experience one can be very confident in dealing with Michael. I would not hesitate to send a bank draft or money order-with my order. He is a reliable gentleman.

The current rating is the amount of current that flows when the power supply is shorted out for 10 milliseconds. As Al pointed out, it has nothing to do with the power or the current that the output section can make.

The rating is really only there to show how the power supply is built up, and it is without question confusing! For example, you might be surprised normally to find that a tube amp (and for that matter an OTL) has the same rating. But we are not talking about anything to do with the output; simply the power supply itself. more:

http://www.atma-sphere.com/Resources/Common_Amplifier_Myths.php

The "6" is indeed an "8" - 8A. see this clear picture of the back panel at http://hifi.myinsales.ru/collection/usiliteli/product/spectral-dma-180

Newer amps have 5A fuses.

Clearly the 40A figure has nothing to do with power draw...