As previously stated, Mr. Atkinson merely quoted from the manual.The wording was not correct in the article, nothing more nothing less, it was misleading as to how the thermal protection functions
Except of course for the Stereophile testing.
5. In the event the MC501 over heats, due to improper ventilation and/or high ambient temperature, the protection circuits will activate. The Power Guard LED will stay ON and the audio will be muted. When the MC501 has returned to a safe operating temperature, normal operation will resume.
There's the simple answer. Thanks!The Power Guard LED will stay ON and the audio will be muted.
Concur. My MC1000 lit a PG lamp for a capacitor failure in a powersupply circuit not directly related to PG operation. Amp would drive a signal on meter no PG light but with speaker load connected a PG light and no signal out.No argument here - see post #109.
Thus the emergence of thermal track soon after. Engineering progression to meet legislative restrictions. Like smog controls in 1974 forcing fuel injection and computer control advances in automobiles to get power and performance back without compromises.This is a follow up manufacturers comment to another Mc review.
https://www.stereophile.com/content/mcintosh-mc1201-monoblock-power-amplifier-manufacturers-comment
Charlie Randall (McIntosh Laboratory)
"A comment about the 40-minute operation at 1/3 power: This is done to keep the top cover of the amplifier from exceeding 65 degrees C, which is a requirement for CE certification. The unit is designed using parts that are safely operated at 80 degrees C and higher. Allowing the unit to shut down at 65 degrees C is extending the life of the product. The only music material that is really available today that is compressed enough to represent 1/3 power would perhaps be an FM radio station (if you could imagine listening to 400W continuous). It is reported that the amplifier needed to be reset when this occurred—the reset is automatic. Once the amplifier overheats, it mutes the input; after it cools down, it then unmutes automatically. There is no reset required by the user"
Damn! ...and I was going to buy these new amps and hook-up old cheap speakers just to blow them up.
I guess power guard won't let me...
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Having driven 1200 watt per channel speakers 8 ohm and 4 ohm speakers that suck up 1000 WPC ohm with MC2500s bridged. I can attest the fans can be heard when passages go quiet. The fanless quad balanced MC1000 does same loads without the fan, and is quieter in upper registers during peaks. If I could run MC2500 out of listening area difference maybe less. I am not convinced light fog in highs was not fans. Thing is extended 300 to 400 WPC peaks will cause fans to run intermittently and lessen experience. So yes MC1.2KW would be my next choice.If anyone would read Crowns and QSC latest owners manuals they have found and confirmed even under the most demanding live concert requirements the average duty cycle for an amp is about 1/8 of its continuous just before clipping rating. Thats far below the 1/3 power test of the FTC requirements. So for music unless your driving the amps into compression by activating the PG function you will never see the 1/3 continuous power condition. Older Mac amps like the 2255 were designed to run all day at any level with out an over heating issue with adequate ventilation, but they didn't have the current reserve or the dynamic capabilities of the latest amplifiers including the MC501. Todays amps are designed to handle signals with a much higher crest factor driving more adverse loads than amplifiers of the distant past. Which would you rather have a 2600 with its noisy fans, or a 1.2 K amp to drive a pair of 1k speaker or a S7 from Magico. I'd take the 1.2k myself. Neither a MC2255 or a 7300 will drive a 4 ohm load from its 8 ohm tap at a higher than rated power level and exceed specs like a MC 501.
Digital images of your results will help strip ammo from the Mc snipers.Sorry,. we keep derailing this thread, but there is a good discussion going on here....
I think what McIntosh does is underrates their amplifiers, the MC452 is a monster, they say its 450watts per channel, but really it can easily do 900 watts per channel for short periods.....other manufacturers might say it was a 900watt amp? Who knows...
In fact, you know what, I am going pull my 452 out of its hole here and run some tests on it to see what it can actually do!!