D'Agostino Momentum amp melts down

Taken form Sterophile review of Dartzeel amp

"I ran it at 1/3 its rated power into 8 ohms for 60 minutes, which thermally is the worst case for an amplifier with a class-A/B output stage. At the end of that period, while the shrouded heatsink on the amplifier's rear was too hot to keep my hand on, at 63.5°C/146°F, the top of the enclosure was ":

That is an extreme situation. This is probably an isolated incident with no real world application. No other reports that I a aware. It was tested by Martin Colloms.

Atkinson *should* have run the 2nd exactly as he ran the 1st. If it blew up, he should report it. What is it with these guys giving a pass on this gear. If it can't cut it, WE NEED TO KNOW ABOUT IT!!

-RW-

i thought that was there policy.

A quick internet search shows that the following amps did not, or could not pass the Stereophile administered 1/3 power test: Bryston 14BB-SST, Arcam Alpha 10P, McIntosh Mc1201 and Pass X1000. I can only imagine that a thorough search would turn up many more examples.

Not passing this test doesn't mean an amplifier is bad. It could mean underspecified heat sinking, very high bias settings or very conservatively set protection circuitry. In the case of the D'Agostino I suspect the copper heat things are an attempt to keep the amps weight manageable. Remember, the 1/3 power test does not reflect real world operating conditions. It's designed to stress a solid state amplifier in order to then measure distortion components.

Rhljazz, what exactly is your agenda in starting this thread? Nowhere in the Stereophile article does it say anything about a melt down. The amp stopped working. It didn't melt, catch fire or explode, yet you keep using language suggesting some Chernobyl style event. You actually seem to take pleasure in the amp's malfunction. The German language has a multisyllabic word for what you're exhibiting.