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Help? Possible problem with my McCormack dna-125.

I recently bought a McCormack dna-125 here on Audiogon and I enjoy its sound very much. However, on the weekend when I crank it up (0.0, equal to 12 o'clock on a dial) for awhile the amp has twice just stopped abruptly in mid song after about 30 minutes at this volume. The led goes out so I assume the power is interrupted so I immediately turn it off. The next day when I turn it on it plays as if nothing ever happened. Because it only does this at higher than normal listening volume I am thinking a clixon fuse or something like that is knocking out the power. I'm thinking this may be heat related but I often leave the amp on for many hours at slightly lower volumes (15.0-10.0, 10-11 o'clock) without issue. I crank it up a little higher once a week or so and this doesn't always happen. Has anyone had similar problems with this amp and if so, what did you do to remedy it?

McCormack dna-125
McCormack rld-1
Esoteric p-700
Parasound t-3
Unity Audio Cerious 7
Pioneer pl-530
Entech nc205.2
APC h-15
Cerious Technologies interconnects
Home made silver-clad copper wire speaker cables
silversurfer0116

Showing 1 response by stevemcx

stevemcx
166 posts
 
The RLD-1 volume display reads actual attenuation in dB, so 0.0 is unity gain (output voltage equals input). Given that 2VRMS is industry standard for max output level on most CD players and the input sensitivity for the DNA-125 is 1V for full output, this would suggest that you could be well into clipping, at least on peaks. So it is possible that you might be triggering the thermal cutoff circuit after playing at this level for a while. The thermal switch is set so that it cuts off around 80 degrees C, which is extremely hot - enough to burn you quickly if you touch the heatsinks. It should be easy to check for this by monitoring the heat sink temperature as you crank-up the volume, but it seems most likely that this is what's happening.

The DNA-125 has plenty of power for most speakers in most situations (and also runs fairly cool typically), but it may be that you are pushing it to its limit.

Best regards,

Steve McCormack
SMc Audio
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