McCormack DNA-1 Protect Mode light glows dimly


I have a McCormack DNA-1 that I purchased new in 1992 (IIRC). It has been in storage for a while, but I took it out today and hooked it up to a pair of new-to-me PSB Stratus Golds. The front end was an old Marantz receiver using the Main Out taps and a 1987 vintage Sony CD player. The sound was INCREDIBLE!!! However, after an hour or so at reasonable volume (since I live in a condo)(1/4 turn of the voume knob)the amp cut out and the red light of death appeared. I removed the top and inspected all five fuses (4 inside plus the main power fuse) and all are good. I let the amp sit, then plugged it back into power only (no inputs, no outputs). Now, the red protect mode light does its usual glow for 20-30 seconds then fades out. But, it does not fade completely dark! It still glows dimly. What could this be an indicaton of? Is the amp safe to use?

Thanks in advance,

Bob Martin
wz4rfv
Hi Bob,

Nice to hear that you got your DNA-1 back into service and are enjoying it. The protection circuit monitors DC at the output and shuts-down the amp if it exceeds a certain level. It is possible that it was just doing its job - it may be that both the DNA-1 and your Marantz receiver needed to warm-up a bit and get all the electrolytic caps re-formed to minimize leakage currents and get everything working properly again. In any event it seems to be working now, so I will hope it keeps on delivering good Christmas Carols for a long time.

Best regards,

Steve McCormack
SMc Audio
Well, good news (so far)! I plugged the amp in last night and the Protect Mode light acted normally. So, I hooked the amp up and played through three CDs without a recurrance of the issue. Let's keep our fingers crossed that it was just a fluke!
If you are patient, you will likely get a direct response from Steve McCormack. He usually shows up here from time to time. My concern would be that depending on how long you've had it in storage, the capacitors may have dried out and that since you did not bring the voltage up gradually, that caused a failure.