2. amps-preamps
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ARC SP-6 Warmup time

I just bought an Audio Research SP-6 preamp. It takes about ten minutes after powering on for the power lamp to stop blinking and the unit to start passing signals. Other than that it sounds perfect on all inputs. Is this at all normal? Does it indicate something is about to fail? Ten minutes to warm up is more than annoying.
richardp01
hifigeek1
770 posts
 
Jeffrey, the circuit diagram says longer and can cause a thump if the mute releases early. The B and C preamp versions have a very long DC time constant and so it takes a while for it to stabilize. If your preamp is releasing after one minute, the cap in the timer circuit is the wrong value and releasing too early.
markpao
519 posts
 
I've had the SP9, SP11 & SP14 and none of them ever needed more than 30-60 seconds to end mute mode. Agrre with others that you should call ARC and send it in.
exocet954
98 posts
 
From the SP6B owners manual. Page 6. Warm up timer mutes the SP6B outputs for 2 minutes after the power switch is turned "ON".
Post removed 
hifigeek1
770 posts
 
Yes, as I said earlier and I guess it never made it to this thread; Because the SP-6B/C have long DC time constants, in order for the circuit to stabilize, the timer should not release after one minute or you might hear a thump and watch your woofers move in and out for a few cycles. It would be especially dangerous if you were using a DC coupled solid state amp. Usually the cause if the timer releasing early is the wrong value cap in the circuit. The circuit diagram I believe shows 2mins. 35 secs. with the right value capacitor. Minor changes to that time are strictly a function of the tolerance of the cap.
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