Premature burst when she's turned on . . . uh, from my Foreplay I mean.

danderby · 1640

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Offline danderby

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I built a Foreplay some years ago (5?) and perhaps because of my poor workmanship, when she turned on, there was a short but very strong signal then she would settle down.  I almost toasted my crossovers once when I forgot and had the amp on when I powered it up.   Is that normal for a Foreplay of that era?  Is there a 'cure' (besides not being forgetful)? 

Also, I'm considering building a B'head phono pre at the moment. Do these units have the same phenomenon?

Thanks, Dan



Offline Paul Joppa

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There will normally be a "pop" as the power supply comes up and the output coupling capacitor charges up to operating voltage. The simple solution is of course to follow the rule, turn the power amp on last. The fancy solution is a relay on a time delay circuit - new power supply, PC board, and relay.

Paul Joppa


Offline Grainger49

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I like the LOW RIDER FP 2.

The turn on and off sequence is kind of a standard thing.  You should allow 10-20s for the FP 2 to warm up and turn the amps off about 10s before the FP 2.  There might be a turn off thump too.