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DIY Stompboxes => Building your own stompbox => Topic started by: GibsonGM on July 20, 2006, 09:57:26 AM

Title: DC on output??
Post by: GibsonGM on July 20, 2006, 09:57:26 AM
Hi,  looking for some advice from a guru here....I've measured a couple of DIY pedals I've built, and find that on the output I get something like 5mV DC with effect on 10 and no guitar input.   They're built right - blocking caps and all - and work just fine, and it could be something with my DMM interpreting AC as DC, I guess.  Or cap leakage. 

Does anyone know if that small level of DC is 'bad' for an amp?  If not, what DC level would be harmful?   I've had a case or 2 of trying out a new effect with a short, and feeding a few volts to the amp input, luckily without any damage, but it's scary, LOL!  I use the old SS mini Marshall for testing....  ;)

Thought this might be an interesting topic, and haven't found it by searching....thanks
Title: Re: DC on output??
Post by: petemoore on July 20, 2006, 10:00:32 AM
and it could be something with my DMM interpreting AC as DC, I guess.  Or cap leakage.  
  must be, or, I can't think of anything else it 'could be.
Title: Re: DC on output??
Post by: scaesic on July 20, 2006, 10:03:54 AM
i'm no guru, but i'd say 5mV is nothing. thats 0.005V. it could be that your dmm has a large variance, and the fact that theres some a.c going down it.