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DIY Stompboxes => Building your own stompbox => Topic started by: ljoe1969 on May 04, 2011, 06:27:30 PM

Title: Can I run 2 fx with one 9v battery?
Post by: ljoe1969 on May 04, 2011, 06:27:30 PM
i am just built the lpb1 and a electret mic power circuit.

i tried to run them in series with the electric mic out going into the input of the lpb1 and then out from the same battery.

i get mostly static crackle this way. when i have them on separate batteries then all is fine.

how can i connect them so that i can have only 1 box?

joe
Title: Re: Can I run 2 fx with one 9v battery?
Post by: blooze_man on May 04, 2011, 08:54:36 PM
Have you tried using an adaptor? Maybe there's not enough current from the battery for both circuits.
Title: Re: Can I run 2 fx with one 9v battery?
Post by: Mark Hammer on May 04, 2011, 09:04:24 PM
The combined current draw of those two circuits is much less than the average overdrive pedal, so you shouldn't have any difficulty running them on one battery.

Of course, the two circuits have to be wired up properly for that to work.
Title: Re: Can I run 2 fx with one 9v battery?
Post by: ljoe1969 on May 05, 2011, 09:39:19 PM
i tried them in series.

mic amp then booster.

mic preamp schematic

http://freestompboxes.org/viewtopic.php?f=13&t=3254

any suggestions on how to wire them?

thanks,

Title: Re: Can I run 2 fx with one 9v battery?
Post by: ljoe1969 on May 05, 2011, 10:38:41 PM
(http://i268.photobucket.com/albums/jj20/ljoe1969/th_micandlpb1.gif) (http://s268.photobucket.com/albums/jj20/ljoe1969/?action=view&current=micandlpb1.gif)
i tried just connecting the output from the mic to the input to the lpb1. i got static and such.

ljoe
Title: Re: Can I run 2 fx with one 9v battery?
Post by: mistahead on May 05, 2011, 11:41:31 PM
What I'd be doing at this stage (given that I'm fiddling around with a similar setup):
1. Confirm each works independantly again.
2. Confirm they are both eith + or - GND (if they're not it is probably not worth persuing further).
3. Link the GND's, Link the 9v test each's In/Out independantly.

If everything is still looking good at that stage link the Out from the first stage to the In of the second stage and turn knobs frantically if it doesn't immediately work (I do this a lot).

See how you go, I can't comment on whether or not impedance is going to come into play (not that bright on the topic) and I'm not that familiar with those circuits.
Title: Re: Can I run 2 fx with one 9v battery?
Post by: ljoe1969 on May 06, 2011, 01:14:36 AM
yes. both work separately.

i have them both in separate boxes.

thanks,
Title: Re: Can I run 2 fx with one 9v battery?
Post by: mistahead on May 06, 2011, 02:06:36 AM
Both in seperate boxes... so you'll need to be running the 9v's +/-'s both to both boxes... so a daisy chain setup sounds like what you are trying to accompish (or a simply Y split on the +/-'s).

That is assuming they both GND the same way (as I said not sure).