9V through 3PDT

[workroom]

I have an effect which uses batteries too quickly, but I want to keep it battery powered. It was setup to break the batteries connection only when unplugged. I rewired the switch to break the battery connection when bypassed. It seems to be good so far. So now the battery disconnects when bypassed and also when unplugged. Is there any reason that I shouldn't run the battery through the 3PDT?

[antonis]

I think this was my first post in this forum...

If you do some "search" you'll find some very analytical threads..
(my PC is very slow to do it now..)


Or else, wait for Mark Hammer and RG Keen to reply with "This question appears more than once in a year" being ther first sentence..


edit: I've found it http://www.diystompboxes.com/smfforum/index.php?topic=108606.msg990286#msg990286

[MrStab]

if it works, it works... but have you tried it through a loud amp? that's the true acid test.

i say this because before i knew better, my first build (an active looper/blender) had the power on the same switch as the signal, and it made an almighty pop. regardless of the volume. it wasn't like the usual LED popping - it didn't sound at all healthy. i didn't notice it as much on my smaller test amp.

one other thing to consider is any delay in power-up time as caps charge etc.. I have a Korg tuner that supposedly uses less than 1mA when bypassed, so maybe it's a perfectly fine approach - though that mutes the signal when activated, and I don't know much about that circuit, so not really a good comparison.

test it under various conditions, different gain going in & out of it, different amp levels, maybe check for a voltage spike on the output as it's turned on... and if it's still fine, go for it! screw the naysayers!

[antonis]

screw the naysayers!

I like your spirit...!

[Mark Hammer]

"This question appears more than once in a year"     because it does.

Most pedal designs will include a medium-to-largish value cap between V+ and ground to smooth out any perturbations on the power line that could show up as noise.  The trouble with disconnecting and connecting V+ is that it can allow that cap to discharge, and then need to recharge before the circuit becomes audibly active again.  It can be disruptive by imposing a moment of silence before the effect starts to actually work and you can hear the instrument again.  That's why you won't see very many pedals using a stompswitch to do what you're proposing.

I suppose what a person could try and do is use a stompswitch to reduce the current draw in a sort of "standby" mode.  So, in bypass, the circuit remains connected to V+, but there is a series resistance between the battery and the rest of the circuit, "starving" it of current, but still permiting the cap to charge up while in the standby mode.  Then, when you engage the effect, the stompswitch bridges that resistor, so that the circuit and smoothing cap are directly connected to V+.

I have to emphasize that I've never attempted this.  Moreover, what would be an appropriate current reduction for THAT particular circuit, so that it conserves the battery but doesn't interfere with effect functioning, is not something I can guess at.

There are other things one can do to stretch a battery further.  Perhaps it is possible to use low-power op-amps if the circuit uses op-amps at all.  And it is sensible practice to use the brightest status LED you can, so that you can stick a bigger current-limiting resistor in series with it and shrink how much current it pulls when the effect is on.  I like to use super or ultrabrights (10,000mcd rating), mount them in a manner that yields the greatest visual contrast (black plastic bezel or simply a dark chassis colour), and adjust the current-limiting resistance until it's just bright enough to do the job.  Someties that can easily chop off a couple of ma in current draw.

[newperson]

another route if you really want to keep it battery powered, use a larger battery source.  i am guessing it is 9 volts?  you can pair together 6 AA batteries to get higher overall mA.  Get a set of Eneloop rechargeable and you will good to go.  if they don't fit in the same case you can make a battery pack external or to be extra fancy put them in a little pedal box.

http://www.allelectronics.com/make-a-store/item/bh-361/battery-holder-for-6-aa-cells/1.html
something like this (if it will fit in your box) already has a place to snap your 9 volt snap right onto the case.

[bluebunny]

Out of interest, what effect is it, that it eats batteries at such a rate?

[newperson]

Out of interest, what effect is it, that it eats batteries at such a rate?

i like this thought also.  could be something wired wrong draining the voltage.

[workroom]

Sorry for the delay.

It is Colin Rafael's parallel universe



Built into the body of my guitar, wired to a switch to go directly to oscillation.  I eliminted the effect controls over gain, eq, and volume and kept the control over frequency. I am pretty sure that just running the LM386 is a battery killer.

The effect is great. There doesn't seem to be any problems running it wired like I have.
My other thought is to put it into a Wah enclosure. Quick easy control to the frequency pot is crucial.