Typical power consumption of disengaged pedal

[shrubbery]

I've just built my first pedal, I'm new to this kind of gear so I have no way to tell what is typical for pedals.

The pedal is true bypass GGG WHRL (http://www.generalguitargadgets.com/effects-projects/distortion/red-llama/) and it draws power even if I switch it off (2mA off and 6mA when engaged).  The battery would last maybe a week in a setup where input jack is always plugged in.

Is this a design flaw or is this considered normal?  Are there any (passive) fixes, I can only think of sacrificing LED for disconnecting +V?

On the practical note - there are some people who swear by batteries, do they unplug everything or do they replace batteries every week?

[knutolai]

This is normal. You wouldn`t want to disengage the supply voltage for the audio circuit when in bypass because of potential audio artifacts when going from bypassed to active. Depending on the series resistor, in some cases the LED is the most consuming part of a circuit (true for some simple 1-transistor designs).
In my opinion just stop using batteries. If you need further persuasion read this:
http://www.beavisaudio.com/Projects/badBattery.htm

[shrubbery]

Thanks for the confirmation.  I already don't find batteries convenient so this is definitely one more reason to keep it outside when putting the screws in...

[bool]

It's a fact of life. Your pedal actually eats a pretty small amount of current.

But when engaged it apparently eats 3-times the idle current. Have you checked and optimized how is your LED connected? I ass-ume it's your "ON" LED that causes the current consumption to surge up. I would increase the led resistor to ease up the current draw ...

Things like power consumption are even more tacky when designing onboard guitar electronics. And if you count in a sad fact that a true "class-A" tone demands a bit more current than opamps if you want to make it reasonably "phat", there you go ...

Things like these add up.

[shrubbery]

I didn't change anything from the GGG schematic and didn't measure current through the LED so it's possible it eats up the rest of it.  It was just the constant battery eating what bothered me, I know how easily that can add up...

[bool]

I see. If you want to further optimize the current consumption, a general rule of thimb is to get in possesion of the brightest possible LEDs you can get - and then increase the (current limiting) resistor so it just lights up sufficiently to maintain a satisfactory visual feedback when the pedal is "ON". If you're into such things after all ...

[GibsonGM]

If you know what resistor you used for the LED, you don't have to measure the current, it is simply 9v/your resistor value.  It probably (most likely)  DOES account for the additional current, unless there's some OTHER thing that goes on when you engage?  (no)

I tend to run LEDs around 8-10mA, as a rule of thumb. I don't spend much time 'dialing them in', lol.    So, my pedals probably draw 15mA or so when engaged, and say 5mA when bypassed.  To me, that is more than acceptable.  If I use batteries, I can do probably 2 to 3 gigs before replacement.   Same problem as you - I moved to a 9V power supply long ago, and now i don't worry about a thing.  IMO, batteries offer too many chances something will go wrong, anyway, and you don't want that in a live situation.

Well, I do still have ONE power issue - my wah, vintage 70s so I didn't put in a power jack, and it still eats batteries, ha ha!  Every 2nd gig, gotta change it out...

[Mark Hammer]

If you are committed to battery power, for whatever reasons (and I can think of plenty), note that you can provide battery power to the external power jack.  Provided your battery cluster can provide enough current, you can power a whole pedalboard with it.  If you are committed to internal 9v batteries, and don't want to tear down a pedalboard each time you stop playing, then I would suggest getting a handful of the appropriate plugs (2.1mm or mini-phone type), and simply plug one into the external power jack of each pedal at the end of a gig/practice/session (assuming you've left yourself enough space to do so).  The plug disables the battery, and if the plug isn't providing any power, then the pedal is essentially in the same state as if you've unplugged from the input.

[Philippe]

cars, flashlights, toys, radios etc. all drain batteries even if they aren't turned on or in use (although the drain is smaller when compared to actual/operational usage). use the plugs as mark suggested or remove the batteries when not in use...a real drag depending on the number of fxs.