Dying Battery Simulator is not doing anything

[mr.adambeck]

I wired up a "Dying Battery Simulator" exactly as shown in this drawing from the beavisaudio.com site:



I've double, triple and quadruple checked that I have it wired right.  However, it doesn't seem to do anything.
As I turn the pot, it sounds like things are cutting out, then once I stop turning the pot, things come back sounding exactly as they were before, no matter how far I have the pot turned.
To test that I wasn't crazy and that this wasn't doing anything, I took it out of the stompbox and wired it up to an LED on my breadboard, figuring that if the voltage was decreasing, the brightness of the LED would decrease as well.  (Right?) 
The LED is staying the exact same brightness no matter what.
I'm using a B10k Alpha brand pot, and like I said I've checked a million times to make sure I have it setup properly.  Is it possible my pot is bad, or is there something wrong with the illustration, or am I simply missing something here? 
I only have one 10k pot to try it out on (the only other small value pot I have around is a B1k, I don't know if that's too small), so I don't know whether it's the pot or not.

[darron]

i can't imagine a pot becoming a complete short if it's still passing current, unless you've somehow shorted to the casing. the best way would to check would just be to take off the wire going to the circuit board and use your multimeter to measure that it is actually creating resistance. the output voltage shouldn't change much but the available current would.


10k on a high efficiency led that already has a limiter might not do much, but it should be barely noticeable. i'd even suggest you try bumping the pot up to 100k maybe. 1k will not help you at all.

[slacker]

What circuit were you connecting it to? With some effects it might not do anything much.

[DWBH]

Why not use the pot as a voltage divider?

[darron]

Why not use the pot as a voltage divider?

i think the idea is more to reduce the current, not voltage, though it will drop the voltage a little also to a dying battery level.

i reckon 100k or 1m might help out.

[DWBH]

But when you measure a dead battery, it doesn't measure 9v.

[mr.adambeck]

I am using it in a Bazz Fuss circuit.
I was told it should sound good on this circuit.

[petemoore]

However, it doesn't seem to do anything.
As I turn the pot, it sounds like things are cutting out
  The two lines seem to be contradictory to me.
  Bazz Fuss..maybe it just cuts out when you turn the pot, the bias is tweeky on that one [I forget...]. Are you adjusting the pot very slowly, perhaps it jumps into an unbiased state rather abruptly, I would think it'd make the note attacks sag slightly then 'duck out' on hard attacks as the 'dead battery effect is increased, cut out entirely.
  So what does the voltage read when you turn the pot, does it change ? That'll tell you if the dead battery effect is working.
  LM317 adjustable voltage regulator is worth considering for this type of effect.

[slacker]

Which version of the Bazz Fuss have you built? If you've used the version with the 100k collector resistor, then adding an additional 10k in series with it, which is what "Dying Battery Simulator" will do isn't going to make a lot of difference. Even if you've built the version with the 10k collector resistor it won't have a huge effect. I would use a 100k pot instead of the 10k for that particular circuit, that should do something noticeable.

[mr.adambeck]

okay, so I bumped the pot all the way up to a 500k and now it sounds kind of gated on one end of the pot.  I guess the way it acts on the bazz fuss just isn't that extreme/noticeable!

Thanks for all your help!

[Scruffie]

I don't suppose it's possible the taper (linear or log) of the pot is wrong? Or the pot is damaged...?