Power sag in fuzzbox?

[Mikkel]

Hello.
Being new in this soldering business, I'm glad to report that I've build my first.
Not to be too ambitious I started out with a pnp-Fuzz Face. As I was soldering
I used a battery for power. I kind of liked the sound, and being the first pedal I've
build and all, I put it in a nice case, put a DC connector and tried it on.
The battery however sounded better to me. It was pretty badly worn when I got
around to assembling the box (quite surprising. -It was a brand new Duracell and it
was plugged in no more than half an hour in all. I was "debugging" for a while there:
"where did the sustain go!!?!?". When it finally occured to me to measure the battery power
it was around 0.7V!) - (That's strange, I think).
Well, but it sounded pretty cool, and my question would be if someone could point me in
the right direction if I wanted to put some sort of "sag"-pot in(?) the pedal?
Thanks,
Mikkel

[Seljer]

wire a potentiometer (in the kiloohm range) as a variable resistor in series with the power supply, that should gets you lots of various half-dead battery sound

http://www.beavisaudio.com/Projects/DBS/

[John Lyons]

Search for skyripper in the Gallery. It uses a 50K linear pot in line with the battery
It's a nice control to get those low battery power sounds.

John

[Mark Hammer]

Look here for an interesting idea: http://www.generalguitargadgets.com/index.php?option=content&task=view&id=174&Itemid=200

Charles Fischer used an LM334Z current regulator to variably "starve" the invertor section used for the clipping element.  As I understand it, if you apply a largely input voltage to an amplifier, the amplifier will require more current to put out that input voltage times the amplification factor.  Regulating, hence limiting, the available current is tantamount to the power supply "running out of" juice with which to amplify.  I don't know if this precisely replicates sag, but it sure comes close to the definition.  Not sure if you've ever had a purely analog transistor radio running off batteries, but as the batteries get low, you can continue to run it at low volumes.  Turn up the volume a smidgen past that, though, and the unit starts to show audible signs of struggling.

You will note that the current limiting in this particular circuit is restricted to one specific stage, while the remaining stages all have unrestricted access to whatever current power supply is normally capable of supplying (in the absence of current regulation).  You will also note that the relationship between current regulation and perceptible sag will depend very much on the properties of the specific semiconductor involved; i.e., the same regulated current level would be expected to have greater impact on a device with higher current needs than one with lower current needs.

[petemoore]

  Here's somethings to check out !!
  A 'Punisher' variably starving a MU Amp depending on input signal level.
  EZ test on any circuit uses LM317 voltage regulator, nice to have around sometimes anyway.
  Or 'sag' as in sag of like Tube Amp PS.

[joegagan]

I ended up selecting 50K because I sometimes use fuzzes as a gate after heavily boosted signal, anything less than 50k did not actually shut the signal off between notes. Makes it a little harder to dial in but essential for the way I use it.

[Mikkel]

Thanks for the input!
I'll get soldering tonight

Mikkel