Adding a Voltage Sag?

[wesayso919]

Hi. Newbie here. Id like to add a voltage sag to a few pedals starting with a wolfshirt. How would I go about this? Are there any schematics or pages with info dedicated to this?

[Betty Wont]

Hi. Newbie here. Id like to add a voltage sag to a few pedals starting with a wolfshirt. How would I go about this? Are there any schematics or pages with info dedicated to this?

You wire a pot as a variable resistor on your 9v+ before it goes into the board. 1k-100k should work, find the one that gives you the range you want. Some pedals wil just shut off if you starve them. Experiment!

[gtr2]

Remember if you daisy chain pedals this will affect all the pedals it's connected to.

[Brach]

The traditional way of doing this is to use a variable voltage regulator.  The LM319 will work at the cost of around 2.5V (meaning the input has to be over 2.5V of the input).  This would work if you are wanting a really low voltage for a pedal, or are powering the circuit with something larger than a 9V supply.  A better solution is to use a LDO (low drop out) adjustable voltage regulator.  I've used a LP2951 for this exact purpose in a pedal power supply.  This IC has a dropout voltage of around 350mV, if i remember correctly.  The datasheet has a formula you can use to determine the external parts for the range of voltage you want to pass.  The package i used was a surface mount device...I don't know if it comes in a TH package.   As always, when using these types of devices, mind the current draw of whatever you're powering.  The picture is a snapshot of my schematic of the regulator circuit.  I don't recall, off the top of my head what the output voltage range is programmed to be via external resistors.

[wesayso919]

Thanks. Good stuff here

[MJ_Sound_Cubed]

Hi 

Depending on the project and device there are several ways.

One would be the potentiometer method mentioned earlier in line with the power supply, in some fuzzes in the bias supply.

Using an IC is a good method if it is a higher power project.

Regards,
MJ