Vr on a Big Muff

[m_charles]

Hey Everyone,

I have a buffer I want to pop into a muff, but I got a bit unsure on the Vr I need from it.

My first thought was the collector of Q1, Q2 or Q3. But then I checked them and they were all a bit different in their voltages. I'm assuming this isn't too critical, but I thought I'd ask someone just in case I've got it all wrong.

thank you in advance!

chuck

[John Lyons]

You should add a Voltage reference circuit.
10k to ground, 10k to 9v with the junction between the two being your 4.5v voltage reference.
Connect the + of a 10uf cap to this junction then to ground.
Voila!

If your buffer is an input buffer then connect a 1M resistor in between the VR and the input pin of the IC.

john

[m_charles]

thanks john, you've helped before...

So what would be wrong with taking my Vr from the muff circuit? Is there some negative I'm unaware of?

This isn't a separate add on, I'm building it as a part of the BM circuit.

I can do the divider, but I'm trying to get it all in a small box, so the less parts the better.

thanks again John.

Chuck

[John Lyons]

In the big muff you don't have a dedicated voltage reference.
You have points with a certain voltage but these would be affected if you tapped of them I believe.

For a VRef to work correctly you need to a balanced resistor pair from power and ground and often a cap to ground from the reference junction between them to help with keeping the vref more stable.