About the Buff N Blend circuit

[gutsofgold]

http://aronnelson.com/gallery/main.php/v/Toneys-Album/Buff_n_Blend.png.html

Looking at that vero layout, you have Effect Input and Effect Output connections on the board. Does that mean, the Effect Input connection goes to the INPUT on my effect circuit board (in this case a big muff) Or does Effect Input imply that it wants an input at that connection from the effect circuit (thus it would go from the effect circuit OUTPUT to that connection). Sorry if thats confusing but I am trying to debug my non-working Big Muff with built in blend control here.

[gutsofgold]

the more I think about it, I'm pretty sure I have it connected right.
EFFECT OUTPUT goes to VOLUME POT LUG 2
EFFECT INPUT goes to INPUT ON CIRCUIT BOARD

I'm getting good voltages on the transistors on the big muff board.

On the JFET on the blend board I'm getting:
D - 9 v
S - 5.1 v
G - 4.5v

Does that seem right?

[MikeH]

That's how I interpret it.  Effect "In" and "Out" are the In and Out on the board of the effect you're blending, not the buff n blend circuit.

[gutsofgold]

Hmm, well I built an audio probe and the signal stops short somewhere on the blend circuit. I've tried putting the JFET in both ways didn't change much. by the way does anyone know the pinout of a MPF102?

Could it be that I am using two seperate batteries in this circuit? One for the blend and one for the BMP? Both batteries have their neg terminal going to the RING of the input jack, so essentially both circuits are sharing both grounds. Could this be a problem?

[gutsofgold]

I should have guessed... the JFET was dead! D - E - A - D. The audio probe helped me figure this one out, thank you to whoever came up with that awesome idea.

Now my BMP is a little more 'useable' !