Blender circuit... where to place buffer

[disorder]

I have seen two different single FET blender circuits, one where the input signal splits after the FET and one where it splits before the FET.

Both of these make sense to me but is there any advantages/disadvantages to note between the two configurations? If it matters I am trying to blend the clean signal with big muff output for bass.

[Harry]

I'm curious too... bump

[ashcat_lt]

It's basically about controlling the effective impedance of the load as seen by your source, but it's not exactly simple to answer much beyond that because a lot of different possibilities exist.  If I was actually looking at the circuits in question it would be easier, but there are neither pictures nor links in this thread, so...

[Harry]

Disorder provided two underlined links to the examples in the original post.

[amptramp]

The Big Muff has a fairly low output impedance of around 15 K (roughly the value of the collector resistor in the output stage).  As a result, the blender that splits after the FET is the right choice - the delicate input signal is buffered using a stage with a high input impedance and the blend is driven by its 3300 ohm output impedance.  Points A and B can be shorted and the output impedance of the blender does not exceed 59.15 K.  This is not a particularly low value, but it gets reduced as the blend control moves from this position.  The impedances go up as the frequency goes down, but this is not expected to be a major concern.  Some output capacitor selection may be necessary to prevent the blend percentage from being skewed at low frequencies toward the buffered signal.

[ashcat_lt]

Disorder provided two underlined links to the examples in the original post.

You know you're right?  Don't know how I missed that.  Sorry.

I think I'd probably go with splitting after the FET like amptramp said, but in this case I'm really not sure that it matters much.  If you put the big muff between the Send and Receive of the after scheme, then the guitar won't see its output but rather its input in parallel with the buffer.  That'll be a bit lower than either by itself, but probably still high enough for most folks.