If someone wants the above DIP switch table with the stock Muffin Factory components let me know.
That faceplate screenshot labeled with the individual component ID's works for the stock MF also.
Here is the website by Kit Rae. Considered the Big Muff bible.
http://www.kitrae.net/music/big_muff_guts.html
Scroll down a little bit to where he indicates what components have the most affect on the sound. Three things:
1) The tone stack, which I talked about in post #1.
2) The feedback filter...
There are several Muffin Factory component values that require changing for the Muffin Factory (MF) to better sound like one of the stock Big Muff Pi pedals.
I took screenshots of the different sections of the circuit and I show in red the MF component values. The first value is with the DIP...
Am I correct in stating that the two collector to base resistors (indicated with red arrows) in the Muffin Factory screenshot below are to bias the two germanium transistors? And that their values were selected primarily to bias the two Ge transistors?
Muffin Factory interstage coupling caps......
Options are 100n fixed and 22n switchable so a choice of 100n or 122n.
Seems like a smallish differential?
I'm thinking keeping the 100n fixed and using something like 680n switchable?
Thoughts? Since many of you have much more experience with Big...
Thank you @Feral Feline for that Muffin tone stack data table!
I've seen many posts by you about the MF build. You've been interested for quite some time looks like.
Now is the time to buy the PCB and faceplate since you can get 15% off.
I bought mine about 5 days ago. I don't know if that...
Here is the tone stack with both resistor DIP's closed for 39k on both.
So.....I figure that since I want to build a Big Muff based Muffin Factory, one that will give some classic Muff tones then I will need to re-design some of the switched values. I will post my resulting changes. In time...
Thanks to @FeralFeline I can run some plots of the stock Muffin Factory.
Here is the plot using the fixed (not switched) R and C values:
Not too good. Am I doing this right? Why would the 130K resistors be specified as nonswitched?
Below, I show a screenshot of the stock Muffin Factory tone circuit. In red are the resistive and capacitive values with the DIP switches closed.
Typical BMP tone circuit high and low pass filter values are shown in this table...
Feral has some great observations!
I was quite surprised to see that 110k input resistor. I think I will use a 39k with a 100k in parallel for a choice of 39k or 28k.
I've only recently played around modifying late version Muff's, the most inexpensive ones.
As I am studying the Muffin Factory...
@jcpst, I started this thread......
I have not studied the schematic any further but I will and will post back if I have any more questions.
I have looked into the parts needed and I ordered them morning. I was concerned about which header pins to use to ensure the DIP switches sit nicely...
Wow Feral.....thanks for your time with the detailed reply. Very helpful!
Because the Muffin Factory already has input resistor R2 on a DIP switch I will use it and stay with the spec'd values resulting in 47k or 33k.
Makes the most sense I'm thinking.