Mini-muffin does not match build docs

[allsmoke]

I just received a batch of 4 mini-muffin fuzz boards, and the build docs do not match. There are 8 resistors on the board, build doc has 7. The diodes are in a different place on the board (not a big deal, but just to highlight the difference).

Do I build to the screen print on the board, or do I build to the schematic/build docs on the site and leave empty spaces (or jumper them)?

Cheers all

 

[DGWVI]

Build to the screen print.


But, I'm curious to see a pic of your board. I've got some on hand and they match the doc

 

[allsmoke]

Build to the screen print.


But, I'm curious to see a pic of your board. I've got some on hand and they match the doc

Here you go. You can see the layout is different and there are 8 resistors, there's no 1k resistor (there is in the build doc), there's 2 100k resistors (none in the build doc)

 

[DGWVI]

Hard to be certain from the pic, but it looks like the 1k in the build doc was increased to 100k (some schematics for the Muff Fuzz online have this value), and looks like the other 100k has been added between pins 6&7 of the opamp.

Build it to the screen print, though. And let us know how you like it.

Maybe @Robert can go over the Revisions with us

 

[Robert]

Do I build to the screen print on the board, or do I build to the schematic/build docs on the site and leave empty spaces (or jumper them)?

My apologies! I've updated the build doc. You have the most recent version. Built it according to the screen print (or updated doc).

Maybe @Robert can go over the Revisions with us

You have the first version. I was based on the schematic that has been around for years.

I believe it was @Guardians of the analog who pointed out that at least some of them used a different circuit, which is what the current version is based on.

I'm not completely sure if there actually are multiple versions, or if the old schematic was just incorrect/ the product of guesswork, but the current version behaves much more as you'd expect (and makes more sense electrically).

You can bump the 1K up to 100K and tack a 100K across the germanium diode pair, or I could send you an updated PCB.

 

[Guardians of the analog]

I believe it was @Guardians of the analog who pointed out that at least some of them used a different circuit, which is what the current version is based on.

I'm not completely sure if there actually are multiple versions, or if the old schematic was just incorrect/ the product of guesswork, but the current version behaves much more as you'd expect (and makes more sense electrically).

When I built the old version that had the common schematic going around the net, I knew it didn't sound like it should. I took a deep dive on the circuit and found a thread with Mark Hammer on diysb (don't quote me on what forum) where he talked about the resistor wissing on the opamp amongst other issues with the schematic on the OG opamp version. The transistor based one is different all together as well. TWS did all that work though, and GotA doesn't have that info anymore