Seppuku Space Fuzz odd sustain debugging/fix

[aelling]

So, I build the layout from the main page and it worked, but it had some weird sustain that would sputter out 8-bit like, and it wouldn't sustain more than 2 secs. And also the unity gain is like 3 o'clock, seems higher than normal.

I decided to have a look at the schematic and found the FSB thread where it got traced from, but there are still some errors in that schematic though, some things didn't get added/fixed. In the pics there we can see the 1N34 germanium diode looks more like a 1N4148, and there is a 22k resistor soldered on the volume pot between lug 1&2. This 22k would make it parallel to the 1M that is already between lug 2 & ground, so when we calculate that it would turn into 21.52k, meaning the 1M that is only on the layout now is too much. I replaced the 1M with a 22k and it sounds just like the original.

The guy who posted the pics also mention both pots are B100K, which could be the problem with the unity gain, don't think I have any to test so I can't be sure yet.

Hope this helps

[aelling]

Also, there are 17 cuts on the board, not 16.

http://tagboardeffects.blogspot.com/2016/02/seppuku-space-fuzz.html

[Marbles]

Thanks, was planning on building it soon. Judging the comments I don't see that many people having a problem with it tbh. Will try both!

[Travis]

Marbles I can’t think of any specific examples right now but there are certainly times when people give a layout a positive report on the main page and then problems are discovered later

I take their words with a grain of salt because sometimes people get a little eager to jump in as the first person to verify when a layout or schematic may not be 100% correct

[Marbles]

Thanks Travis, You're probably right. Have done that myself too. In my defense, that was the Noise Swash, Who knows what it shouldve sounded like haha

[aelling]

Travis wrote

Marbles I can’t think of any specific examples right now but there are certainly times when people give a layout a positive report on the main page and then problems are discovered later

I take their words with a grain of salt because sometimes people get a little eager to jump in as the first person to verify when a layout or schematic may not be 100% correct

@Travis I went over the thread on FSB when this was traced, went through the pictures to re-draw a schematic for this one.



I don't know if mirosol is around anymore but it could be good to maybe get a fixed layout done. You could still use the original layout but fix the errors, flip the 1N5817's to have cathodes go to IC1 pin 2, anode pin 3, swap 1N34a to a 1N4148, swap volume for B100K and solder a 22K between volume lugs 1&2 (or replace the 1M on the board that is wired between lugs 1&2).
https://1.bp.blogspot.com/-IxVJPJaKegk/VvGv3DpIOOI/AAAAAAAAHak/r0E_FZoMPZIk0WBck7WurZkaDq0rIzkQg/s1600/Seppuku-SpaceFuzz.png