Mu-Tron Octave Divider

[fontoponto]

Build Rating

5.00 star(s)

Based on the fine BYOC schematics I built a Mu-Tron Octave Divider. The only thing that bothered me was the bass being low in volume. In this forum I found the R16/17 mod. Other than that the stock values are just fine (in my opinion).
Because of the squeezed parts one knob is almost touching one toggle switch and the LEDs could be placed further up.
At first I wanted to do a pcb for a BB enclosure then a stacked version in N1/125B but I was encouraged in another forum to just squeeze it in
I knew from the Swarm/Flock that the CMOS IC are always longer than the socket to I kept a small distance to other parts.
The first version was not working correctly because of missing V- supply in the opamps. I hooked them up to GND and used a flying wire afterwards. You can compare everything a thousand times but the one little… The notes especially point that out in „1.“. Wasted time with threads asking for help and reordering etc.
But now it’s finished without flying wired and I like it! Almost double the costs but we don’t do it to to save money, right?

 

[rwl]

Wow! That's a really dense build with all those resistors stood up.

 

[Mentaltossflycoon]

That's awesome!

 

[Gordo]

I've always liked this circuit and easily my favorite octave box. Nicely done!

 

[fontoponto]

Thanks a lot

 

[giovanni]

I love the graphics! Excellent work!

 

[Feral Feline]

I'm blown away you managed to squeeze all that into a 1590N1.
I also like your attitude of building vs monetary concerns.
Switch and LED placement... superb!

 

[fontoponto]

Thanks. I have to admint that it is not that perfect as the traces are not ideal in terms of crosstalk if that's correct.
I can hear the ringer all the time when I use my headphone amplifier. Next time I can turn up the amp I will check there.
Monetary concerns I have multiple projects that need a second revision because I wanted to save money (or they were not available at that time) and created my own pcb with errors...

 

[swelchy]

Jeez that PCB work is freaking sexy…. Look how packed that build is… this is pedal porn at its finest

 

[fontoponto]

During a Kicad update I must have broken some libraries so I tried to fix the project today.
Don't use it directly as it is but it might be usefull to tinker with it.
Inside the zip is another zip containing the gerber files I sent to JLCPCB.
This is the one from before the update so it should be directly usable.
Remove the .txt at the end of the file.

 

[Bricksnbeatles]

During a Kicad update I must have broken some libraries so I tried to fix the project today.
Don't use it directly as it is but it might be usefull to tinker with it.
Inside the zip is another zip containing the gerber files I sent to JLCPCB.
This is the one from before the update so it should be directly usable.
Remove the .txt at the end of the file.

Awesome! Thanks for sharing. Gonna download later and check em out.

 

[fontoponto]

I uploaded the zip again including an interactive bom because the part names are not readable on the pcb.
It's one of the best plugins for Kicad ("Interactive HTML Bom").

 

[Tomi]

Hi, did you get it to work properly at all? There is a mistake in the BYOC schematic - U5A inputs are reversed and R41 should be 100K instead of 180K. I spotted that troubleshooting the circuit and comparing the BYOC schematic with the original. The wiring on their board is OK judging by the pictures in the doc, and the BOM calls for 3 180K resistors, not 4.

Many years ago I made my own pcb for this as the kit was not available at the moment and I have corrected the mistake, but I think the tracking is still spotty. It randomly shifts the pitch and I went over the build many times making sure it's OK and it is. I even got a bunch of NOS 1N34A diodes to see if they were performing better than the germanium diodes I originally put in. Right now I'm getting an old version of CD4013 as I'm suspecting the newer types might not be performing correctly in Octave Divider. I recently spent several hours trying to get a copy of the FB-2 Feedbacker I made to work properly as it was only generating crap when triggered. I ended up swapping the CD4046 chip for another make and now it works perfectly.

Tomi

 

[fontoponto]

Hi Tomi,
yes its working. I could cut the connetions to pin 2 and 3 of U5A as they are on the backside of the pcb but I really don't want to, only if some one tells me that it sounds dramatically different.
R41 is 180K on my pcb.
Only R16/17 is different from the BYOC schematic.