Mutron Micro V (+?) build guide

[Mustachio]

Hey guys I wanted to put together a thread for this Pedal I entered in the Turkey Day Shootout . I'll try to Include everything even the graphics. Photobucket seems to be compressing and resizing my uploads so Ill try to put everything up on dropbox and or google drive.

The pedal Is the Mutron Micro V with the OTA updated to an LM13700 instead of the original CA3080. As well as updating the chip It uses both sides of the LM13700 and seems to have a sweeter sound then using Just one side of the dual OTA.

Here's the Photobucket Layout sorry it was compressed Ill add a link to a PDF at the bottom.



Heres a BOM List

Mutron Micro V Updated Rev1 BOM
______________________________
Resistors

R1-100K
R2-100K
R3-100k
R4-10k
R5-15k
R6-22K
R7-680r
R8-500K
R9-47K
R10-4k7
R11-47K
R12-22K
R13-33K
R14-330r
R15-330r
R16-22K
R17-6k8
______________________________
Capacitors

C1-0.1uf
C2-100pf
C3-47nf
C4-33nf
C5-4.7uf
C6-4.7uf
C7-100uf
C8-100uf
C9-68nf
C10-2.2nf
C11-1.8nf
C12-10uf
C13-2.2nf
______________________________
Diodes

D1-1N4148
D2-1N4148
D3-1N4148
D4-9.1v zener
______________________________
IC's

IC1-LM13700
IC2-JRC4558
______________________________
Transistors

Q1-2n5089 Hfe 104
Q2-2n5089 Hfe 106
Q3-2n5087-2N3906 Hfe 80
______________________________
Mechanical

Range Switch- DPDT high low
Sensitivity- 1m log potentiometer

I did the layout in ExpressPCB because I'm faster with that then DIYLC but I plan on moving to DIYLC soon (Perrow's Curvy Layouts are sweet!)

I plan on doing more with this circuit, Id like to try to add another 1 or 2 LM13700's , I know Rob was talking about adding an Up/Down option to it. I was also thinking about making the Dual opamp a quad and use the extra channels for an FX loop to color the filter some with another pedal.

I'm going to try to draw up a new schematic for this, but I have to tell ya I'm not good at drawing schematics yet.

When I was trying to get both sides of the OTA working together I ran into a lot of issues. Luckily Ronan was kind enough to help me out! The Amp bias input (pins 1 and 16) need to have the correct current/voltage for the OTA to work correctly. The amp bias max at 2ma and perform best between 0.5ma and 1ma. I believe mine was around 0.9ma. In my layout I changed R8 from 1m to 500K to get it working correctly. And it did work and sounds great , But Ronan mentioned to me that It may be better to leave R8 at 1m and cut R10 in half(currently 4.7k maybe sub 2.2K). I haven't had a chance to try it out yet but ill test it on the breadboard asap.

Will add more to this later. Let me know if you need anything for this build. Ill try to include anything people want . And just run with it, if you can change things up and make it better please do. And add it here.

Here's the pdf that should be easier to read and print from.

https://www.dropbox.com/s/xdwnigkav1j1ad0/MutronMicro5BuildDoc.pdf

[deadastronaut]

nice one jim:  i look forward to the updated schematic...

[oldschoolanalog]

Thanks for all the work you did on this. Great job.
Due to the nicely thought out layout this should be an easy one to perf too.
Beautiful!
PS: Could you please point out where all the I/O, V+, pot, switch and gnd connections go? Thanx again.

[GGBB]

Thanks Jim!  I'll be watching this thread closely.

I did the layout in ExpressPCB because I'm faster with that then DIYLC but I plan on moving to DIYLC soon (Perrow's Curvy Layouts are sweet!)

Just a word of caution about DIYLC - I've found that there are some alignment issues when exporting the trace mask to PDF.  Nothing major, but traces and pads often don't line up perfectly - they are off-center by just a bit.  This doesn't affect me since I'm not etching my own boards (perfboard), but if you plan to etch your own board, be aware of this.  I would do some tests first, it may be that this is a non-issue but I don't know since I don't etch.  You could always correct this in Inkscape or something similar, but that would be tedious for anything but the simplest of layouts.  Otherwise DIYLC rocks.

[pakrat]

Thanks for this Jim, I can't wait to build one!

[lonewolf]

I was looking this over and I dont see the 680 ohm R7 that connects the neg side of C6 to pins 2,3 of the 1m pot and D2 on the layout..

[Perrow]

Curvy layout in progress, 1590B-able

[garcho]

Can't wit to build this, thanks bro!

[deadastronaut]

Curvy layout in progress, 1590B-able

goody gumdrops!..

[midwayfair]

If we can get a schematic posted in the thread, I'll be happy to do the perf layout.

No promises on it fitting in a 1590A, though.

[Perrow]

goody gumdrops!..

How's this?

[Mustachio]

Ah Its lookn great Perrow! Love the curves and the compactness. My layout works but is not as compact I was pressed for time just to get it working for the contest.

Sorry I didn't label everything in the overlay. In ExpressPCB I have the labels on another layer. R7 Is right above C2 and D2 just 2 pads nothing representing because of space. the switch is the CA/DB pads .



Gonna be working on the new Schematic asap. Thanks everyone

[armdnrdy]

Hey Perrow,

Looks good! But let me give you some advice from experience.

The traces on the board that aren't connected to anything may look good but can cause issues. I did a "copper pour" on a board I routed in Eagle. The "pour" fills in empty spaces with copper. In other words, it keeps the copper from being etched in those areas which is good for ground planes and to extend the life of your etchant.

Now this is the important part! I did the pour but didn't rename it ground which enabled isolated islands of copper to remain on the board.

This is the really important part! When I populated the board, wired everything up, and turned it on, there was noise all over the place!

I worked at finding the problem for days! Finally, while audio probing the build, I discovered that these isolated bits of copper were acting like an antenna and were picking up signals from the nearest traces!

The fix: I had to jumper all of the islands to ground! Pain in the butt!!!

Lesson learned: Do not leave any copper on the board that is not attached to part of the circuit or ground!

[Perrow]

Haven't had any such problems, but good to know, I'll post a layout without them. It's 1 am here now so it'll have to wait til morning at least.

[armdnrdy]

That's no excuse!!

Get out of bed and do it now!!!

[Perrow]

Mustachio, could you post a sketch on how to hook those switch pads to the switch, i.e. which pad goes to which lug on the switch.

[Mustachio]

Yup Ill draw something up . In the mean time C and A go to the top end of a switch and D and B go to the center lugs.

[] [] C-A
[] [] D-B
[] []

Ill draw something in photoshop later.

[Jdansti]

Great stuff!

BTW, I haven't looked at Photobucket on the desktop, but the mobile app has several upload resolution settings including full resolution.

[Mustachio]

You know I thought they had the options before that allowed full res. But they changed things up on their website and I cant find any options for that yet. I uploaded these from my desktop. Because I had issues with the mobile app before. Gonna look into it more. but in the mean time Ill try to use dropbox and google drive with higher res stuff.

[Jdansti]

That'll work!