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studyman
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guin guin MME calibration

Post by studyman » Mon Mar 19, 2018 2:38 pm

Hie everyone, i 'm calibrating the MME minimoog clone and I've got -2V between TP6 and GROUND, TP4 and ground but i've got the good +10 for TP8 (oscillo 3). I've got the correct -10V at TP1/TP3/TP5/TP7... any idea of the problem please ???? the -2v start at R18 and R63, before, i've got the good +10V...
Thanks

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jdelgoulet
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Re: guin guin MME calibration

Post by jdelgoulet » Fri Mar 23, 2018 4:44 am

studyman wrote:Hie everyone, i 'm calibrating the MME minimoog clone and I've got -2V between TP6 and GROUND, TP4 and ground but i've got the good +10 for TP8 (oscillo 3). I've got the correct -10V at TP1/TP3/TP5/TP7... any idea of the problem please ???? the -2v start at R18 and R63, before, i've got the good +10V...
Thanks
Chances are that you have some bad solder joins on IC21(TP6) and IC19(TP4).
Try re-soldering both. Be careful note to destroy the pad since they are SDM components.
Using your multimeter, do some continuity tesst between the regulator pins (taken on the regulator) and the pad of the components they go to: you will find the guilty join.

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kid303
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Post by kid303 » Fri Mar 23, 2018 5:04 am

@ Broadwave,

When I was refering to the front panel not being the same I thought there were two black switches on the bottom left but I guess I am mistaken.

What functions do those extra pcbs you have in the shot of the base of your synth.

So you made that aluminium box by bending it with a workmate and some angle bar,damn thats impressive.

Hats off to you man, a real stand up job.

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analogdata
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Post by analogdata » Fri Mar 23, 2018 4:14 pm

Trouble.

None of the +10v test points around TP8 are giving anything at all.

ideas?

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jdelgoulet
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Post by jdelgoulet » Fri Mar 23, 2018 5:20 pm

Chance are there is a bad solder join on the SMD regulator : IC23.

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jdelgoulet
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Post by jdelgoulet » Sat Mar 24, 2018 11:19 am

Like mentioned previously for @studyman :
Chances are that you have some bad solder joins on IC23.
Try re-soldering but be careful note to destroy the pad since they are SDM components.
Using your multimeter : do some continuity tests between the regulator pins (taken on the regulator) and the pad of the components they go to: you will find the guilty join.

cyrdun
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Post by cyrdun » Sat Mar 24, 2018 12:25 pm

Hi,
how accurate should the transistor matching be?
I have a 3 3/4 precision multimeter, I get values between transistors like 0.600mV, 0.588mV, etc, do I need a strict matching? Or is some tolerance allowed?
Thanks in advance :)

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jdelgoulet
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Post by jdelgoulet » Sat Mar 24, 2018 2:31 pm

cyrdun wrote:Hi,
how accurate should the transistor matching be?
I have a 3 3/4 precision multimeter, I get values between transistors like 0.600mV, 0.588mV, etc, do I need a strict matching? Or is some tolerance allowed?
Thanks in advance :)
No need for strict matching. According to the Minimoog service manual you must be within 0.002 V (2mV).
So 0.588/0.600 is perfectly fine.

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analogdata
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Post by analogdata » Mon Mar 26, 2018 9:18 am

jdelgoulet wrote:Chance are there is a bad solder join on the SMD regulator : IC23.
thanks!
it was en embarrasingly big solder blob.

cyrdun
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Post by cyrdun » Tue Mar 27, 2018 9:06 am

jdelgoulet wrote:
No need for strict matching. According to the Minimoog service manual you must be within 0.002 V (2mV).
So 0.588/0.600 is perfectly fine.
thanks :)

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Broadwave
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Post by Broadwave » Thu Mar 29, 2018 2:09 am

kid303 wrote:@ Broadwave,

When I was refering to the front panel not being the same I thought there were two black switches on the bottom left but I guess I am mistaken.

What functions do those extra pcbs you have in the shot of the base of your synth.

So you made that aluminium box by bending it with a workmate and some angle bar,damn thats impressive.

Hats off to you man, a real stand up job.
The re-issue Minimoog has a few extra functions that the original doesn't have - An LFO rate pot on the P.Bend/Mod panel, and two routing switches on the main control panel. The pic below shows the comparison.

Two of the PCBs are from the hacked 4 octave MIDI controller (wheel connectors and the key scanner to MIDI function). The PCB on the right is the MIDI to CV converter.

I was concerned about bending aluminium, but it's easier than you think - a bit of brute force can work wonders :hihi:

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seal_cobblr
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Post by seal_cobblr » Sun Apr 01, 2018 1:01 am

Broadwave wrote:Almost there - I've been a bit distracted by the Behringer D, which arrived a while ago. I've just got to build and wire up the remainder of the left panel.

The cabinet needs to be sanded and a few coats of Teak oil applied to complete the job.

I've ordered a bunch of Cut to Size MDF and iron-on Walnut Veneer to build a second cabinet, just to see which looks better (£40, as opposed to the £100 for the White Oak!).

It's been a total PITA, but worth it... I think?

Image

This is incredible! :yay:

Where did you find the measurements for the wood enclosure? Would you mind sharing them?

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Broadwave
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Post by Broadwave » Sun Apr 01, 2018 5:51 am

seal_cobblr wrote: This is incredible! :yay:

Where did you find the measurements for the wood enclosure? Would you mind sharing them?
From YuSynth (link below)... Click the Minimoog D pic, and you'll find the cabinet dimensions PDF under "Goodies"

http://www.yusynth.net/index_en.php?&arg=3

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seal_cobblr
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Post by seal_cobblr » Sun Apr 01, 2018 6:24 am

Great thanks! :guinness:

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seal_cobblr
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Post by seal_cobblr » Sun Apr 01, 2018 8:17 am

So two more questions, and I'm done for now :)

What size is the metal boat and how long is the aluminum front panel (I've read, that it is 7" tall)?

Is it the 26.75" mentioned here? http://www.tauntek.com/Minimoog.htm

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Broadwave
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Post by Broadwave » Mon Apr 02, 2018 2:44 am

seal_cobblr wrote:So two more questions, and I'm done for now :)

What size is the metal boat and how long is the aluminum front panel (I've read, that it is 7" tall)?

Is it the 26.75" mentioned here? http://www.tauntek.com/Minimoog.htm
Yup, the front panel is 7" x 26.75". The boat I've made is 26.5" x 6.25" x 3.25" - I'm not sure if it's the same dimensions as the Minimoog, but it looks about right, and there's plenty of room for the PSU and electronics.

I've now replaced the MME PCB with the Behringer D, and building a second clone with a Walnut veneered cabinet for the MME.

I'm not sure why, but the Behringer is definitely more gutsy (there seems to be more gain into the VCF/VCA, and sounds far closer to a genuine '74 MM). I've thoroughly checked the schematics but I can't find any difference in the signal path in the MME, so I'm not quite sure what's going on - Weird.
Last edited by Broadwave on Wed Apr 04, 2018 4:01 am, edited 1 time in total.

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analogdata
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Post by analogdata » Mon Apr 02, 2018 10:40 am

Measuring the AnalogBoard -4v Test Points I get -3.85v

Ok or what do I adjust?


Edit:
A more worrying note is that I get no sound but noise.
Noise can be turned up and modulated, but nothing else.

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jdelgoulet
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Post by jdelgoulet » Wed Apr 04, 2018 2:52 am

analogdata wrote:Measuring the AnalogBoard -4v Test Points I get -3.85v

Ok or what do I adjust?

Edit:
A more worrying note is that I get no sound but noise.
Noise can be turned up and modulated, but nothing else.
3.85v is ok.
On the analog board check if you have waveforms on the 3 molex headers. Bottom pin of each molex is ground, others are the waveform. This will confirm that VCOs are working fine.

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bagoly
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Post by bagoly » Sun Apr 22, 2018 9:37 am

Hi everyone,

I guess I'm a bit late to the party, but i finally finished my MME boards, took me a very long time since i kept messing up orders..

Anyways, I just fired it up, the VCOs all act like they should, so do the envelopes, Noise and the VCA.

The VCF on the other hand does not respond to CV at all, that means the Cutoff-pot, envelope and external CV don't do anything at all, it doesn't track the pitch either. I can tell that the filter is working, because i can adjust the cutoff by turning the 'Range'-trimpot, so i guess there might be an issue with Q72 or maybe something went wrong on the control board?

It's kinda hard to troubleshoot without a schematic, because you can't really trace the signals on the pcb once everything is installed..

Did anybody experience something similar? Any relevant voltages i should check?

cheers,
robin


EDIT:

Whoops, nevermind, i just swapped Q72 and now everything works as expected! I will start to tune everything tonight but already played around with it and it really does sound great! :banana:
Big thank you to julien for making this project available!
Perfect sound, great features and just the perfect size/layout for a eurorack-minimoog, plus the build-guide is a piece of art! highly recommended!

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Post by Staticcharge » Thu Apr 26, 2018 11:18 am

kid303 wrote:what is the average power consumption of Eurorack modules so I can make a rough guesstimate as to how many modules the RT-65B will power.

Obviously the Mini Module will take up 60hp and that will leave 44hp out of a 104hp case.

If anyone would have an idea (ballpark) of how many modules the RT-65B will power, let me know please. Cheers
Though as previously stated it's a hard calculation to make, my whole main system runs on 4 RT-65B PSU with 4R7 resistors on the 5v rail to reduce heat and noise on the 12+- rails.
Modular Grid is a good way of calculating but don't take it at face value, add 10% and you should be ok. Both of my 6U x 84HP system use 1 RT-65B PSUs and all run quite happy, the mini buss board is quite a good idea I've done the same but mounted it down the side of my cases and run fly buss from there.

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Post by SMonk » Sat Apr 28, 2018 7:45 am

I'm having trouble with my build. Osc 1 works fine, but 2 and 3 only gives a high frequency output, regardless of octave setting and CV input. On osc2 the frequency knob goes from 1530 to 3250hz, on osc3 it has no effect.

Filter tracks fine. Wave shapes look ok. All voltages seem ok.

Any ideas where i should start looking..?

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jdelgoulet
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Post by jdelgoulet » Sat Apr 28, 2018 12:21 pm

SMonk wrote:I'm having trouble with my build. Osc 1 works fine, but 2 and 3 only gives a high frequency output, regardless of octave setting and CV input. On osc2 the frequency knob goes from 1530 to 3250hz, on osc3 it has no effect.

Filter tracks fine. Wave shapes look ok. All voltages seem ok.

Any ideas where i should start looking..?
All voltages seem ok. : did you validate all the points with step 1.6 of the calibration Guide ?


Also, I've got the feeling this might be the UA741s.
On OSC2 is the frequency knob has an effect on the vco frequency but not the octave switch, try replacing IC4 (UA741 , octave switch buffer of VCO-1) and IC8 (UA741 , octave switch buffer of VCO-2). As we know that VCO-1 works it means that IC4 is good. If that works then you have a fake/bad UA741. If that does not work, I would look at the soldering point on the rotary switches and on JP5 (Step 6 on the build guide).
In the mean time, could you post one HR photo of the analog board and one of the back of the control board ?

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SMonk
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Post by SMonk » Sat Apr 28, 2018 2:01 pm

jdelgoulet wrote: All voltages seem ok. : did you validate all the points with step 1.6 of the calibration Guide ?


Also, I've got the feeling this might be the UA741s.
On OSC2 is the frequency knob has an effect on the vco frequency but not the octave switch, try replacing IC4 (UA741 , octave switch buffer of VCO-1) and IC8 (UA741 , octave switch buffer of VCO-2). As we know that VCO-1 works it means that IC4 is good. If that works then you have a fake/bad UA741. If that does not work, I would look at the soldering point on the rotary switches and on JP5 (Step 6 on the build guide).
In the mean time, could you post one HR photo of the analog board and one of the back of the control board ?
Checked all voltages (maybe missed some +-10, there are a lot of them). All checked out.

Tried switching IC4 and IC8, no difference.
Getting signals that seem ok from the octave switches, frequency pots and cv through the connectors to the analog board to the right of ic4, 8 and 14.[/img]

Image
Image

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jdelgoulet
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Post by jdelgoulet » Sun Apr 29, 2018 4:30 am

So, just to be sure :

----- Test 1 -----
#1 : Remove the ICs : 5, 9 , 12, 2, 6 10, 1, 4, 8, 14 and 13.
#2 : Check both +10v and -10v at those IC using :
- +10v pdf
- -10v pdf
#3 : Plug the ICs back
#4 : Recheck +10v and -10v voltages.

----- Test 2 -----
Most of people mistakes when building the MME came from bad soldering joins on the SMD components. I will prepare a pdf file so you can test you soldering join on the LM3046. Will prepare that asap.


In the mean time, could you make some better photos with a good light ('cos , for example, we can barely see the marking on the trimmer).

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SMonk
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Post by SMonk » Mon Apr 30, 2018 4:32 am

jdelgoulet wrote:So, just to be sure :

----- Test 1 -----
#1 : Remove the ICs : 5, 9 , 12, 2, 6 10, 1, 4, 8, 14 and 13.
#2 : Check both +10v and -10v at those IC using :
- +10v pdf
- -10v pdf
#3 : Plug the ICs back
#4 : Recheck +10v and -10v voltages.

----- Test 2 -----
Most of people mistakes when building the MME came from bad soldering joins on the SMD components. I will prepare a pdf file so you can test you soldering join on the LM3046. Will prepare that asap.


In the mean time, could you make some better photos with a good light ('cos , for example, we can barely see the marking on the trimmer).
Removed all 741's, measured voltages, reinstalled, measured again. All voltages ok.
Also reflowed the 3046's.

Better pics:
Image
Image

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