Mini-Modules : Minimoog DIY clone on its way.

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Kipling
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Post by Kipling » Tue Feb 27, 2018 4:51 pm

Jop wrote:Hi there,

Want to start soon with this project but have some doubts how to solder the voltage regulators. Besides the pins is it needed to solder the big ground pad to the back of the chip? Any tips how to achieve this without overheating the regulators?

I have found below instructions, does these make sense?

http://coecsl.ece.illinois.edu/segbot/regulators.html

Thanks!
Yes that’ll do it. I personally use a much larger soldering iron bit (6mm) when doing the ground pad so it stores enough heat to complete it quickly and without it sapping all the heat from a slim bit.

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jdelgoulet
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Post by jdelgoulet » Wed Feb 28, 2018 4:20 am

@Jop : At first I would not recommend to solder the ground pad. Do it once you know that all your regulators are perfectly soldered. (Basically when you get the +10v/-10v measurements).

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Post by Jop » Wed Feb 28, 2018 2:45 pm

Thanks gents, great advise :tu:

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veets
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Post by veets » Wed Feb 28, 2018 6:24 pm

jdelgoulet wrote:@Jop : At first I would not recommend to solder the ground pad. Do it once you know that all your regulators are perfectly soldered. (Basically when you get the +10v/-10v measurements).
As Julien may recall, I had a heluva time soldering the ground pins. On my second time building the analog board I let them float. My MME works fine. Here's what the data sheet for the LM2991 says:

Negative Input voltage. Internally connected directly to the device pin 3. The thermal tab must be connected to a copper area on the PCB at the same potential as device pin 3 (IN) to assure thermal performance, or leave the thermal tab floating. Do NOT connect the thermal tab to any potential other than the same potential at device pin 3. Do NOT connect the thermal tab to ground.

I relied on the highlighted section. I'm curious if anyone things this was a big mistake.

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Kipling
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Post by Kipling » Thu Mar 01, 2018 3:19 am

veets wrote:
Negative Input voltage. Internally connected directly to the device pin 3. The thermal tab must be connected to a copper area on the PCB at the same potential as device pin 3 (IN) to assure thermal performance, or leave the thermal tab floating. Do NOT connect the thermal tab to any potential other than the same potential at device pin 3. Do NOT connect the thermal tab to ground.

I relied on the highlighted section. I'm curious if anyone things this was a big mistake.
I think it means electrically floating not mechanically floating. I would at least tack the thermal tab onto the PCB pad for mechanical strength, and better still solder it fully as described so that it transfers heat to the PCB in operation.

"The thermal tab must be connected to a copper area on the PCB at the same potential as device pin 3 (IN) to assure thermal performance"

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jdelgoulet
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Post by jdelgoulet » Thu Mar 01, 2018 3:44 am

Kipling wrote: I think it means electrically floating not mechanically floating. I would at least tack the thermal tab onto the PCB pad for mechanical strength, and better still solder it fully as described so that it transfers heat to the PCB in operation.
On all the MME I built, I did it exactly for that reason (mechanical). I had never put thermal paste.

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Post by bemerritt » Fri Mar 02, 2018 10:45 am

Sorry to post this here, delete it and then post again. Really mean it this time. IF anyone wants a completed module for the price of the parts PM me. It works, just dont even have a euro/cv controller to play with it anymore.

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Kevin Mitchell
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Post by Kevin Mitchell » Mon Mar 05, 2018 4:46 pm

bemerritt wrote:Sorry to post this here, delete it and then post again. Really mean it this time. IF anyone wants a completed module for the price of the parts PM me. It works, just dont even have a euro/cv controller to play with it anymore.
I've built a controller for under $20...

I'd encourage you to put it away even if you're starting to see dollar signs instead of a model D synth. You'll never know when the itch to tinker returns and you might just beat yourself up. I've never had the nerve to sell something I found worth spending money on - to each their own I suppose.

Julien! Any details on an expansion board for those molex headers? I've already asked but I feel it was overlooked.

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Post by Broadwave » Tue Mar 06, 2018 2:10 am

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
Last edited by Broadwave on Thu Mar 08, 2018 8:12 am, edited 1 time in total.

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nickster
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Post by nickster » Tue Mar 06, 2018 12:44 pm

Here is "Zoe"! She is finally in her new case having had a few cosmetic changes and a new power supply. She has some friends to play with now.
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Thanks to Julien once more for such an amazing project. :nana:

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C49 capacitor value on Analog Board

Post by cyrdun » Mon Mar 12, 2018 10:58 am

Hi,
I've just noticed that the C49 capacitor on the Analog Board has a value of 500pF in the building guide, but the link to buy it leads to a 470pF capacitor. I've bought the 470pF one as linked in the list.
What should be the right value?
Thanks in advance! :)

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Kipling
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Post by Kipling » Mon Mar 12, 2018 11:18 am

470pF will suffice which is a standard value. 500pF is ideal but a non-standard value and very rare.

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Post by cyrdun » Mon Mar 12, 2018 11:26 am

thanks Kipling :)

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Kevin Mitchell
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Post by Kevin Mitchell » Tue Mar 13, 2018 5:18 pm

Way behind on building the cabinet but I've been picking at the 1v per octave controller for months now. I think she's just about ready 8-)

[video][/video]

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kid303
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Post by kid303 » Wed Mar 14, 2018 5:07 pm

Hey Broadwave that Synth is looking sweet and I prefered either the linseed oil but liked most the teak oil if that was the farthest right in the pic, it seemed to bring out the grain somewhat.
Ben at resynthesis the panel guy has some rocker switches now and are you going to get a left controller cover from that spanish syntetizadores feller he has them.
There are only 10 switches on the front of the Eurorack main project so what are the other 4 switches functions and how did you implement them.

The panel isnt quite the same as a Minimoog either so it isnt clearly a replacement panel so did you have to pay extra for the custom job.

I say again old chap, a jolly good piece of work old bean, absolutely stunning.

This is just my opinion but I think it would be kind of tacky to do a complete one for one replica so the subtle differences make it a thing of its own in keeping with a Moog which is far more classy I think, then to plaster Minimoog logos on it, bad taste.

Oh god theres, me saying that, I hope you didnt have the logo in your hands and were about to place it on the cabinet. lol :)

:tu:
Last edited by kid303 on Thu Mar 15, 2018 11:40 am, edited 1 time in total.

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jdelgoulet
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Post by jdelgoulet » Thu Mar 15, 2018 11:37 am

The 4 'more' switches are the one used in the MiniMoog mixer section : you can switch on or off OSC1, OSC2, OSC3 and Noise. They do not appear on the MME as there was not enough space on the front panel.

@Kevin : I'm working on another prototype module and want to finish it so that I can group my PCB orders. Also a little Girl arrived back in September :love: so designing and prototyping is a bit slow at the moment :mrgreen:

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kid303
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Post by kid303 » Thu Mar 15, 2018 11:57 am

Ok great thanks for clarifying that for me, I thought perhaps Broadwave had modified the pcb or something. Oh that reminds me.

Hey Broadwave how did you fabricate the metal box part of the synthesizer.

Julien, new project, oooooooooh,

Any sneakers as to what it might be or is it far too early days for that.

How long do you think you will continue to stock the Mini Modules project as I;d hate to miss out but I;ve just decided to build an Yusynth Dotcom Modular first and then I'd like to make a stand alone synthesizer like Broadwave but later after I've got a bit more experience in diy modular building as the project Broadwave has done is fabulous and looks very complicated and something as fine furniture/classic synthesizer has to be done just right and I think Broadwave has nailed it.

Back to the point again and stop waffling of subject.

Please let us know if you are thinking of winding the project down as I'd hate to miss out.

Cheers

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Post by Jarno » Thu Mar 15, 2018 12:21 pm

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
That looks awesome! But why not just use european oak? (you are in the UK right?) that'll save you a bundle, I suppose. Also, there is PDF whith factory glued real wood veneer, expensive stuff, but really nice. You'd still need to do the ends of course.

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Kevin Mitchell
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Post by Kevin Mitchell » Thu Mar 15, 2018 1:49 pm

jdelgoulet wrote:@Kevin : I'm working on another prototype module and want to finish it so that I can group my PCB orders. Also a little Girl arrived back in September :love: so designing and prototyping is a bit slow at the moment :mrgreen:
Congratulations! That's wonderful news.
I give you props for finding time to continue the projects :hail:

Thanks for the update :yay:

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Kipling
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Post by Kipling » Thu Mar 15, 2018 2:07 pm

Congratulations Julien!
kid303 wrote:Hey Broadwave how did you fabricate the metal box part of the synthesizer.
Possibly something like this bad boy. Just bought one myself but didn't realise until I went to collect it that it weighs in at 123kg. Good job I have a strong workbench, and neighbour to help me lift it up there! :omg:
Image

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Broadwave
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Post by Broadwave » Fri Mar 16, 2018 3:13 am

Kipling wrote:Congratulations Julien!
kid303 wrote:Hey Broadwave how did you fabricate the metal box part of the synthesizer.
Possibly something like this bad boy. Just bought one myself but didn't realise until I went to collect it that it weighs in at 123kg. Good job I have a strong workbench, and neighbour to help me lift it up there! :omg:
Nothing so grand as a dedicated folder I'm afraid (I don't have the room) - I just used a B&D Workmate and two pieces of 3mm aluminium angle. You need to score with a Stanley Knife where you want the bend, pop the alu sheet between the alu angle pieces, line up the score mark, tighten up the workbench, and apply quite a bit of force to bend the alu sheet.

It works for basic things, but nothing complicated.

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delayed
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Post by delayed » Fri Mar 16, 2018 6:19 am

Have any images of the box by itself?

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Broadwave
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Post by Broadwave » Sat Mar 17, 2018 4:30 am

kid303 wrote:Hey Broadwave that Synth is looking sweet and I prefered either the linseed oil but liked most the teak oil if that was the farthest right in the pic, it seemed to bring out the grain somewhat.
I went for a Teak Oil finish - Definitely brings out the grain
kid303 wrote:There are only 10 switches on the front of the Eurorack main project so what are the other 4 switches functions and how did you implement them.
I've deliberately modified the MME design to bring it into line with the '74 Minimoog - jdelgoulet is right about the on/off control over the mixer audio sources. I've also ignored sync, and the variable PW circuit - I've re-instated the resistor divider chain to give back the 3 switched square/pulse waves
kid303 wrote:The panel isnt quite the same as a Minimoog either so it isnt clearly a replacement panel so did you have to pay extra for the custom job.
??? - Not quite sure what you mean. The panel is exactly the same as the original MM (but not the recent re-issue, which has the extra LFO and routing switches)
Last edited by Broadwave on Mon Mar 19, 2018 3:11 am, edited 1 time in total.

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Broadwave
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Post by Broadwave » Sat Mar 17, 2018 4:33 am

delayed wrote:Have any images of the box by itself?
Sadly not... Sometimes I'm so involved in getting a job done that I forget to take pics.

This is the closest I've got:

Image

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Broadwave
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Post by Broadwave » Sat Mar 17, 2018 4:40 am

Jarno wrote: That looks awesome! But why not just use european oak?
I originally ordered the wood in Mahogany (Sapele), but due to a stupid mistake I made in the order, White Oak was supplied, so I just made do with what I received. But I'm very happy with the Teak Oil finish.

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