Building my first module, would love your advice

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Leisure Cove
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Building my first module, would love your advice

Post by Leisure Cove » Thu Jul 09, 2009 1:13 pm

Despite collecting (for lack of a better term) PCBs from CGS, Fonik and now Thomas White, I have yet to build my first module. Fortunately, I now have some time/a handful of dollars and will be placing a Mouser order this weekend. Let the games begin! :guinness:

With that said, I have some rookie questions about module-building that I was hoping you all could help me answer.

(If there is already a post answering these questions, I apologize for asking them again-- I did not find it.)

Here goes:

I will be building Thomas White's Resonant Low Pass Gate first. I bought two of them, and will be building one with "slow" vactrols (to be more of a filter) and one with "fast" vactrols (to be more of a traditional LPG). The info/BOM/etc. for it can be found here.

My questions are:

1. I'm building these modules to be part of my Euro system. What is the Euro power connector's "part number" name (is it the MTA-100)?

2a. Also, because I'm building on a Euro scale, I'm trying to find the smallest pots out there. I came across these. The lugs do not have holes in them-- I assume they're for soldering directly to the PCB, which I will not be doing. Do any of you have experience with pots of this type, specifically with soldering wires directly to them?

2b. On a related note, do you have any tips on finding blank 3U faceplates? I'm looking around the Mouser site but am coming up short. I'm hoping to find ones that are 12HP wide.

3. I've heard that vactrols can be flaky. That is, 2 out of a batch of 10 might not be up to spec/work, something along those lines. Should I err on the side of caution when ordering them (and order extras)? Have any of you run into a similar situation in the past?

4. Finally, I'm looking for a way to mount the PCBs. I've looked at the mounting brackets that Bridechamber and MFOS sell, but they are both shown alongside larger format systems. Are there smaller options? What do you Euro-format DIYers use?

Thanks in advance for helping me get underway! I'm very excited to get started and look forward to reading any advice you can pass over. :party:

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Re: Building my first module, would love your advice

Post by consumed » Thu Jul 09, 2009 3:12 pm

Leisure Cove wrote: I will be building Thomas White's Resonant Low Pass Gate first. I bought two of them, and will be building one with "slow" vactrols (to be more of a filter) and one with "fast" vactrols (to be more of a traditional LPG). The info/BOM/etc. for it can be found here.

My questions are:

1. I'm building these modules to be part of my Euro system. What is the Euro power connector's "part number" name (is it the MTA-100)?

2a. Also, because I'm building on a Euro scale, I'm trying to find the smallest pots out there. I came across these. The lugs do not have holes in them-- I assume they're for soldering directly to the PCB, which I will not be doing. Do any of you have experience with pots of this type, specifically with soldering wires directly to them?

2b. On a related note, do you have any tips on finding blank 3U faceplates? I'm looking around the Mouser site but am coming up short. I'm hoping to find ones that are 12HP wide.

3. I've heard that vactrols can be flaky. That is, 2 out of a batch of 10 might not be up to spec/work, something along those lines. Should I err on the side of caution when ordering them (and order extras)? Have any of you run into a similar situation in the past?

4. Finally, I'm looking for a way to mount the PCBs. I've looked at the mounting brackets that Bridechamber and MFOS sell, but they are both shown alongside larger format systems. Are there smaller options? What do you Euro-format DIYers use?

Thanks in advance for helping me get underway! I'm very excited to get started and look forward to reading any advice you can pass over. :party:
sweet!

1. you can use double row mta-100 headers.
they typically come in long 6" strips that you just cut down to size.
.100 refers to 0.1" distance between pins
EDIT: i dont see the double row mta .100 headers at mouser? (i picked mine up at frys)


2a. no experience with this pot but it will probably be just fine
you are paying a nice premium to get those pots so small
i use the 16mm alphas which are small enough to fit next to each other
while maintaining the pot spacing i prefer (no closer than 18mm centers)
http://www.smallbearelec.com/Detail.bok?no=555

you can solder directly to those pins on the pcb-mount pots
i would recommend you pick up some of this wire that will make this job a lot easier
http://www.smallbearelec.com/Detail.bok?no=85


2b. someone else here on the forum might have better advice, but
you should check with local machine shops that might cut down 2mm aluminum sheet to your specs
alternatively, you can order precision sized blanks from FPE, but this is a much more expensive option


3. im building up my LPG boards too.
i havent heard that vactrols wont work or are flaky
ive read that matching vactrols can be a bitch because of the variation between them
im not going to worry about it
honestly, i'd welcome two different vactrol responses between modules TBH


4. you can mount your pcbs a few ways

- mount it by the pots (least sturdy, have to be careful when mounting)
- use standoffs that screw into the front panel, and tiny l-brackets on the pcb side
- make your own bracket: go to home depot/lowes and buy 1/16" L-shaped aluminum, 3/4" x 3/4"
aluminum is easy to cut and drill
Last edited by consumed on Thu Jul 09, 2009 6:17 pm, edited 1 time in total.

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Post by vav » Thu Jul 09, 2009 5:19 pm

Holy shit, i'm buying boards once they come back into stock!

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Re: Building my first module, would love your advice

Post by wetterberg » Thu Jul 09, 2009 6:57 pm

consumed wrote:ive read that matching vactrols can be a bitch because of the variation between them
im not going to worry about it
honestly, i'd welcome two different vactrol responses between modules TBH
BUT in a traditional LPG you can at times have one vactrol for the vca, one for the filter, right? Which means that you can have a mismatch on a single module, where the sound might filter out quickly, yet take some time to die out completely, etc. ?

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Re: Building my first module, would love your advice

Post by Roycie Roller » Thu Jul 09, 2009 8:23 pm

Leisure Cove wrote:Despite collecting (for lack of a better term) PCBs from CGS, Fonik and now Thomas White, I have yet to build my first module. Fortunately, I now have some time/a handful of dollars and will be placing a Mouser order this weekend. Let the games begin! :guinness:

With that said, I have some rookie questions about module-building that I was hoping you all could help me answer.

(If there is already a post answering these questions, I apologize for asking them again-- I did not find it.)

Here goes:

I will be building Thomas White's Resonant Low Pass Gate first. I bought two of them, and will be building one with "slow" vactrols (to be more of a filter) and one with "fast" vactrols (to be more of a traditional LPG). The info/BOM/etc. for it can be found here.

My questions are:

1. I'm building these modules to be part of my Euro system. What is the Euro power connector's "part number" name (is it the MTA-100)?

2a. Also, because I'm building on a Euro scale, I'm trying to find the smallest pots out there. I came across these. The lugs do not have holes in them-- I assume they're for soldering directly to the PCB, which I will not be doing. Do any of you have experience with pots of this type, specifically with soldering wires directly to them?

2b. On a related note, do you have any tips on finding blank 3U faceplates? I'm looking around the Mouser site but am coming up short. I'm hoping to find ones that are 12HP wide.

3. I've heard that vactrols can be flaky. That is, 2 out of a batch of 10 might not be up to spec/work, something along those lines. Should I err on the side of caution when ordering them (and order extras)? Have any of you run into a similar situation in the past?

4. Finally, I'm looking for a way to mount the PCBs. I've looked at the mounting brackets that Bridechamber and MFOS sell, but they are both shown alongside larger format systems. Are there smaller options? What do you Euro-format DIYers use?

Thanks in advance for helping me get underway! I'm very excited to get started and look forward to reading any advice you can pass over. :party:
1. the connectors & headers used in Euro are referred to as IDC 16-way. MTA are usually used for MOTM, Blacet, +/-15v DIY, etc.

2a. I 2nd consumer's idea- these pots will be fine, but you will have to keep a steady hand as you solder the wire to the lugs :razz:

2b. What about Doepfer's blanks?

3. Not true. The only problems people have with vactrols are that they vary in response (ie. decay time). It's only a problem if you want 2 LPG's to be exactly the same (IMO, a futile endeavour :deadbanana: ).

4. I've started making my own L brackets out of thin strips of aluminum that i cut from sheets of approximately 0.5mm aluminum. It's quick, and i can shape them any way i need.

Feel free to ask any questions when you're building them! good luck

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Post by Funky40 » Thu Jul 09, 2009 8:24 pm

2. the pot makes no sense in my opinion.
-the usual 16mm alphas are small enough.
placing them closer than possible is IMO to close


I have differences in Vactrols, taking some more is not stupid.
If really an Issue, then the faster the more in my opinion, and vise versa.


You get 12TE blank panels from Reichelt (Fischer), but those are 0.5mm thicker than original euro panels.
Maybe one of the German guys can get some for you.
Or ask anaolue Haven or Bridechamber if they like to stock some.
Also 6TE available.


PSU connectors is also easy to get from Reichelt, no Idea about US numbers.
Reichelt is PS/16 for 16 pole i think.



Mounting PCBs is a problem.
I get thin strps of 1.5mm aluminum, 15mm wide cutted by a friend, and make then my own angles out of them

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Post by DGTom » Thu Jul 09, 2009 11:12 pm

I use those 9mm Alphas in my Lunetta (in my avatar!). They are neat :D makes doing 'Blacet Grid' (6 pots from top to bottom) alot easier & means you can still fit switches, 5mm LEDs 'outside' of the grid.

I've also been soldering them straight onto protoboard which works really well & makes building alot faster.

These panels are VERY dense, good for set & forget applications, not good if you like to get busy tweaking! for modules that I need to have more realtime control I mount the pots with Serge distances between pots.

I didn't know smallbear had those! Way cheaper than I get em locally! Thanks!!

I mount my PCBs in a sorta wierd way I think. But, it works! I use nylon spacers, one is attached to the PCB, this one has a 3mm hole drilled thru the middle, I then screw this into a 2nd nylon spacer, making a T, which is screwed into the front panel. Its easy, quick, lighter than alum. angle but takes a few parts to do - 4 spacer & 6 screws for 1 PCB.

Will try & get pics if anyones interested.

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Re: Building my first module, would love your advice

Post by consumed » Fri Jul 10, 2009 12:24 am

Roycie Roller wrote:1. the connectors & headers used in Euro are
referred to as IDC 16-way. MTA are usually used for MOTM, Blacet, +/-15v DIY, etc.
good catch roycie! i totally forgot that nomenclature
mouser http://mouser.com/catalog/catalogUSD/638/1379.pdf
check the vertical double row .100 x .100)

btw the mta-100 headers can be used for all sorts of great stuff if your pcb has .100 spacing
check out some of fonik's builds to see how he uses mta-100 headers and connectors
ive just started doing this myself and it really is a nice way to assemble
userpix/57_topp281fin3_1.jpg

wetterberg wrote:
consumed wrote:ive read that matching vactrols can be a bitch because of the variation between them
im not going to worry about it
honestly, i'd welcome two different vactrol responses between modules TBH
BUT in a traditional LPG you can at times have one vactrol for the vca, one for the filter, right?
Which means that you can have a mismatch on a single module, where the sound might filter out quickly,
yet take some time to die out completely, etc. ?
maybe yes? honestly i dont know about this.
i have not yet traveled down this road so i dont know what part the two vactrols play, and how they play, with each other

re:bracket...
here's the backside pic of the same module with my 1/16" 3/4" x 3/4" aluminum angle i picked up at lowes
making the bracket usually takes no more than 10-15 minutes
userpix/57_topp281fin2_1.jpg

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Post by Leisure Cove » Fri Jul 10, 2009 7:26 am

This is a ton of help, guys-- THANKS!!

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Re: Building my first module, would love your advice

Post by fonik » Fri Jul 10, 2009 10:56 am

wetterberg wrote:BUT in a traditional LPG you can at times have one vactrol for the vca, one for the filter, right? Which means that you can have a mismatch on a single module, where the sound might filter out quickly, yet take some time to die out completely, etc. ?
same here. thomas whites PCB uses two single vactrol instead of one double vactrol (for my p'n'p layout i used a dual vactrol to save cost and space).
Big Boss at fonitronik.de
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Re: Building my first module, would love your advice

Post by consumed » Fri Jul 10, 2009 11:13 am

fonik wrote:
wetterberg wrote:BUT in a traditional LPG you can at times have one vactrol for the vca, one for the filter, right? Which means that you can have a mismatch on a single module, where the sound might filter out quickly, yet take some time to die out completely, etc. ?
same here. thomas whites PCB uses two single vactrol instead of one double vactrol (for my p'n'p layout i used a dual vactrol to save cost and space).
are you saying that matching vactrols is a necessary step then?
btw are dual vactrols matched already? i didnt even think about this.

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Re: Building my first module, would love your advice

Post by parasitk » Fri Jul 10, 2009 11:21 am

fonik wrote:
wetterberg wrote:BUT in a traditional LPG you can at times have one vactrol for the vca, one for the filter, right? Which means that you can have a mismatch on a single module, where the sound might filter out quickly, yet take some time to die out completely, etc. ?
same here. thomas whites PCB uses two single vactrol instead of one double vactrol (for my p'n'p layout i used a dual vactrol to save cost and space).
However the most recent version of the White PCB can take a dual vactrol:

http://www.naturalrhythmmusic.com/lopass.html
naturalrhythmmusic.com wrote:Ability to use 2 Single or 1 Dual Vactrol (see below)
Image

:tu:

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Post by Hi5 » Fri Jul 10, 2009 11:37 am

for the power connection headers I have been a fan of the following as it has a shroud that makes sure you dont plug it in backwards

You can find both on this page:

http://www.futurlec.com/ConnIDC.shtml

Ribbon cable connector: (keyed to prevent backwards insertion)
http://www.futurlec.com/Connectors/IDCC16pr.shtml

Bus board connector: (keyed to prevent backwards insertion)

http://www.futurlec.com/Connectors/IDCMH16pr.shtml

Ribbon cable:

http://www.futurlec.com/Cable.shtml

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Post by Leisure Cove » Wed Jul 22, 2009 10:45 am

Here's an embarrassing rookie question for a Wednesday:

This part (a 1.0 uF boxed metal film cap) from the Thomas White LPG Bill of Materials is listed as "obsolete" on the Mouser site.

What would be a suitable substitution?

I feel a little :oops: for asking, but I want to get it right.

Thanks!

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Post by consumed » Wed Jul 22, 2009 11:50 am

Leisure Cove wrote:Here's an embarrassing rookie question for a Wednesday:
This part (a 1.0 uF boxed metal film cap) from the Thomas White LPG Bill of Materials is listed as "obsolete" on the Mouser site.
What would be a suitable substitution?
you can probably use many different caps for this, but here is one that is nearly alike:

mouser# 871-B32529C105K189

the only difference i can see is that these have a 10% tolerance instead of 5%.
i got this part# by searching on the description of the obsolete part:

"Boxed Metal Film Capacitors 63V 1.0uf"

...and i made sure the lead spacing was similar (5mm) although this is not really that important since leads can always be bent to fit.

searching for "Metal Film Capacitors 1.0uf", filtering by "stocked", "radial" and "5%" will give you a number of suitable options too.

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Post by Leisure Cove » Wed Jul 22, 2009 12:00 pm

Consumed, you are a scholar and a gentleman. Thanks!

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Post by haricots » Wed Jul 22, 2009 2:52 pm

I just finished my LPG a couple of days ago.

The obsolete capacitor can be replaced with http://ca.mouser.com/Search/ProductDeta ... U%252b4%3d

I mistakenly bought this http://ca.mouser.com/Search/ProductDeta ... 1lAWmmw%3d and had to add legs so that it would fit, but it works fine nonetheless.

As far as vactrol matching goes, I bought 4, threw two in and it sounds nice to my ears. :hihi:

Have a look here as well > http://modularsynthesis.com/nrm/lopass/lopass.htm

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Post by Leisure Cove » Thu Jul 23, 2009 5:50 am

Thanks, Haricots! Very good to know.

Your build-blog looks great. How did the wiring go? Do you have any issues/do you have any photos of that stage of things that you can share?

My Mouser/Allied/Small Bear order was (finally) placed yesterday, and I should be getting down to work on my LPGs next week!! :banana:

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Post by haricots » Thu Jul 23, 2009 8:50 am

That actually isn't my blog. I wish I have found this site while I was building my LPG.

I'm a relative noob to building so I always run into issues. This time I wired all the pots backwards. Lug 1 goes to ground, 2 goes to the appropriate pad, 3 goes to the jack tip lug. I'm still not 100% sure I'ved wired the CV in jack properly but it does work. I have both cv in and control going to the same pad (direct cv in).

If you run into trouble give me a shout at beansharicots(at)gmail.com and I can help or supply pictures. If I can build this thing, anyone can! :)

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Post by Leisure Cove » Thu Jul 23, 2009 9:02 am

haricots wrote: If I can build this thing, anyone can! :)
Right on-- thanks! :tu:

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Post by parasitk » Thu Jul 23, 2009 11:14 am

haricots wrote:Have a look here as well > http://modularsynthesis.com/nrm/lopass/lopass.htm
Yep, I've been using this page as a reference too. :tu:

Cool info in this thread, thanks everyone! :yay:

I should be placing my parts order next week and finally start building two or three of the eight lopass gate boards I have here! :party:

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Post by consumed » Thu Jul 23, 2009 2:19 pm

dave did some mods to the design so just be aware of that if you're using his page as a reference.

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Post by Dave Kendall » Fri Jul 24, 2009 5:31 am

Hi.

I second the guys here who make their own brackets and front panels. FWIW, I got a whole load of euro blanks cut at the local machine shop from 2mm Aluminium. I can't remember exactly, but enough for more than five 3U racks, along with at least 24U worth of 6U high blanks for around £70 ($100US)...

Home-rolled L brackets, using the pot as a mounting work well - in the photo below, the top pot goes through an M8 washer to give it the same stand-off from the front panel as the pots through the L bracket. This way, no mounting bolts are needed through the front panel.......

I used 1.5mm thick aluminium L bracket from the local large hardware store, which come up to around 1 1/2" x 1 1/2".

The PCB pins on the Alpha 16mm pots are bent back by 90 degrees, so they don't stick out. The pots are mounted horizontally, so that when the grub screws of the knob are tightened on the slotted shaft of the pot, they are biting on the "edge" of the slot, and not closing the slot, (which would make for a crap fit) Other guys, I have read, use a small piece of metal wedged in the slot to stop it closing if you're using a grub screw knob.
(hope that makes sense.... it works, anyway..... :) )

Hope this helps, good luck!

cheers,
Dave
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Post by Leisure Cove » Fri Jul 24, 2009 7:49 am

Thanks for the tip, Dave! I've got to find a local shop-- searching around for blank panels is killing me!

To that end, I imagine someone could make some money selling blank panels to the DIY community. I'm just saying. There isn't a one-stop, cross-format shop for blinds and there should be. Please, someone not affected by the current global recession: take this idea and run with it! :bananallama:

In any case, is that the CGS Tube VCA in your photo? I've had my eye on that one for a future project (Quad tube VCA is what I'm thinking)!

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Post by Dave Kendall » Fri Jul 24, 2009 9:44 am

I've got to find a local shop-- searching around for blank panels is killing me!
On a tip from my uncle a few years back, I went into the local industrial estate in my small town, and found a sheet metal works and spoke to the foreman. The first time I did this, they used offcuts, which made it really cheap..... the second time the manager got involved, and it cost a *bit* more, but still worked out at around 1$ - 2$ per panel.... not bad at all...... :)

In any case, is that the CGS Tube VCA in your photo? I've had my eye on that one for a future project (Quad tube VCA is what I'm thinking)!
It is indeed! although it's still waiting for a proper front panel. When you build yours, definitely include a feedback pot as suggested by Ken on the CGS site. You can get some great wavefolding stuff happening, right up to crazy pitch shifting/mangling madness.
I use 3.5mm jacks, and wired the feedback pot as a normalised attenuator (VCA OUT to ATT IN, and ATT OUT to VCA IN 2) That way the attenuator can be used independently if the feedback function isn't needed on that patch.
In order to still have 2 CV ins, I used the CV summing node for the LEVEL pot (you can just about see a 100K resistor going to the middle pot on the photo in the previous post). The two CV IN sockets were wired to the CV in pads on the board.

Originally I was going to not bother with the clean/dirty switch for any future builds, but on second thoughts, for just one switch you get an extra function, and can still use the feedback pot as an attenuator. In the next build, I'm seriously thinking about a normalised CGS64 VCA in place of the feedback pot - it could be used independently, or when fed with a CV, dynamically change the feedback amount. That should sound very cool - waggling the manual feedback pot back and forth, you can get some almost saw-animator like sounds......

Go for a tube VCA or 4 - you won't regret it..... ;)

cheers,
Dave
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