I've always been interested in analog synths, but the costs involved are scary. The full kit for the ASM-2 is something like a grand in AUD from Elby Designs, the PCB alone costs a hundred bucks.
Also, how do people deal with the front panels? The pots and jacks (which, from what I can tell, are almost never PCB mounted, meaning 'orrible amounts of pot wiring.)
Any synth-diy'ers here got any tips?
I think frequency central might be a place to look for some ideas.
Jacob
A website called "Papareil Synth Labs" also has some great resources and kits available.
yusynth.com had PCB designs for a nice set of modules but the site changed somewhat. I have it archived.....
They have a good list of links to various projects here:
http://yusynth.net/index_en.php?&arg=6
Peter
Alan,
the key is starting small. I got started by a friend who was etching a lot of pcb's. also if you figure that at a grand, you are basically getting a synth that would be $2500-$3000 commercially, there you have it. Also, don't get kits. In the US I've found the kit markup to be silly, AND I don't like pcb mounted much so I tend to do my own control layouts and like to pick those parts myself. If you source the parts I think you can save a lot of money.
also bear in mind you only need a few synth modules to do very crazy stuff, so something like the ASM is sort of over the top depending on your desires. do you want to start with just a basic synth? PAIA Fatman is amazing sounding actually. If you want to go modular look at CGS but then source the parts yourself instead of buying parts kits from a 3rd party.
Strategy
Think I might go with the Frequency Central stuff, but do my own faceplates. I'd prefer to go with 6.5mm, not 3.5mm jacks. Plus Rick is a great guy.
Rick's projects will be great. He has pcb's you can buy AND etch your own versions, they are nicely in between "building block" modules as well as having 'bells and whistles'.
I'm getting started in modular, and have bought some of ricks (frequency Central) PCB's and front panels. Can't go wrong for the price!
I wish I didn't just learn about the Fatman...now I feel like I need it.
The Fatman uses V/Hz, not V/octave, so it's not compatible with Moog-type synths...
I always thought the stuff at Music from outer Space looked great. He even has a guitar synth project that looks really cool.
http://www.musicfromouterspace.com
Quote from: alanp on March 04, 2014, 04:47:23 AM
The Fatman uses V/Hz, not V/octave, so it's not compatible with Moog-type synths...
I can't afford Moog stuff anyway, so that's probably fine!
Quote from: jubal81 on March 04, 2014, 05:13:02 AM
I always thought the stuff at Music from outer Space looked great. He even has a guitar synth project that looks really cool.
http://www.musicfromouterspace.com
Didn't someone here build one of these fairly recently?
Quote from: jubal81 on March 04, 2014, 05:13:02 AM
I always thought the stuff at Music from outer Space looked great. He even has a guitar synth project that looks really cool.
http://www.musicfromouterspace.com
This. And I think the prices seem reasonable too.
Quote from: alanp on March 02, 2014, 05:09:48 AM
I've always been interested in analog synths, but the costs involved are scary. The full kit for the ASM-2 is something like a grand in AUD from Elby Designs, the PCB alone costs a hundred bucks.
Also, how do people deal with the front panels? The pots and jacks (which, from what I can tell, are almost never PCB mounted, meaning 'orrible amounts of pot wiring.)
Any synth-diy'ers here got any tips?
Let me know what you end up with cause I may follow your lead if it's not too expensive. I want to start a synth as well.
I've wanted to do some racked modular synth stuff for a while now. The plethora of formats always slows down my enthusiasm when I get ready to do it. It feels like when I make the choice, I'm pretty locked in, so I don't want to get it wrong.
I've also been thinking about moving my guitar effects all to a rack/modular system and controlling them via MIDI. So, I really need to choose a system and get going with it. The MFOS and Frequency Central stuff both look pretty good as does the stuff from PAiA. On the commercial side, I'm always drawn to want to spend huge amounts of money at Doepfer, but the distributer in the US has prices that are way overboard for me.
What's the best path to take for the hardware/format side?
Quote from: RobA on March 05, 2014, 04:31:03 PM
I've wanted to do some racked modular synth stuff for a while now. The plethora of formats always slows down my enthusiasm when I get ready to do it. It feels like when I make the choice, I'm pretty locked in, so I don't want to get it wrong.
I've also been thinking about moving my guitar effects all to a rack/modular system and controlling them via MIDI. So, I really need to choose a system and get going with it. The MFOS and Frequency Central stuff both look pretty good as does the stuff from PAiA. On the commercial side, I'm always drawn to want to spend huge amounts of money at Doepfer, but the distributer in the US has prices that are way overboard for me.
What's the best path to take for the hardware/format side?
Eurorack is undoubtedly the most popular, and widely supported, format.
Thats the one I'm going with for my ongoing synth stuff as pretty much everyone else is using it right now (and for a reason).
if you want to always change around modules, a racked, paneled format is fine. I want my synths to be more self contained so I'm looking at LMB Heeger or Hammond desktop boxes with everything under one hood so to speak. In a way each synth would be like a little standalone synth - but with all the full patch points brought to the panel. I have had for years a Korg MS-20, which is a bit like this (self contained synth with patch points) so maybe that's the inspiration. But also I lack tools and space, and can't be endlessly making panels, etc. So, you can use modular in an 'all in one' sort of way if you want to keep things small.
the down side would be if you want to change modules! I've spent a long time selecting my choices before committing them to enclosure.
Quote from: raulduke on March 05, 2014, 04:41:39 PM
Quote from: RobA on March 05, 2014, 04:31:03 PM
I've wanted to do some racked modular synth stuff for a while now. The plethora of formats always slows down my enthusiasm when I get ready to do it. It feels like when I make the choice, I'm pretty locked in, so I don't want to get it wrong.
I've also been thinking about moving my guitar effects all to a rack/modular system and controlling them via MIDI. So, I really need to choose a system and get going with it. The MFOS and Frequency Central stuff both look pretty good as does the stuff from PAiA. On the commercial side, I'm always drawn to want to spend huge amounts of money at Doepfer, but the distributer in the US has prices that are way overboard for me.
What's the best path to take for the hardware/format side?
Eurorack is undoubtedly the most popular, and widely supported, format.
Thats the one I'm going with for my ongoing synth stuff as pretty much everyone else is using it right now (and for a reason).
I've been doing some looking around today and it certainly looks like there are more modules/sellers using Eurorack. You mention "for a reason." Is there a technical strength for the Eurorack format? I noticed that it does +/-12V and 5V. I'm not sure, but the other formats didn't seem to include the 5V. I'm assuming that this is mainly for CV, but it could be a big benefit for digital stuff too (as long as the power available is high enough).
All I know is that the old Moog stuff takes up a ton of room compared to Eurorack, and the power supply standards for that is +15V, gnd, -15V, and +5v. (about four pins.)
I saw a fancy power connector on a sequencer somewhere (google is your friend... IF you know the right search terms), and it spoke about some kind of "Doepfur power connector". It looked to have 10-12 pins, so I'm scared to ask!
Quote from: RobA on March 05, 2014, 04:31:03 PM
I've been doing some looking around today and it certainly looks like there are more modules/sellers using Eurorack. You mention "for a reason." Is there a technical strength for the Eurorack format? I noticed that it does +/-12V and 5V. I'm not sure, but the other formats didn't seem to include the 5V. I'm assuming that this is mainly for CV, but it could be a big benefit for digital stuff too (as long as the power available is high enough).
I don't think there is any single particular reason (not specifically technical).
I think it is a multitude of things that have made the format front runner IMO:
> Affordability. Getting started with some Doepfer modules and a low cost case is a lot more affordable than the Frac Rack , synthesisers.com stuff etc.
> Format. Mini Jack connections, compact dimensions, documented standards and format (on the Doepfer site) mean you don't have to take up a whole room for the shell/case of the system, and can even go fully DIY if you wish. Everything is well documented (and has also been done many times before by other DIY'ers).
> Popularity. There is no question that Eurorack is now the most popular format that is available. Look at all the 3rd party modules available and you'll see what I mean. There is some ridiculously cool stuff coming out for the format.
The PSU connector itself is nothing fancy. The +15/=15 and +5 (a recent addition) connections are all doubled up on two pins. I think multiple ground connections are used on some other pins. I think they chose that connector simply because it is widely available.
(http://www.doepfer.de/a100_man/a100b_e.gif)
Thanks for all the info. I'm definitely leaning heavily in the direction of the Eurorack format.
Any suggestions on what modules to build (Euro-Rack) for a first synth?
A VCO, Filter, ADSR, what else? Are the Midi to CV kits as well?
A power supply is the obvious one, and a VCO... lost past that.
Quote from: Beedoola on March 07, 2014, 04:39:14 AM
Any suggestions on what modules to build (Euro-Rack) for a first synth?
A VCO, Filter, ADSR, what else? Are the Midi to CV kits as well?
Personally I would buy a case rather than DIY. Go with a Doepfer and you also get the PSU, so you have that bit sorted.
There are no set rules, but for a 'standard' 2 oscillator synth you would
probably need:
- 2 oscillators
- 1 Filter of some sort
- 1 or 2 ADSR's.
- 1 or 2 LFO's.
- 1 or 2 Mult's (patch points to distribute signals. can be passive or active).
- 1 or 2 Attenuators (to attenuate control signals etc.).
- 1 VCA (Voltage controlled amplifier to control amplitude).
- Couple Mixers of some sort (One to mix your oscillator audio signals, other to mix CV signals).
1 Midi to CV converter of some kind (better to buy).
My advice would be to buy some stuff and add to that. I bought an Arturia Microbrute over Christmas. It does the Midi to CV/Gate conversion, and also has an amplifier, filter, LFO etc. that are all easily interfaceable with other Eurorack stuff.
You get a lot of synth for your money.
Also, sign up to MuffWiggler. That is the forum to be on for synth stuff and advice.
Came across this tonight as I was looking for a Tube VCA.
http://www.cgs.synth.net/pcb/index.html (http://www.cgs.synth.net/pcb/index.html)
prices don't seem to bad for his PCBs and hes got tons of goodies on there for modular stuff.
Cody
I've added the two 'panels' I did in Eagle to OSH park for anyone interested.
2 x 4 Mult and 2 x Passive Attenuator
The work fine for me, and should fit to the Euro-Rack format.
Link: http://www.oshpark.com/profiles/SJ-Effects (http://www.oshpark.com/profiles/SJ-Effects)
Yours to order from OSH park if you want them.
(http://uploads.oshpark.com/uploads/project/top_image/b8rLDzg3/i.png)
(http://uploads.oshpark.com/uploads/project/top_image/2tcVGJsP/i.png)
Especially if you got those in 2.0 mm thick PCB, they'd probably be thick enough to withstand some heavy pressure.
Jacob
The attenuator PCB is certainly thick enough to withstand pressure/knob twiddling.
They do the job fine for me and are there if anyone else has a use. I'll be adding them to my rack when it arrives.
Quote from: lincolnic on March 04, 2014, 05:20:50 AM
Quote from: jubal81 on March 04, 2014, 05:13:02 AM
I always thought the stuff at Music from outer Space looked great. He even has a guitar synth project that looks really cool.
http://www.musicfromouterspace.com
Didn't someone here build one of these fairly recently?
Well... yes someone did:)
http://www.madbeanpedals.com/forum/index.php?topic=5730.msg49618#msg49618
...quite a bit of effort. Worth it though... i think :o
cheers
Bengt! Sorry I couldn't remember it was your build! It's still damned impressive. :D
Ordered some Frequency Central boards and faceplates. (PSU, 100M ADSR, VCA, VCO, Kardiogram VCF (I thought the red plexi panel and the red diodes were a neat-o idea), and a Wave Runner LFO.) Raul, I think I'll order some of your multi and attenuator boards when I've got them sorted. They're sized for... 3.5mm and 16mm jacks and pots?
This should be fun :)
Whether I bodge up a enclosure out of customwood, or buy one (and a power buss board from Elby Designs) depends on the money tree, since I also ordered...
... boards for a Klee sequencer. I'm a sick man.
Okay, after some more research, euro-rack synth-diy sounds really, really fun. I'll admit I make pedals chiefly for the fun of the actual construction more than playing them. This modular synth thing could be a deep, deep rabbit hole.
Yep 3.5mm jacks (these are the ones I use: http://www.thonk.co.uk/shop/pj301bm-3-5mm-jack-sockets-x50/ (http://www.thonk.co.uk/shop/pj301bm-3-5mm-jack-sockets-x50/))and 16mm pots.
It's a rabbit hole alright, and one that I am also going down :)
You'll probably need a Midi-CV converter, and you could do a lot worse than getting yourself an Arturia Microbrute.
You get the Midi-CV, and also a whole analogue synth that you can interface with your future euro stuff 8)
I'm using mine as the 'base' to expand with future DIY modules.
Got half my FreqCentral modules built.
(http://i163.photobucket.com/albums/t282/Gutstwohand/sysxvcoadsrback_zpscdb9cdfb.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/sysxvcoadsrback_zpscdb9cdfb.jpg.html)
(http://i163.photobucket.com/albums/t282/Gutstwohand/sysxadsr_zpsb43927b1.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/sysxadsr_zpsb43927b1.jpg.html)
(http://i163.photobucket.com/albums/t282/Gutstwohand/sysxvco_zps0d049855.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/sysxvco_zps0d049855.jpg.html)
Not a single one tested, though. I don't have a Eurorack power supply or case :( I'm going to test the LFO first with the O'scope, then use that for a clock to test the ADSR, and go from there.
Synthtastic. I don't know much about synths but they look cool anyways. So why is frequency central in a mirror image on the faceplate?
Those Frequency Central modules do look nice.
I haven't tried this yet, but my son told me this morning that he saw on a board somewhere that the Lack tables from Ikea are just the right width to use as a 19" rack case. I'm going to get one and some of the cross rails and give it a try. If it works, it's got to be one of the cheapest ways to put together a rack. I've seen those tables on sale for about US $9.
I am watching this thread closely because this is the direction I would lik to go at some point.
R
Quote from: Hangingmonkey on March 31, 2014, 09:40:27 PM
Synthtastic. I don't know much about synths but they look cool anyways. So why is frequency central in a mirror image on the faceplate?
It's to visibly differentiate between his DIY boards and plates, and his commercially built modules, I think.
Quote from: RobA on March 31, 2014, 09:48:19 PM
Those Frequency Central modules do look nice.
I haven't tried this yet, but my son told me this morning that he saw on a board somewhere that the Lack tables from Ikea are just the right width to use as a 19" rack case. I'm going to get one and some of the cross rails and give it a try. If it works, it's got to be one of the cheapest ways to put together a rack. I've seen those tables on sale for about US $9.
This isn't audio hardware, but it confirms that the Lack tables support 19" rack spacing: http://makezine.com/2010/01/22/lackrack-ikea-server-racks-for-livi/
Yeah the lack will fit 19" rack gear.
You will still need some kind of rack to put your Eurorack modules in though.
I bought one of these (TipTop Happy Ending Kit):
(http://cdn3.volusion.com/nqrze.qngsf/v/vspfiles/photos/TipTop-Happy-Ending-Kit-Silver-2.jpg?1342533446)
Works great and you can use it as a desktop system too.
(http://i163.photobucket.com/albums/t282/Gutstwohand/synthfront_zps4dc6b22b.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/synthfront_zps4dc6b22b.jpg.html)
(http://i163.photobucket.com/albums/t282/Gutstwohand/synthback_zps01b0e172.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/synthback_zps01b0e172.jpg.html)
The LFO is waiting on a 7905 regulator, but all the other modules are working :)
Perfed up a MFOS PSU, using the Cioks AC10 for 12VAC. Good fun :D
Looking good! I hope you'll make us a demo when that regulator comes in.
Any reason why all the modules are so far apart? They look lonely. Build them some more friends. ;D
This remembers me of what I had back 20 years ago.
Later I bought a Roland JD 800 to bring back those abilities without the hassle.
Worked great.
Looking good.
Quote from: alanp on March 13, 2014, 04:08:28 AM
... boards for a Klee sequencer. I'm a sick man.
These just shipped. Today. I'm not making this up.
RS, OTOH, have the absolute BEST shipping I've ever seen.
They'll send me an email the night before, telling me it's on the way, and the courier has it in my hot little hands the next morning! I've never EVER seen a parts company deliver this fast!
My little synth rack is coming along nicely.
Need to order some more stuff from Freq Central.
I've also got a couple of production modules I'm saving up for.
I'll post a pick shortly.
Alan; you should SERIOUSLY consider picking up a mirobrute dude.
It will cover a lot of functionality for you (including midi to CV+Gate) and interface really nicely with your other modular kit.
I'll encourage ANY people with ANY thoughts of any synth sounds here to have a go. Rick's boards make it easy.
Got a minimoog VCF board fabbed (using Yves Usson's schematic), and it works, from what I can tell :)
Don't have a faceplate for it, though. Not in 5U, not in Eurorack format, nuthin'.
If someone can make one up for me if I send them a board (that they can have), that'd be good. It uses Tayda parts, except for the 50kC 9mm pot (which I faked with a 100kB and resistors.)
Check out mutable instruments. The shruthi is a great mono synth, pure analog but digitally controlled I built one it sounded great. The also have the Annika poly synth which takes 6 analog voice cards. The cool thing about these is their modular design and that they have different sound cards you can use, you can even diy your own sound card.
Hey Alan,
What about this?
Too much of a beast to start with? I was thinking about this one.
http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=SOUNDLAB_ULTIMATE/page1.html&VPW=2529&VPH=1229
Quote from: peAk on May 13, 2014, 06:06:26 PM
Hey Alan,
What about this?
Too much of a beast to start with? I was thinking about this one.
http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=SOUNDLAB_ULTIMATE/page1.html&VPW=2529&VPH=1229
A club i'm in has built that and it is quite nice.
The main thing that gives me the sh**s about MFOS stuff is the sheer amount of front panel wiring. To get an idea, search the Build section for Bengt's report on his MFOS Sub Commander.
That said, I am tempted. The front panel wiring just scares the crap outta me.
wow....I did check out that build and what a crazy mess with wires. Saw this on MFOS too:
(http://www.musicfromouterspace.com/analogsynth_new/SOUNDLAB_ULTIMATE/builder_pics/Allen_Cox_Ultimate_Build_002.jpg)
Maybe I will try one of the little noise generators first. :o
With all that wiring, I'm pretty sure that is a noise generator...
But seriously - board mounted pots people!
Jacob
I don't normally swear in forums but - f*ck me!!! How the hell do you keep track of that wiring!?
Extremely carefully, would be my guess.
If you want to get started, hook up with Rick Holt at Frequency Central. All his stuff has board mounted pots.
Quote from: peAk on May 14, 2014, 12:15:11 PM
wow....I did check out that build and what a crazy mess with wires. Saw this on MFOS too:
(http://www.musicfromouterspace.com/analogsynth_new/SOUNDLAB_ULTIMATE/builder_pics/Allen_Cox_Ultimate_Build_002.jpg)
Maybe I will try one of the little noise generators first. :o
Looks like my Multiplex Echo Machine ...
One downside to the wiring in these is, the 3 wires that go to a particular pot are not necessarily next to each-other on the PCB :(.
This is crazy! The nerd in me wants to give it a go, but reality is I have no business even considering that.
A smaller scale synth built into more a guitar pedal layout would be more my speed.
Doing it one module at a time (FreqCentral) is hugely more manageable, especially if you have board mounted pots and not the MFOS spaghetti.
Yeah, I think I'll take your word for it. I just need some type of path because I will be starting from scratch.
(http://i163.photobucket.com/albums/t282/Gutstwohand/seqpots_zpse813ed6c.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/seqpots_zpse813ed6c.jpg.html)
Who wants some sequencer? :)
(http://i163.photobucket.com/albums/t282/Gutstwohand/seqgut_zps389b21c3.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/seqgut_zps389b21c3.jpg.html)
It's using the Fonik Baby 10 schematic (fixed reset problem), going to solder the LEDs in when I mount it to the faceplate. (Ordered one from Front Panel Design, too damn pricey to order from them again!)
Selectable 1 to 10 steps, Gate is toggle-able. Clock in, reset in, reset and step have pushbuttons, and CV and Gate out :)
Awesome! Where did you get the pcb for the Fonik? I've been looking for a good sequencer pcb that's fairly reasonably priced.
Sent from my iPad using Tapatalk
Laid it out myself. I'm still not entirely happy, might send in another version where the pots and switches aren't so damn close.
Looks great! If you have any extras, I would be willing to take one off your hands.
Sent from my iPhone using Tapatalk
Well. I got something for laying out a pcb, so I used it to get more PCB's fabbed.
In a few weeks, I should have boards for the yusynth Steiner-Parker VCF, and the EFM CA3046 VCO -- with boardmounted 3.5mm jacks! I only have the one System X vco (and two minimoog VCF's and a Electro-Cardiogram VCF that can all fake being a sine-out vco) at the moment, so in a way this is kinda sad on my part.
So, I was having fun noodling on the synth earlier (this is hugely fun, although it can annoy the rest of the flat pretty badly at times.)
(http://i163.photobucket.com/albums/t282/Gutstwohand/sbasetup_zpsb008b1c3.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/sbasetup_zpsb008b1c3.jpg.html)
But hang on... what the heck is a guitar pedal doing there?!
The clue is in where the other end of the 6.35mm jacks are plugged into
(http://i163.photobucket.com/albums/t282/Gutstwohand/sbaboard_zps53e9a519.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/sbaboard_zps53e9a519.jpg.html)
Cat Girl Synth's Stomp Box Adaptor (CGS60V1), laid out by me for Euro power.
The fact that you've got the signal chain going through stomp boxes introduces noise (it's inevitable, synths run at like 5V peak to peak, stomp boxes are maybe 200mV ?) but it's fun!
If you're wondering, I had the minimoog VCF oscillating (it sounds nicely gritty), tremolo'ing through the LFO controlled VCA into the multiFX (to give the De Profundis delay something to chew on), with the output going into the Electro Cardiogram filter (red panel.) Obviously while titu'ing with settings on both stomp box (turning fx on and off) and titu'ing with synth knobs as well.
Got 9 more boards for this, going to have to order more jacks. (They're Tayda PCB mount ones.)
Dude. Alan. Enough with the teasing. When are you going to record us a demo of all your fun synth toys?
(http://i163.photobucket.com/albums/t282/Gutstwohand/efm3046vco_zps3434058a.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/efm3046vco_zps3434058a.jpg.html)
Who wants a really, really simple VCO? Saw/square out, freq and PWM controls (either CV or keyboard CV (this one has a trimmer to scale it to v/oct.)) The timing cap (the 10n one) could do with adjustment, but other than that I'm happy with this one.
It's Tom Gamble's EFM 3046 VCO. With board mounted jacks and pots, no more wiring for ME!
I'll be interested to hear how this one goes for you. I've been playing with the LM3046 and CA3046 quite a bit and there are two issues with it related to the schematic I found for what I think is this circuit. The first is that pin 13 of the IC is supposed to be attached to the most negative point in the external circuit for stability of the transistors (see note 4 in the "Absolute Maximum Ratings" section of http://www.ti.com/lit/ds/symlink/lm3046.pdf (http://www.ti.com/lit/ds/symlink/lm3046.pdf)). The second is that in testing of bunches of IC's, I found that the second set of transistors 9,10,11 and 6,7,8 aren't well matched on most of them.
I did a circuit that used the LM3046 before I saw the note about the substrate connection on pin 13. It seemed to work fine on two of the prototypes but then on a third it didn't sound right. I don't know for sure that it was the issue though, but it made me suspicious enough that I scraped that version and went to using discrete transistors for that design. It's a distortion circuit though, so using the discrete transistors has a couple of other benefits too and the added effort of matching is worth it. I'm still playing with the LM3046 though and as long as I plant pin 13 to ground or -Vcc and don't use the unmatched pair as a matched pair, the IC has been really good. It could easily be that I misinterpreted the note in the spec sheet too, but I found a warning about it in some notes for an EE lab that was more explicit about the warning.
It doesn't have the flexibility and range of a fancier VCO, but for what it is (ultra-simple) it does what it's supposed to. The substrate pin 13 is connected to -12VDC through a resistor in this circuit.
Quote from: alanp on June 21, 2014, 03:20:18 PM
It doesn't have the flexibility and range of a fancier VCO, but for what it is (ultra-simple) it does what it's supposed to. The substrate pin 13 is connected to -12VDC through a resistor in this circuit.
My interpretation of the note was that the substrate needs to be held at a lower potential than any of the other pins. The warning from the EE class was that you needed to just tie it straight to the lowest voltage rail. What I don't know, and I couldn't find any good info on it, was how strict this requirement really is.
I like simple. I'll have to try this one on the breadboard for sure and do some playing with it. Did you use a tempco for this? If so, where do you get them?
There's a 1K resistor that is supposed to be tempco, but I didn't bother (it means a special order for it), and the layout has it at right angles to the IC.
Oh, yeah, the schematic calls for a J112 fet, and I used a 2n5457. Seem to have got away with it.
I'm thinking of ordering panels from FPD for it -- if I get 10, then it's 20% off.
(http://i163.photobucket.com/albums/t282/Gutstwohand/spvcf_zps4f0435f4.jpg) (http://s163.photobucket.com/user/Gutstwohand/media/spvcf_zps4f0435f4.jpg.html)
Waiting on caps from chrome, and switches from china, but they look so cool even not working :D
You are building up quite a collection. How big is your rack now? I'm trying to come up with a way to do this in a smaller desktop kinda format. I'm not too successful so far. I did see a commercial synth online that was using breadboard style jumper wires as a patch system, that might be a good step towards miniaturization. Still, it's got to be way more fun to have the wall of full size switches and knobs to play with.
Found some ceramic 1n5 caps, and the steinerparker VCF boards are now verified (only bug is that the resonance control is backwards... always something, but this is fixable with a cut trace and wire :) )
So another Front Panel Express order is underway. I'm a sick, sick man.
But.
This is a major but.
If I've designed this right, then these modules (EFM 3046 VCO, and YuSynth Steiner Parker VCF) will not need ANY wiring done, just mount the populated boards on the front panels :D hell yeah!
I like the sound of that! No wires, thank you, thank you, thank you.
I am busy converting a pair of Neve modules that involve 3 deck/23 way Elma switches, nearly drove me dilly....
'Scuse the cross posting.
http://groupdiy.com/index.php?topic=56638.0;topicseen
Peter
Random ramblings... seemed the best thread.
I might have a go at populating another phase engine board from my Heavy Water Prophecysound Infinitphase board sets, and seeing how well it will work shoe-horned in as a synth module (LFO to be patched in, not on-board.) It does run on +/- 15V, after all :)
'nother random ramble, getting a couple boards fabbed. Mix of Ken Stone's CGS60 Stomp Box Adaptor, plus Harry Bissell's Low Ripple Fast Response Envelope Filter, plus Yusynth's Comparator to provide Gate and Trigger as well as envelope CV.
I really hope it works.