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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Sun Oct 23, 2016 7:00 pm Post subject:
Andy's Yusynth build |
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Hey there!
It's been two years since I last visited, life has been busy throwing stuff at me, keeping me away from my modular. But lately things have changed and I have more time than ever to spend on the build - in fact, it's grown into something even greater than just a synth build...
First a quick recap: I started back in 2012 with an idea to build a standalone Steiner filter, with no clue what to do or how to even begin. I knew how to hold a soldering iron, but not much more. Eventually I managed to build a working filter, but I had no way of interfacing it to my DAW, and so it ended up on a shelf, unused. Life happened and time passed...
Fast forward two years, in August 2014 I decided to build an ADSR to hook up to my filter, but soon I wanted more. I started sourcing components for an entire set of modules - VCOs, filters, envelopes, LFOs, the works. I built a UV exposure box to make proper PCBs, found myself an old oscilloscope and got to work. I managed to etch and populate a few PCBs, but making good looking panels still presented issues that I didn't quite solve.
Then life happened again, and work kept me from the build for a while, then I got very ill for a long time and the modular ended up in the back of my mind. Always what I wanted to do, but never found the time.
Then, this summer, I started streaming games on Twitch, but wanted to try a creative stream. I had wanted to get back to the modular build for a while, and it seemed like a great project to stream. So a few weeks ago, I started a weekly segment on my channel called Tinker Tuesday, where I plan to be making things - and my modular is the main project of the stream right now.
Apart from the Yusynth modules and a few MFOS parts, I'm also designing and building my own modules. Right now, a MIDI-CV interface and a digital wavetable oscillator, both based on Atmel microcontrollers.
I'd like to throw a huge thank you out there to Yves - working on this project and using his excellent designs I've been able to learn a great deal about electronics and designing my own circuits. If I hadn't come across the Yusynth website, quite by accident I should add, on that fateful day in 2012 I might never have bothered to learn about all this. I'm absolutely in love with circuits and electronics now, and I find it such a pleasure to both build other people's designs as well a my own. I'm still a noob, but I'm learning so much and it's opened up a whole new world for me!
So what's my modular look like now? Sadly, not much to see yet. I've just finished my 2nd module - I now have an ADSR and an LFO. Next up is a couple VCOs, VCAs and filters. The old Steiner filter I built has been torn down and components recycled - I'm building a new one following the updated 2.0 design. I have a 22U cabinet almost ready, but it's going to get filled up way too fast so I'm now looking at building a 44U one to go with the first.
If you want, you can check out my progress on twitch.tv/andynatory on Tuesdays from noon CET, and I'll try to post here from time to time.
Cheers!
--Andy |
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micromusic
Joined: May 05, 2014 Posts: 61 Location: england
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Fri Oct 28, 2016 8:11 am Post subject:
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micromusic; those panels look great! nicely done sir!
I've got a few pics to show you; I finished my first VCO yesterday and it works a treat, except no pulse for some reason; I think I saw a thread on that somewhere so I'll be searching around and doing some troubleshooting this weekend. But it seems the LM394's I found cheap on eBay worked after all, I was half expecting them to be fake.
The way I build my panels finally ended up as printed (I'm using Yves' original designs) on regular 200g/m2 inkjet paper glued onto chipboard, then coated with acrylic varnish. It's not perfect, but it's good enough for me, and every batch looks better than the last so I'm getting better. Most importantly, it's very cheap! I reckon each panel costs me less than a euro altogether, and with the amount of modules I have planned on my very limited budget, it's the best option.
Here are a couple of photos for you guys! I've ordered black screws to replace the ones holding the PCBs in place, so they will stand out a lot less eventually.
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MIDI-CV interface prototype board! |
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Modified MFOS bipolar wall wart supply with added +5V rail. |
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First three finished modules (mostly) complete! |
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Skrog Productions
Joined: Jan 07, 2009 Posts: 1196 Location: Scottish Borders
Audio files: 155
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Fri Oct 28, 2016 2:42 pm Post subject:
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So I was looking at the output from my VCO this evening and noticed the Vpp is pretty low, about 6Vpp on saw/tri, and ~4Vpp on sine/pulse. I should be getting 10/8Vpp according to Yusynth.net.
Looking at my board I've noticed that I put a 100K resistor in for R23, which as stated in the BOM "may need to be replaced by a 82K resistor". The layout (colour image) shows a 100K there, but the "component layout" (the PCB silkscreen mask) shows an 82K.
I've found a couple of these discrepancies between BOM, layout, silkmask and schematic. I went with making my board look exactly as it does in the colour image, but I'm now assuming there are errors in that picture and I'm not sure which is more correct - but my guess would be "if in doubt, use the schematic".
Anyway, I'll replace the 100K with 82K and will look for other likely culprits.
If anyone has a hint or idea of what's wrong, don't be a stranger.
For reference, here's the images I'm referring to. I've built the LM394 version of the VCO:
Another such discrepancy I just realized: For R7 the BOM says 1% but it's depicted as 5% in the image. I used a 5% in my build. |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Fri Oct 28, 2016 3:02 pm Post subject:
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Quick update to say I replaced the 100K with 82K and the output popped right up to 9Vpp, still slightly low but I suspect my power supply might be under-delivering somewhat and thus making the on-board regulators drop a bit too much voltage. I'm reading 13.25V off the 78L15 and -13.88V off the 79L15.
I also have a bias on the sine; L3/L4 trimmed for correct saw and tri, and symmetric sinewave, the sinewave lies between +2V/-4V, so it's 6Vpp with a -1V bias.
I'm going to get my bench PSU set up, my modified MFOS wall wart PSU might not be cutting it.
Onwards and upwards! |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Fri Oct 28, 2016 3:43 pm Post subject:
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drakfluga wrote: | I'm reading 13.25V off the 78L15 and -13.88V off the 79L15. |
That's ok in this case (although 13.25 does seem a bit low). The voltage regulators are just there to stabilize and isolate
the supply but because they are fed with 15V the output voltage will be lower. To quote Yves himself:
Quote: | The aim of using these regulators is not to provide +15V and -15V as one would think first. As a matter of fact, because of the lack of voltage overhead and the low current draw they will rather deliver something like 14.2V and -14.2V. This is not a design error but was done on purpose : they are here to isolate the power supply circuit of the VCO core from the general power supply while providing a reference voltage of +/-14.2V. This helps very much in increasing the stability of the VCO.
As such, all the circuit of the VCO core was designed considering the voltage drop through the regulators, and it is a very important point. As such, if one would like to remove/bypass these regulators, one would need to recalculate many resistor values of the VCO core to have it working as expected.
In conclusion, they are there for a good reason |
on a side note, I didn't see any heatsinks on your PSU which I would recommend. _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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gdavis
Joined: Feb 27, 2013 Posts: 359 Location: San Diego
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Posted: Fri Oct 28, 2016 4:22 pm Post subject:
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R7 isnt' critical, 5% is fine.
I wouldn't worry about the output being low by 1V P-P. Should still be strong enough to drive whatever you need and you won't even hear the difference.
If the power supply output is low, I'd just make sure you're not drawing too much current from it (which as PHOBoS mentioned is related to heat sinking). Other than that the difference isn't enough to be concerned about IMO as long as it's good and stable.
There has been some discussion here before about the regulators and the consensus as I recall is that they may be a little lower than the 14.2V mentioned, with one a little lower than the other. I can't remember off hand what the ballpark was, but as PHOBoS mentioned, you might be a little low.
For the sine wave, just get it trimmed best you can. Small discrepancies aren't anything to be concerned about. This is analog, if you want it perfect, go digital If you're still concerned about the sine output bias, matching D5 and D6 should help, but VCO outputs usually end up being AC coupled anyway which removes the bias.
edit: found the thread I was thinking of that discussed the regulator voltages:
http://electro-music.com/forum/topic-54822-0.html&postdays=0&postorder=asc&highlight=
About 13.6V and -14.2V seems normal, so you're a tad low but shouldn't cause any significant issues. _________________ My synth build blog: http://gndsynth.blogspot.com/ |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Fri Oct 28, 2016 5:13 pm Post subject:
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Hey PHOBoS and gdavis, thanks for input and tips!
Photo of the PSU was taken before I put heatsinks on, rest assured there are sinks mounted with thermal compound for extra efficiency. I'm not hugely enthusiastic about the linear regulators and I would like a more powerful PSU in future, but haven't had time to look into it yet. I do hear complaints that switched supplies are noisy, so I'm not sure what's best really. Any input is appreciated.
I started building the VCO two years ago, and can't remember if I matched D5/D6 but I'm pretty sure I would have.. I'm building another VCO shortly so I'll take extra care with that one, the first one was a good learning experience so I'm expecting the second to work out even better.
Glad to hear the readings are normal, perhaps I shouldn't be so worried about my PSU after all. I need to get myself a proper amp-meter to keep an eye on the draw on the rails; the regs do get quite hot already with only the VCO and my MIDI-CV interface hooked up. I can probably do a lot with the latter to cut down power consumption though, it's still in prototype stage.
Speaking of that MIDI-CV interface; finally, I set about adjusting the tracking on the VCO and I'm happy to report it tracks beautifully across at least 5 octaves! I'm also extremely happy that my interface works as intended and the CV out is very linear across 0-10V. Haven't been able to test it properly before as I haven't had a VCO to test it with.
Going to bed very satisfied with today's progress, just feels like I'm making strides almost every day now. Happy days! |
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gdavis
Joined: Feb 27, 2013 Posts: 359 Location: San Diego
Audio files: 1
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Posted: Fri Oct 28, 2016 8:02 pm Post subject:
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drakfluga wrote: | ...the regs do get quite hot already with only the VCO and my MIDI-CV interface hooked up... |
Sorry to spoil your happy days, but this doesn't sound good.
I'm powering two VCO's, a VCF, VCA, two ADSR's and some additional control circuitry all off an LM7815/LM7915 pair and they don't even get warm. All this is drawing less than 200mA on each rail. I didn't even bother with heat sinks. IIRC, the VCO only uses about 30mA.
Something is wrong if your regs are getting hot with just a VCO and MIDI-CV. _________________ My synth build blog: http://gndsynth.blogspot.com/ |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Fri Oct 28, 2016 11:58 pm Post subject:
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My last build which includes a lot of modules (4xVCO,3xLPG,and is consuming 600mA on the positive rail and 100 or 150 less on the negative, the regulators get hot so that you can touch the heatsink just for a minute before you have the feeling it get's to hot...
But it runs stable...
The problem with your PSU if i read the issue of electro notes for PSU's correctly and got all the tips here in the forum right, could be too much input in the regulators... to high AC voltage output from your transformer or maybe too much capacity of the elctrolytes before the regulators.
Also it's normal that the negative reguators mostly have higher outpt voltages than the positives, at least that's in all my builds. Regarding the data sheets for the regulators there is also a bigger tolerance within the output voltages of the regulators too... Could be in the range of more than 1V, from 14,25V up to 15,75V with some load...
Also as gdavis said it could be that you're drawing too much current because of some failure within your modules... how much current is ti on both rails?
Concerning the voltage after your regulators on the VCO i would suggest you if there are no shorts that you use ferrite beads instead of those 10-22R resistors. These cause some voltage drops in the range of 10 to 30mV (?don't remember exactly) where with the ferrite beads this is significant less... Even some smaller resistors could be fine... _________________ https://soundcloud.com/bastian-j |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Sat Oct 29, 2016 3:46 am Post subject:
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gdavis wrote: |
Something is wrong if your regs are getting hot with just a VCO and MIDI-CV. |
wackelpeter wrote: | My last build which includes a lot of modules (4xVCO,3xLPG,and is consuming 600mA on the positive rail and 100 or 150 less on the negative, the regulators get hot so that you can touch the heatsink just for a minute before you have the feeling it get's to hot...
But it runs stable...
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Thanks a lot for the input guys! I'm looking at my PSU now, quite convinced there's something wrong, but haven't been able to locate any fault yet. I'm reading +/- 27.5V after rectification where it should be about +/- 18V. :S
Will keep you posted! |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Sat Oct 29, 2016 4:19 am Post subject:
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It seems I've noobed out. I figured the 18VAC printed on my wall wart was the peak value but in fact it's RMS, so my PSU was effectively feeding my regulators with 25.4V (my multimeter reads 27V but I'm starting to wonder if I can trust that thing anyway, I need a better one...).
I've replaced it with a 15VAC wall wart which should hopefully improve things a bit. With the VCO and LFO1 hooked up I'm still reading ~21V using my scope (which is apparently much more accurate than my multi even though it's early 80's tech ), hooking up the multi in series to measure amps is a bit of a hassle at the moment, so I can't say what the current draw is, but the regulators seem a lot cooler than before at least.
Onwards and upwards! |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Sat Oct 29, 2016 5:51 am Post subject:
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Also have a 18VAC wallwart in my PSU... reducing the size of caps on the input of the regulator can improve things... at least your regulator should get 17V and it should ran stable with some load attached...
maybe just try again with only 2 of these 3300uF caps on each rail... only one maybe could be enough to get at least 17V on the input and as the 17V is the bottom voltage range the regulator needs it's not always running under the highest input voltage and this should improve the heat production a bit...
there was useful calculation in that electronotes issue i mentioned... it was one of the free issues you can still regulary download.
p.s. also take notice if you didn't thought or know of it yet, that on the negative regulator the flat side isn't connected to ground as on the positive regulator, as it's (i don't remember correctly, but i'm too lazy to google, so i write those line, which will probably last longer than a google search ) the input or output of the regulator... but i guess you still knew and where aware of that _________________ https://soundcloud.com/bastian-j |
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
Audio files: 23
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Posted: Mon Oct 31, 2016 6:55 am Post subject:
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the magic factor is 0,707 (you can find this factor also on the -3dB point of a filter, so for me its quite magic
--> 27V*0.707 = 19.089V
or the other way round
--> 15V * 1.414 = 21.22V
the Voltage drop of the diode is not included here
concerning the heat:
if u draw 100mA out, the regulator has to burn
@27V (27V-15V)*0.1A = 1.2W
@21V (21V-15V)*0.1A = 0.6W
cheers, bb
gabbagabi |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
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Posted: Mon Oct 31, 2016 8:37 am Post subject:
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he explained the same thing, but of course better.
if there is no heatsink reachable u can mount the regulator laying down on the board, so the board acts as a less effective heatsink |
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micromusic
Joined: May 05, 2014 Posts: 61 Location: england
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Posted: Tue Nov 01, 2016 3:40 pm Post subject:
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Hi
I use the Digisound PSU
Simple to make and mine will power 40 modules according to Digisound
with my 25 odd modules its not pulling more than 1/2 an amp and with some large heatsinks only gets warm and is nice and stable. |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Mon Feb 13, 2017 5:18 pm Post subject:
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Hey hey!
Sorry about the lack of response, I dropped off the grid for a while there, but I'm back on the build and it's actually taking shape very, very well!
Regarding the PSU, I'm currently looking at building something akin to the Digisound PSU; I've ordered parts, including a nice 50VA toroidal transformer that should provide plenty of oomph! I'll keep you posted on that.
As for the synth itself, I've finished 5 modules - a VCO, Steiner VCF, ADSR, VCA and an LFO. They all work amazingly well! I've just cooked up the PCBs and made the panels for my 2nd batch of modules which will include another two VCO's, mixers, another ADSR, VCA and LFO, the Haible Wavefolder, a Saw Animator and Noise/S&H! On top of that I've also ordered the parts and fashioned a panel for an MFOS 16-step sequencer, the Thomas White rotary variant. It looks like a beast of a build but it'll be amazing when it's done!
So as you can tell, I'm looking at a busy couple of months ahead! I'm also going to continue working on my MIDI/CV-interface. I'm fairly convinced that the heavy PSU draw is due to some error in my design but I haven't had the time to look more closely at it. I will be digging into it again in the near future.
I've already outgrown one 22U cab with what I'm currently building, so I'm going to be building another bigger one based on Yves' 66U design, probably during spring/summer.
Finally, I just have to say... OH MY GOD this machine sounds fantastic! I've not gotten to play too much with it yet, like I said it's only 5 modules but at least I've been able to fiddle around, making little filter sweeps and sequences with what little I have.
I can't thank Yves enough for putting all of this amazing knowledge out there, I am totally, completely in love with synth-DIY now and this project has already paid off more than I ever could imagine in terms of pure joy and satisfaction. <3
Here's a picture of the entire thing I took the other day while test-fitting newly made panels:
https://www.instagram.com/p/BQa1L1jgCBo/ |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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AlanP
Joined: Mar 11, 2014 Posts: 746 Location: New Zealand
Audio files: 41
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Posted: Mon Feb 13, 2017 9:40 pm Post subject:
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It's addictive, for sure
I like your panels! I'm too lazy to make mine myself.
For the power in my next case, I've decided to be lazy and try a SMPS. Other people seem to get away with it. |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Thu Feb 23, 2017 6:12 am Post subject:
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Some things have happened!
I designed, etched and built a PSU based around an LM317/LM337-pair for +/-15V plus another LM317 for +5V for digital equipment. It's currently powered by that 50VA toroid I mentioned, but I might go to a higher capacity/voltage xformer depending on tests with more modules. Currently with 6 modules hooked up the draw is something like 80mA on the +15V rail, so I'm not worried about power consumption at this point.
I also constructed a small power distribution strip which I mounted in the back of the cabinet, it's made it a lot easier for me to power lots of modules, so from now on I won't have to make more and bigger Y-cables every time I finish a module. Very happy with that! It will make it a lot more fun because I can just hook up the modules right away as I finish them. Previously hooking new modules up was quite a hassle.
I captured a quick video of the modular in action. There's not much yet, but it makes fantastic noises. The filter is really gritty and aggressive and I'm totally in love with it!
https://www.instagram.com/p/BQ2rdNhD4Cu
Next up on the todo list is another VCO, some utility modules, VCAs and ADSRs, and I'll also be ordering PCBs for the MFOS sequencer very soon.
Bravely soldering on! [/url] |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Sat Feb 25, 2017 6:53 am Post subject:
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I have a question/pondering/problem. It might seem silly to some, but here goes...
I've built almost an entire cab of YuSynth modules. I've got "a thing" (read: heavy OCD) against mixing and matching modules from different makers within the same cab, so I'd like to keep this cab YuSynth-only and then maybe do a MFOS-only cab, etc.
The problem is, I need multiples, and Yves doesn't seem to have made a design for that.
So, my question: do you think it would be in any way disrespectful/wrong/presumptuous to actually design my own multiples panel (passive using switched inputs for cascading to begin with; I might also make an active buffered multiple at some point) and put the YuSynth logo on it (for OCD reasons, and very much a one-off for my own personal use, obviously I wouldn't dream of publishing it!)?
Or should I find some other existing design and build that, and put it in another cab by itself? I don't like putting an anonymous panel in there, I kinda want a brand name on it or it will feel out of place. Or I might have to come up with my own brand name to put on my own modules, I guess...
Like I said, this might seem totally idiotic to some people but I'm really very averse to putting something that doesn't have "YuSynth" written on it in this cab. I'd love some input, hopefully I'm not the only builder with a terrible case of OCD.
And if you think I'm not making any sense at all, just ignore this rant and forgive me.
Cheers! |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Mar 12, 2017 12:49 pm Post subject:
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You may use the yusynth logo since it is for your own although it is not actually my design _________________ Yves |
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drakfluga
Joined: May 09, 2012 Posts: 49 Location: Gothenburg SE
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Posted: Tue Feb 13, 2018 5:23 am Post subject:
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Right, back in action again, still building my modular! I've had a busy year so I haven't had much time for DIY, but I just started to find my motivation again over the past few weeks and actually made a lot of progress!
Thank you Yves! In the end I chose not to do what I asked though, as I felt it wouldn't be proper or respectful. I actually ended up designing my own buffered multiple, keeping to the style of YuSynth but putting my own logo on the panel. It works very well and gives me three sets of triplets, and switched jacks for optionally 1x9, or 2x6 + 1x3.
I've also made some good progress on my MIDI-CV interface. I mocked up a prototype panel and got everything hooked up, and it works beautifully!
I've built 3 VCO's thus far, two of them are absolutely pitch-perfect and tracking is extremely good. The third one, though, behaves very strangely. I can get tracking across one octave, but if I tune it up to 2 octaves, the first octave up goes flat. For every octave I tune, the lower ones get more and more out of tune. It seems like the curve on the exp converter isn't perfectly exponential, or the linear input isn't perfectly linear, but I can't work out why.
I've tried substituting different components, gone over traces and soldering several times but nothing seems to fix it. At this point, I'm considering simply etching a new PCB, salvaging the valuables from the wonky one.
I've been planning to build a second cab for a while, and I've been looking at Yves' 3-row design, but might abandon that for another single-row just like I have already. Simply because it's easier and I am quite concerned about saving space at the moment.
Still have a ton of modules lined up for build; another couple ADSRs, mixers and LFOs, and I need to start looking at a master section soon, proper stereo mixing is something I'm sorely missing now that I have several VCOs to play with.
No pictures today due to lack of time, but I'll be sure to post some soon.
I'll post a schem and PCB for my multiple in a bit as I'd love some feedback; it's a very simple circuit so it'd be good to know if I've done my homework with the proper protections etc. |
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