As I have no idea to which mods you are referring I would assume that I have not. Do you have link for this ?
I did just google it but I have not been successfull…
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There are some capacitors mentioned on muffwiggler to reduce noise, I built a 6 voice poly with these chips, but to make it more usable I also installed this software and mods.
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Finnaly sorted power in my case.
Got a C14 socket with fuse:
Then some up-to-code connectors to an internal wallsocket for the warts for the FC Speak Truth to Power busses. And future proofed for the LED powersupply as well. (Which is why I need 240VAC in the case to begin with)
Don’t worry, nothing of the 240v is exposed.
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nice case , you will have that filled up in no time though 
. good to see all of the AC safely covered ! .
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Thanks for the link. I cant find much infos regarding extra capacitors. I have added a couple 150nf on each output and it did help. I am not that fussy for things being perfect but for people who are I guess that chip (and basic schematic) can be a bit of a headache…
Try a 220nF cap between pin 17 and ground to clear up the noise.
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Scope module seems fully working. There were some little problems like the too wimpy regulator and inaccessible test points and the afterthought power switch arrangement, nothing that couldn’t be ignored or worked around. Then I realized I’d used a non inverting buffer on the input, forgetting about TL07x phase reversal. Moreover I’d used two op amps to buffer it twice when I could have used them as a single pair of inverting stages. Sheesh. One design flaw too many, think I’ll get a revised PCB done. And a front panel of course.
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Very short demo of my breadboarded spring reverb. Using an accutronics 8EB2C1B tank with Tombola’s spring reverb circuit which is found here.
Not sure if this is the circuit I want to actually solder. Does anybody know if the circuit of the Doepfer A-199 reverb module is publicly available somewhere? would like to compare it.
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Note Tom Whitwell later (2017) also designed this much more elaborate version:
which includes the option of using a spring tank, an Accutronics brick, or both (if you add the expander, which basically is just a pot along with front panel accessible jacks for the tank), and has feedback and CV controlled wet/dry mix.
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Just completed this XOR Percs module!
Take a listen:
Original circuit based closely on @analogoutput’s:
Itself based on Elliot Williams’ & many classic CMOS circuits:
I just need to flip both channels after I remove it from the frame, an easy fix, since it’s wire wrap.
My first complete wire wrap project, actually. I know it’s a technique that’s no longer in fashion, but it’s definitely working out well with my way of building modules. While you can’t find cheaply the sort of IC holders the technique calls for, pin headers work just as well.
Nerd hieroglyphs:
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The luxury toy situation got a little out of controll. only three missing till i have the entire collection…
for clarity:
- #33 is not in the picture
- the ones i am still hunting for are: #20, #28, #35
- i try to get them for reasonable prices!
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My build progress is super lame but hey! It’s something. Did my first soldering in what I think is about a year this last week. Here’s my on-the-go projects. Which sadly looks almost the same as it did about a year ago…
There are three projects here. Two VCOs, a HaraldsWerk CV mover, and a Kassutronics Slope. There have been pot shortages for a good long time now. I check in with the American diy synth stores periodically and have never seen the pot values I need in stock. Tayda has them but my last few tayda orders I got hit with insane duties charges so I’ve been order shy.
I was browsing the other day and saw Mouser sells the pots, pretty expensive compared to Tayda, but for a small order I think it’s cheaper with them once the duties are involved, so I’m soldering up everything I have to see what I need to order and hopefully this payday I can order parts to at least do the Slope. Money is tight but that’s the most useful to me module right now and I think I can swing it.
Other problem is the CV mover … Values aren’t printed on the board and I can’t find where I got these boards from. Need to dig a bit more
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Wife wanted the MegaMan one and I had to break it to her just how much it is.
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Well, the board says haraldswerk.de so I had a look there and found the schematic, which shows all values …
B.t.w. you do not in all situations have to stick religiously to the values of potentiometers you see in a schematic! In quite a few situations you can allow yourself some freedom when choosing the value of a potentiometer.
E.g. in the haraldswerk CV-mover (schematic here) the pot P1 is a mere signal attenuator and changing its value does not so much influence the circuit itself as it does the signal source you connect to it via the IN-connector. What I mean is, that you can easily use a 10k, 20k, 50k pot or a 250k pot in stead of the 100k pot without experiencing any difference. Just remember that the pot P1 as a whole is a load for the circuit connected to IN. If that circuit has a low output impedance, then P1 will only be a small load for it and not noticably change the signal. Often the output impedance of a circuit is aimed at 1k Ohm, so as long as the pot’s resistance is much larger than that, you should be ok. In the same schematic P2 is another matter. Its value is meant to provide a bias value or offset value for IC1B and it is tuned to the 2 resistors R8 and R13, but if you were to use a different value for P2 and scale both resistors accordingly, you should be ok as well.
If a pot is used to set some voltage used by an opamp used as a comparator, then also often you can choose a different value pot, as long as it is capable of providing the voltage the comparator needs.
If a pot is part of a timing circuit, e.g. part of an envelope generator, then things get a bit more complicated because of its dependency on other components of the circuit and then I would recommend against choosing a different one unless you are more experienced in these things.
Ok, you may think this choosing your own value is maybe something only for people with advanced knowledge but experience has taught me that it does not hurt to try another value and that is one way of learning, isn’t it? Compared to the hollywood nonsense about electronics and electricity in actual practice hardly ever things go up in smoke, which is sort of dissapointing in a sense.
So don’t be afraid to try it!
Thank you for the info! I think this is really useful but I’m on a sick day today and have mad brain fog, so I’m not really processing information properly. Will give a reread when I perk up a bit.
And thanks for the link too! Looks like he has two different CV Mover modules for different formats. I was finding this one - www.haraldswerk.de CV Mover which is obviously not the right one, so I thought I must have found Gerbers from someone else who modified it
For what it’s worth (probably very little!) there’s this old topic:
Presumably some of that information is out of date and it’s decidedly mostly USA-centric. But maybe there’s something helpful there.
I had to take a few weeks off synth-building to finish up this thing:
After 3 long years our parade finally took place again. And best off all, we took first place again 
. This was one hell of a process, we crammed more than 150 motors into the float, ranging from tiny 5v servos and 24v DC motors, to 5kW 400VAC behemoths. For results, see at 1:46:
Now where did I put that synthesizer…
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Indrukwekkend, zeer indrukwekkend!
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