Search found 148 matches

by johnstilton
Sun Jan 24, 2021 9:41 pm
Forum: General Gear
Topic: Your Favorite Acquisitions in 2020
Replies: 109
Views: 2853

Re: Your Favorite Acquisitions in 2020

Macumbista Benjolin v5

It is so much fun I should have paid for the Dual Butterfly Benjolin.
by johnstilton
Sun Jan 24, 2021 4:16 pm
Forum: Music Tech DIY
Topic: MFOS VCO: why a pair of tantalums instead of electrolytic ?
Replies: 1
Views: 150

MFOS VCO: why a pair of tantalums instead of electrolytic ?

Does anyone know why Ray Wilson chose a pair of tantalum caps instead of electrolytics in the PWM section of his VCO module? C13 C12 And yeah, I’m asking because I left them out of my latest purchase and want to sub them. But I’m also curious to know if not, I would like to learn the why of why not....
by johnstilton
Fri Jan 22, 2021 1:12 pm
Forum: 5U Format Modules
Topic: 5U anxiety
Replies: 21
Views: 696

Re: 5U anxiety

Have you thought about 4U? Serge might be a good way to go. I was going to go 5U but then came to the realization that would have made my project ergonomically difficult and unlikely to be mobile. Even though my current build isn't Serge, I eventually went with 4U as a compromise between Euro and 5...
by johnstilton
Mon Jan 18, 2021 12:34 pm
Forum: Music From Outer Space
Topic: MFOS Quad Timbre Bank Euro build
Replies: 2
Views: 2127

Re: MFOS Quad Timbre Bank Euro build

I'm looking for some feedback from someone else who has a functional MFOS Quad Timbre Bank concerning the CV inputs: One of the things that doesn’t seem correct about mine is that the on the CV inputs of the all channels, both the amplitude and cutoff CVs , do not result in a “zeroed” control if the...
by johnstilton
Fri Jan 15, 2021 3:32 pm
Forum: Music Tech DIY
Topic: fsr circuit design feedback
Replies: 86
Views: 828

Re: fsr circuit design feedback

Current through the FSR is limited by the two 6K8 resistors in series, with 12 volts/13K6 ohms = 0.88mA. Probably safe but if you are using 15 volts then the resistor values should be increased. There is a bit more circuit detail here: https://www.sparkfun.com/datasheets/Sensors/Pressure/fsrguide.p...
by johnstilton
Thu Jan 14, 2021 11:03 am
Forum: Music Tech DIY
Topic: fsr circuit design feedback
Replies: 86
Views: 828

Re: fsr circuit design feedback

The Peasant wrote:
Wed Jan 13, 2021 3:13 pm


Take care,
Doug
Off Topic: Thank you Doug for maintaining your website full of really great DIY builds. It is an inspiration!"
by johnstilton
Sun Jan 10, 2021 12:33 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

I resolved the potentiometer wiring. The CV issues are all still there. Making some measurements, it doesn’t seem like any amplitude or frequency reaches “zero” unless the input is less than -4VDC. I’m going to have to get to know these transconductance amplifiers better. At this point I am also won...
by johnstilton
Sat Jan 09, 2021 10:23 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

I left mine alone for a bit to work on other things and recently got back to it. One of the things that doesn’t seem correct about mine is that the on the CV inputs of the all channels, both the amplitude and cutoff CVs , do not result in a “zeroed” control if the input voltage to that CV if patched...
by johnstilton
Mon Jan 04, 2021 10:13 pm
Forum: Music Tech DIY
Topic: Ian Fritz website... gone?
Replies: 22
Views: 2343

Re: Ian Fritz website... gone?

About 4 1/2 by 5 1/4. Pots mounted along long edge. (If we are talking about the same thing — the board done for Bridechamber.) I purchased one (of the 5U) from Synthcube and it should be in transit. Ian I am not seeing a build guide for it on your site. http://ijfritz.byethost4.com/Chaos/ch_cir6_c...
by johnstilton
Fri Dec 25, 2020 4:52 pm
Forum: Music From Outer Space
Topic: VCA, Increased gain for +/- 15V supplies
Replies: 4
Views: 117

Re: VCA, Increased gain for +/- 15V supplies

Of the two, the VCA on the expander is louder .
by johnstilton
Wed Dec 23, 2020 9:25 am
Forum: Music From Outer Space
Topic: VCA, Increased gain for +/- 15V supplies
Replies: 4
Views: 117

Re: VCA, Increased gain for +/- 15V supplies

I have a MFOS VCA in my Ultimate build and a VCA in its expander. They are 12 volt builds though. The gains between the two seem to be a bit different even though all of the MFOS VCAs are built similarly. I have always assumed that I might have to experiment with some resistor values as I did with t...
by johnstilton
Fri Dec 18, 2020 11:46 pm
Forum: Buchla, EMS & Serge
Topic: Pulse / Clock Divider Interest Check
Replies: 17
Views: 691

Re: Pulse / Clock Divider Interest Check

Yes that is dense.

That is beyond my comfort level of SMT soldering, I am afraid.

Curious to know,
Would the 4MS clock divider suit your purposes?
by johnstilton
Fri Dec 18, 2020 11:14 pm
Forum: Buchla, EMS & Serge
Topic: Pulse / Clock Divider Interest Check
Replies: 17
Views: 691

Re: Pulse / Clock Divider Interest Check

I would be interested in learning more about this .

Is the PCB format going to be akin to that of the CGS modules? Will it be thru-hole?
by johnstilton
Sat Dec 12, 2020 8:23 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

jonnyjupiter wrote:
Sun Nov 15, 2020 7:26 am

Maybe experiment with those 2 resistor values and see what happens? Be sure to let us know.
I'll hopefully get mine wired up next weekend - will pay careful attention to pot pins 1 and 3! Thanks for the warning.
JJ did you get your module wired up? If so what did you discover?
by johnstilton
Wed Dec 09, 2020 10:34 pm
Forum: Music From Outer Space
Topic: Soundlab Ultimate & Ultimate Expander build thread
Replies: 89
Views: 11670

Re: Soundlab Ultimate & Ultimate Expander build thread

Thanks for asking! I got a lot of panel wiring done this spring but then had to take a break because I moved. So far I have finished the panel wiring on the Ultimate and the Expander and the QTB. Both of the keyboard controllers are working as well. Almost everything works with the exception of the ...
by johnstilton
Mon Dec 07, 2020 1:16 pm
Forum: Music From Outer Space
Topic: VCF Four Pole 24dB/Oct With VC Resonance
Replies: 2
Views: 131

Re: VCF Four Pole 24dB/Oct With VC Resonance

Hello, I had the opportunity to get to know Ray's filter design a bit better recently as I was troubleshooting my State variable filter. The part of the circuit with R9 is the control voltage portion of the module. I believe that Q1 and Q2 is a voltage to current converter. The LM13700 is a transcon...
by johnstilton
Fri Dec 04, 2020 11:57 am
Forum: Music Tech DIY
Topic: Ian Fritz website... gone?
Replies: 22
Views: 2343

Re: Ian Fritz website... gone?

Thank you Ian for pointing me out in that direction!

Can you tell me what the dimensions are of the 5U PCB ?
by johnstilton
Fri Dec 04, 2020 9:13 am
Forum: Music Tech DIY
Topic: Ian Fritz website... gone?
Replies: 22
Views: 2343

Re: Ian Fritz website... gone?

Wow, after reading about the chaos theory stuff I really want to implement a Chaotica into my build.

Is there no other option to buy full Eurorack kits? I am building on full 4U panels and not building in the eurorack format and don't need the panel or sub-mounting PCBs, just the main PCB.
by johnstilton
Mon Nov 16, 2020 3:09 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

Taking a closer look at the circuit after BUF the signal is attenuated by a voltage divider comprised of R10 680K and R14 1K which is a magnitude of only 0.0014. So if you input a 5Vpp signal the Input buffer tries to amplify it to the rails. Backing off the input level to something closer to the or...
by johnstilton
Sat Nov 14, 2020 7:17 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

So it turns out I plotted my pots “backwards” so the outside legs are reversed on all twelve of them. So everything, reequency, resonance, amplitude was full screaming when I thought theY should be off. One thing I noticed right away was that my signal at BUF is amplified. Did anyone notice that the...
by johnstilton
Wed Nov 11, 2020 6:01 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

I always procrastinate with the wiring to the front panel. Busy this weekend, but will get to it shortly. Will let you know if I have any self-oscillation issues. Any particular filter or the whole device? At all resonance levels? BP and/or LP? The whole device is. No control of anything just a rai...
by johnstilton
Tue Nov 10, 2020 6:49 am
Forum: Music From Outer Space
Topic: MFOS Ultimate LFO CV Input modification?
Replies: 4
Views: 1426

Re: MFOS Ultimate LFO CV Input modification?

I did compare them. They are significantly different
by johnstilton
Mon Nov 09, 2020 10:45 pm
Forum: Music Tech DIY
Topic: MFOS Quad Timbre Bank, Eurorack
Replies: 42
Views: 1940

Re: MFOS Quad Timbre Bank, Eurorack

I am also following. I built one and am going to start the troubleshooting this weekend because it’s self oscillating uncontrollably
by johnstilton
Mon Nov 09, 2020 8:45 pm
Forum: Music Tech DIY
Topic: Assistance needed troubleshooting MFOS state variable VCF
Replies: 13
Views: 234

Re: Assistance needed troubleshooting MFOS state variable VCF

Apparently I’m supposed to put a jumper here ! 1D2D6012-9120-435C-8B54-835FF31B6C5C.jpeg I only had +5v going to X2 for the cutoff pot. I seem to have a functioning filter now and will see about optimizing it this weekend. I am glad that it was (relatively) an easy problem to find! More importantly ...

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