Search found 17 matches

by ljwall83
Fri Dec 04, 2020 3:36 am
Forum: Modular Synth General Discussion
Topic: Counterpoint with modular
Replies: 31
Views: 538

Re: Counterpoint with modular

I feel the need for another Doepfer A-155/A-154 combo :help: Since we are speaking of short sequences, the A-155 can take 8 inputs for the lower CV row (and with the A-155/A-155/A-154 trio you can have 16). With the A-154 controller you can decide how the sequence is played, en which part of it (if...
by ljwall83
Wed Dec 02, 2020 11:56 am
Forum: Buchla, EMS & Serge
Topic: My take on the CGS / Serge Programmer
Replies: 41
Views: 1898

Re: My take on the CGS / Serge Programmer

BY THE WAY, the boards and panels just arrived here, so I'll be packing the first orders up over the next week or so. Keep an eye on the PayPal orders for tracking info. Sweeeeet! I've been resisting the urge to message asking for an update, since the site did say up to4 weeks and it nowhere near t...
by ljwall83
Sun Nov 29, 2020 6:41 am
Forum: Music Tech DIY
Topic: 100k input resistance... isn't
Replies: 89
Views: 2071

Re: 100k input resistance... isn't

Is that less of a problem with bananas anyway? Since, unlike eurorack, you're not briefly shorting the output to ground every time you patch it? You still get lots of incidental shorting on 4U just from jacks bumping against each other when you're patching, or shorting on case fittings etc. It's ge...
by ljwall83
Sat Nov 28, 2020 4:05 am
Forum: Music Tech DIY
Topic: 100k input resistance... isn't
Replies: 89
Views: 2071

Re: 100k input resistance... isn't

CLee wrote:
Fri Nov 27, 2020 8:59 am
And this from the VCFQ, where (as mentioned earlier as a problem) the output is fed back to internal circuitry.

Cgs_schem_cgs112v1.0_vcfq CROP.jpg
Is that less of a problem with bananas anyway? Since, unlike eurorack, you're not briefly shorting the output to ground every time you patch it?
by ljwall83
Mon Nov 23, 2020 6:16 am
Forum: Buchla, EMS & Serge
Topic: My take on the CGS / Serge Programmer
Replies: 41
Views: 1898

Re: My take on the CGS / Serge Programmer

Order placed! :mrgreen:

Just gathering some parts. On the BOM the the pot value column says 100K but the supplier part number has B250K --- I'm guessing the 100K value is the right one?

Edit: I guess I can answer this myself really by looking at the Ken stone documentation.. :doh:
by ljwall83
Sun Oct 18, 2020 3:01 pm
Forum: Music Tech DIY
Topic: Solution to clogged hole with solder
Replies: 24
Views: 504

Re: Solution to clogged hole with solder

The technique i use which I find very effective (using a no-brand bargain basement solder sucker): Hold the PCB vertical with something. Apply heat to one side, use solder sucker from the other side.
by ljwall83
Mon Sep 28, 2020 8:02 am
Forum: Music Tech DIY
Topic: Turing Machine V1 stopped locking the sequence.
Replies: 15
Views: 205

Re: Turing Machine V1 stopped locking the sequence.

Not sure how much digging you want to do, but right on page 1 of this thread https://www.muffwiggler.com/forum/viewtopic.php?t=159116 there is a suggestion of which resistor to replace with a trim-pot. If you or someone you know is hand with a soldering iron you could give it go. I've only skim read...
by ljwall83
Mon Sep 28, 2020 1:46 am
Forum: Music Tech DIY
Topic: Turing Machine V1 stopped locking the sequence.
Replies: 15
Views: 205

Re: Turing Machine V1 stopped locking the sequence.

I've just been reading the long Turing Machine threads to try to work out if my Mk2 build is working correctly.

Anyway, from reading that, I think the trim pot was added in Mk2 unfortunately.
by ljwall83
Sun Feb 23, 2020 6:23 am
Forum: Music Tech DIY
Topic: Audio mixer and running signal through pots
Replies: 8
Views: 544

Re: Audio mixer and running signal through pots

Thanks for the answers folks!

I guess this was verging into stupid-question territory --- but good to know nevertheless. I will build my next DIY mixer module with confidence :mrgreen:
by ljwall83
Fri Feb 21, 2020 11:35 am
Forum: Music Tech DIY
Topic: Audio mixer and running signal through pots
Replies: 8
Views: 544

Audio mixer and running signal through pots

In designing a basic audio mixer for a modular synth, with no voltage control, just manual control, is there any good reason to use still use a VCA-type circuit to avoid running the signal though front-panel pots? I realise there are a million circuit designs on The Internet that do run the signal t...
by ljwall83
Wed Sep 25, 2019 8:51 am
Forum: Music Tech DIY
Topic: Potentiometers with center tap, where buy?
Replies: 12
Views: 1059

unauthorised-service wrote: I used this scheme with resistors .
:hmm:

I've never used one, but I'd assumed that most cases the point of using a center taped pot is to set the voltage on the sweep pin at the center point, not to read to center point voltage?
by ljwall83
Tue Sep 17, 2019 2:53 pm
Forum: Music Tech DIY
Topic: Best practice regarding buffering & impedance, ground?
Replies: 22
Views: 1518

thanks devinw1. Was reading about TVS diodes in the context of power supplies just the other day --- didn't connect the dots with regard to general input/output protections on other devices..
by ljwall83
Tue Sep 17, 2019 1:35 pm
Forum: Music Tech DIY
Topic: How does this through zero linear FM input circuit for the C
Replies: 6
Views: 900

Thanks everyone here ---- this is dead handy. I was just waiting for my request to join the Synth DIY facebook group to be approved. Going to have close read of these. Sad to read the 3340 implementation perhaps doesn't work too well. I'm pretty sure I don't have the chops to succeed with making it ...
by ljwall83
Tue Sep 17, 2019 12:31 pm
Forum: Music Tech DIY
Topic: Best practice regarding buffering & impedance, ground?
Replies: 22
Views: 1518

I admit I had not considered ESD. What's a good inline resistor value to protect against that?

I guess by the same token, an inline resisistor on inputs could be useful? Though I've seen a lot of designs without. Or is the high impedance of, say, an op amp input, protection enough?
by ljwall83
Tue Sep 17, 2019 6:20 am
Forum: Music Tech DIY
Topic: How does this through zero linear FM input circuit for the C
Replies: 6
Views: 900

How does this through zero linear FM input circuit for the C

Can anyone explain how this through-zero linear FM input stage works, or at least provide a couple of pointers? http://jhaible.com/legacy/tonline_stuff/hj2vco.gif It's a design by Juergen Haible: the dual VCO link in the JH 3 section here: http://jhaible.com/legacy/tonline_stuff/hj_modul.html . I fo...
by ljwall83
Tue Sep 17, 2019 4:56 am
Forum: Music Tech DIY
Topic: Best practice regarding buffering & impedance, ground?
Replies: 22
Views: 1518

Sorry --- I should have read the links more fully before asking this question above ^^^. Seem like the answers are all in there, and the TL07X don't actual need current limiting resistors: those resistors are there either to serve other purposes, or because cargo-culting. Gonna read this all more th...
by ljwall83
Tue Sep 17, 2019 4:28 am
Forum: Music Tech DIY
Topic: Best practice regarding buffering & impedance, ground?
Replies: 22
Views: 1518

This is handy --- I'm just starting to design a first Eurorack module of my own (well, connect some standard circuits into a cohesive whole). Sounds like to interface with other Euro rack modules you're more or less obligated to keep your input impedance up at 100k, but output could go down to whate...

Go to advanced search