Buchla 111 Ring Mod Layout

vtl5c3 · Posted: Sat Jul 11, 2009 5:57 pm Post subject: Buchla 111 Ring Mod Layout

OK, Kiddies! Here's another Buchla pcb layout for you to play with. This time it's the 100 series ring mod, based off the schematics on the interweb (sorry can't find the link ATM)....

THis one is untested by me, but the layout matches the schematic 100%. I triple checked before I posted it.

I have a board etched and partially stuffed, but a low back injury has me momentarily immobilized. I will try to complete it as soon as I recover.

Anyway, happy summer!

Romeo

Buchla111_PCB.pdf

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Updated PCB Layout and Parts placement diagram. 7/31/09

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Buchla111_PCB.pdf

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Funky40 · Posted: Sat Jul 11, 2009 6:03 pm Post subject:

wow, thanks alot !
And i wish you good recovery

ff

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

vtl5c3 · Posted: Sun Jul 12, 2009 10:20 am Post subject: ¡esquimatico?

Here's the one I got off the interweb. And now it's time for bacon!

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vtl5c3 · Posted: Thu Jul 23, 2009 10:17 am Post subject:

Quick update: I soldered most of the components to my PCB last night. I'm waiting for mouser to send me a replacement trimmer, since they sent me a broken one. I hope to be able to test it by the end of next week.

R.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

This is in my que. Thanks again for posting.

I drew layouts for the 106 mixer and 170 Preamp, for practice, and because they were easy. I need to re-do them on graph paper or some program. What do you use for your layouts (like this 111)?

vtl5c3 · Posted: Thu Jul 23, 2009 1:55 pm Post subject:

I usually start in Photoshop 5.5, using the line tool. I then finish up in Photoshop CS2. Not an ideal workflow, but I learned it when that was the best I had to work with. I'd like to learn Eagle or some other PCB layout program, but you know how that goes....

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

vtl5c3 · Posted: Fri Jul 24, 2009 8:03 am Post subject:

Hold off on the 180, since I already have a layout for that. I'll clean it up and post it before long.

Fernando · Posted: Mon Jul 27, 2009 9:00 am Post subject:

nice and inspiring Romeo! as usual

any sound yet?

it is a discrete four quadrant multiplier?

vtl5c3 · Posted: Mon Jul 27, 2009 9:33 am Post subject:

Hi Fernando,

It's all soldered and wired to a front panel. I'm just waiting for a replacement trimpot from Mouser. I hope to have it running by the weekend, providing that there aren't errors in the schematics. As far as I can tell, it is a four quadrant multiplier.

vtl5c3 · Posted: Thu Jul 30, 2009 10:03 pm Post subject: Progress

So I've been testing it since last night. Last night it was completely not working. I'm using the new Kobicon 1/8" jacks from mouser and wired everything up incorrectly, because they changed the pinout. On top of that, they are flimsy. I will have to find better jacks.

Tonight I made another attempt, this time with the jacks wired correctly. The signal is getting all the way to the bases of the output transistors (Q9 & 10), but not any further. My guess is that R39 & 40 need to be changed since I subbed 2N3906s for the PNPs in the original circuit. They are probably not getting turned on enough to pass the signal through. I will experiment further in the next few days and let you know how it goes.

R.

vtl5c3 · Posted: Fri Jul 31, 2009 10:09 am Post subject:

I think I found the problem. The CBS/Buchla Schematic has an error in it. R38, the 47Ω resistor that goes from Q8's collector to Q10 and the top matched pairs should actually connect to V+. Luckily I have two other versions of this schematic that don't have this error. I'll update the PCB layout ASAP.

R.

vtl5c3 · Posted: Fri Jul 31, 2009 6:28 pm Post subject: Success!

Quick update: I modified the the 47 ohm resistor as mentioned in my last post. Now it works like a charm! I've updated the PCB layout at the beginning of this thread. In my version I used MAT02s for the matched pairs, but it's quite likely that any matched NPN pairs will work.

To my ears it sounds like most other ring modulators, but I'll give it more of a workout this weekend to see if it has any unique characteristics.

Buchla_111_fix.jpg

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Fix to CBS schematic

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LektroiD · Posted: Sun Dec 19, 2010 8:20 am Post subject:

I'm thinking of building a couple of these but the matched transistors are prohibitively expensive (if available). The diagram posted suggests you can match your own, however the originals are dual monolithic transistors, and by the looks of things these are rather complex designs:

vtl5c3 · Posted: Sun Dec 19, 2010 9:42 am Post subject:

My 2 cents: try it!

I'd be surprised if the design didn't work with hand-matched transistors. There's plenty of trimmers to compensate for mismatches.

tokyomatik · Posted: Thu Feb 23, 2012 10:05 pm Post subject:

anybody verified if this layout works?

vtl5c3 · Posted: Fri Feb 24, 2012 8:05 am Post subject:

Worked for me.

tokyomatik · Posted: Fri Feb 24, 2012 12:35 pm Post subject:

is it possible to make it work also at +12v ?

tokyomatik · Posted: Fri Feb 24, 2012 12:43 pm Post subject:

....ehm....and would be possible to listen some samples? Razz

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

vtl5c3 · Posted: Mon Feb 27, 2012 10:27 pm Post subject:

I was playing it tonight. It's very old school sounding... similar to the CGS ARRM, maybe.... I'll post some mp3s to demonstrate.

LektroiD · Posted: Mon Feb 27, 2012 10:38 pm Post subject:

I'm stuck looking for 5.6µF tantalums.. I'm thinking of using 6.8µF tants in their place.

Also I'm using 2n3904/2n3906 throughout.. I'll report back once I have it finished

vtl5c3 · Posted: Tue Feb 28, 2012 8:57 pm Post subject: audio sample

LektroiD · Posted: Wed Feb 29, 2012 8:14 am Post subject:

I've just finished this. It works and sounds awesome...

I used 6.8µF Tantalums in place of the 5.6µF Tantalums.
I used 2n3904/2n3906 transistors throughout and none have been matched - as someone mentioned earlier in the thread, there's enough presets to compensate for this.

I'm not sure of the calibration method, but I ran a sine through one input, calibrated until no sound was present, then did the same with the other input. I'm actually liking this more than my Moog ring mod! Really smooth and well rounded sound, even at high frequencies.