Buchalish 111 Ring Mod PCBs

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djangosfire
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Post by djangosfire » Thu May 16, 2013 12:53 pm

fluxmonkey wrote:
prscrptn wrote:I'm using a .COM PSU; I've metered it and everything appears to be in orde
which one? QPS1 and QPS3 are linear, the others look like switching power supplies, which i've always been wary of. try adding a 10uf cap across the power line, right at the power connector
On the power EDAC? or ?

Thanks!
Thank you - Hope your day is awesome!

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prscrptn
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Post by prscrptn » Thu May 16, 2013 1:03 pm

djangosfire wrote:
fluxmonkey wrote:
prscrptn wrote:I'm using a .COM PSU; I've metered it and everything appears to be in orde
which one? QPS1 and QPS3 are linear, the others look like switching power supplies, which i've always been wary of. try adding a 10uf cap across the power line, right at the power connector
On the power EDAC? or ?

Thanks!
PSU and the EDAC are showing proper and steady voltage.

I tried adding a 10uF cap across power, but still no change. :doh:

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prscrptn
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Post by prscrptn » Thu May 16, 2013 1:48 pm

OK, so I may have figured out the problem...

I was sending the output into a mic input instead of line!

The low level hum is still present, but much more nominal (-52dB).

The sound was probably there before, but so low that I never noticed.

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xi-bot
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Post by xi-bot » Sat Aug 17, 2013 8:19 am

edit: off course the
RA 22k x2 (optional input attenuators)
RB 1k x2 (optional input attenuators)
are the trimmers
stupid me...
Last edited by xi-bot on Mon Aug 19, 2013 12:54 pm, edited 1 time in total.

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logicgate
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Post by logicgate » Sat Aug 17, 2013 8:07 pm

I wonder what you guys have used instead of these??

IT122 (matched NPN pair) x3

2n4916 (PNP) x3


I don't know what to order, those are very expensive at ebay.

How crucial is to have matched transistors on a ring modulator?

Cheers :guinness:


EDIT:

Nevermind, I checked fluxmonkey site and noticed that the BOM there says 2N3904 and 2N3906

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logicgate
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Post by logicgate » Sun Aug 18, 2013 9:55 am

xi-bot wrote:hi

i build the "Romeo Fahl" pcb version. so i wonder were do the four input attenuators belong ?
or are the RB pots output attenuators ?

RA 22k x2 (optional input attenuators)
RB 1k x2 (optional input attenuators)

thanks
HAve you brought the 20K trimmer to the panel? Do you think it's worth the extra step? I'm about to place an order at tayda, and still deciding about getting some 1k and 20K pot's for this. Did you notice any drastic change in the waveform when playing with these trimpots?

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xi-bot
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Post by xi-bot » Mon Aug 19, 2013 12:56 pm

i used 2N3904 and 2N3906
and i was to impatient to match them
but the ringmod sounds nice
logicgate wrote:I wonder what you guys have used instead of these??

IT122 (matched NPN pair) x3

2n4916 (PNP) x3


I don't know what to order, those are very expensive at ebay.

How crucial is to have matched transistors on a ring modulator?

Cheers :guinness:


EDIT:

Nevermind, I checked fluxmonkey site and noticed that the BOM there says 2N3904 and 2N3906

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nordlead
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Post by nordlead » Thu Aug 22, 2013 3:02 pm

Finished my build today (using matched 3904 thanks to Ian Fritz, 12V, no calibration whatsoever yet, unattenuated). Here are some raw sounds with my Serge and a 555-VCO:

http://soundcloud.com/r_c_hoffmann/111- ... lator-test

I wonder if I should bother to use the attenuated ins (not even shure how...), I (already) like the sound as is ...
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(please contact me through email rather than pm: rc at randomsource . net - thanks!)

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fluxmonkey
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Post by fluxmonkey » Fri Sep 13, 2013 11:17 am

first batch of PCBs are sold out, thanks everyone for your support!
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Post by negativspace » Fri Sep 13, 2013 11:31 am

Thanks for the PCBs! :party:

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LektroiD
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Post by LektroiD » Fri Oct 25, 2013 2:16 am

Hope to see a second batch coming soon...

Anyone doing euro panels for this?

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Isaiah
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Post by Isaiah » Tue Apr 01, 2014 5:55 pm

fluxmonkey
I just went to buy a pair of these and they are out of stock (I didn't check this thread first) :doh:
Any chance of another run, please?

Are the to outputs 180 degrees out of phase with each other?

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Isaiah
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Post by Isaiah » Tue Apr 01, 2014 5:55 pm

fluxmonkey
I just went to buy a pair of these and they are out of stock (I didn't check this thread first) :doh:
Any chance of another run, please?

Are the to outputs 180 degrees out of phase with each other?

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LektroiD
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Post by LektroiD » Tue Apr 01, 2014 6:06 pm

I built a home etched version of this one a couple of years ago for my 5U, would love another for my Eurorack, any chance of another run?

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logicgate
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Post by logicgate » Thu Sep 11, 2014 8:57 am

Ok I wanted to start this build and tried to find a build doc for 12V, it seems it never happenned.

Anyways, from a couple of posts I could see it works fine in 12V without much adjustment, and there's the possibility to attenuate the ins - OK.

This is how it's done?

Image


And then we need to amplify the output, ok. So we buffer the out in a piece of perfboard?


Thanks

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elmegil
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Post by elmegil » Tue Oct 06, 2015 6:13 pm

It's ridiculous, I know, but I also just recently finally started seriously looking at this to build it and....

... that don't look like no voltage divider to me :).

I see an input that goes between a 1K to the main circuit and a 22K to ground and I seen an input that goes to the main circuit (the 100K to ground and the 4.7uF cap). If I use the second, I'm just using the unattenuated circuit, but if I use the first, I'm just adding a 1K between the input and the circuit, and an extra 22K to ground for who knows what reason....

Is there supposed to be a trace cut? I could sorta see that working, if you cut between the original input and the 100K and run the attenuator "input" to that 100K, using the original input as your actual input. That puts a voltage divider there, but it's only a 22/23 reduction so that doesn't make sense to me either.

What am I missing? :hmm:

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elmegil
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Post by elmegil » Wed Oct 07, 2015 6:08 pm

Ok, I'm going to try something different.

1) use the alternate inputs
2) omit Ra
3) set Rb to 33K
4) set the 100K input resistor from the original circuit to 10K

At that point I have a voltage divider that should drop 10Vpp to 2.4Vpp.

Simulation makes it appear like it should work.....

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ym2612
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Post by ym2612 » Fri Jul 08, 2016 11:28 am

Edit: found a 111. Thanks to all who PMed me.
Last edited by ym2612 on Thu Sep 29, 2016 3:10 pm, edited 1 time in total.

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prscrptn
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Post by prscrptn » Fri Jul 08, 2016 2:45 pm

^ I've got a panel and pcb's available if anyone needs...

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fluxmonkey
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Post by fluxmonkey » Thu Aug 30, 2018 5:55 pm

I have a new (small) batch available, http://www.fluxmonkey.com/fluxmerch_gear.htm ...
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Post by APETECHNOLOGY » Sat Sep 15, 2018 1:19 am

hold the press!
theres a error in the schematic !
i have the rare opportunity to study a massive 3 panel 100,
i am trying to hunt down unknown errors in the schematics .
found one,
the input 2 resistor is 680 in the schematic, 680k in the original! CBS got us again.
i will post any other discrepancies i find here.ImageImageImage

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fluxmonkey
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Post by fluxmonkey » Sat Sep 15, 2018 5:08 am

Outstanding! and what a great opportunity to get up-close and personal w/ one of the original systems. I'll do some testing to see what difference the change makes, and update information accordingly.
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elmegil
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Post by elmegil » Sat Sep 15, 2018 7:50 am

Is that true for the 680 over on the input 1 side as well?

My copy of the schematic is a lot blurrier than yours :)

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Fernando
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Post by Fernando » Mon Oct 29, 2018 4:53 pm

any update about the 680k being correct?

once or twice in the schematic?
.

Fer

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fluxmonkey
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Post by fluxmonkey » Mon Oct 29, 2018 6:00 pm

I'm posting errata to my pages as I get 'em: http://fluxmonkey.com/historicBuchla/111-ringmod.htm. Here's the resistor in question:

Image

note: I did a test, swapping in the new value on one of the two PCBs on my dual build. Audible difference of the new value was minimal (I doubt I could have distinguished in a blind test), but I will change the PCB legend the next time I do a run.
Fernando wrote:once or twice in the schematic?
These are R27 and R78 on the schematic; since my board is a single ringmod, it's only resistor to change (per board).
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