Buchalish 111 Ring Mod PCBs

appliancide · Post by **appliancide** » Tue Jan 15, 2013 1:26 pm

bsmith...can you describe the difference between the attenuated and unattenuated module?

I never realized that Buchla audio signals were line level (or close to it).

bsmith · Post by **bsmith** » Tue Jan 15, 2013 1:39 pm

heya appliancide - yeah I think it's a bit cleaner ring mod sound with the attenuated, and there is more usable play with the couple trimmers that I found to be useful. Been a couple weeks I've been using it and I think it's a lovely ringmod. Check out both though - I'm sure some may prefer the grittier non-attenuated - I've kind of found a middle ground I like with the help of that 20k trimmer.

Funky40 · Post by **Funky40** » Tue Jan 15, 2013 1:44 pm

anybody built without mathching the transistors ?
is it really that much recommended to match ?

bsmith · Post by **bsmith** » Tue Jan 15, 2013 1:47 pm

I didn't match - but I did use consecutive ones from a reel....

FetidEye · Post by **FetidEye** » Fri Jan 18, 2013 8:09 am

the bom says 4x 10k, but on the pcb it says 2x 10k and 2x 10r

what should i use? or is it a typo?

and about matching the transistors:
can i buy matched pairs , or is it easy to match 'm myself?
i checked out this pdf: match but it would be great if someone can help me with this.. (i'm not so good with math)
breadboard pics anyone?

bom errors:
there are 4 x 1k5 (instead of 1) resistors on the pcb
missing: 10uf condensator

fluxmonkey · Post by **fluxmonkey** » Fri Jan 18, 2013 12:40 pm

Project documentation and PCB component values are correct... i fixed the BOM on the first page of this thread.

FetidEye · Post by **FetidEye** » Fri Jan 18, 2013 1:15 pm

ok

any tips on the matching?

hexinverter · Post by **hexinverter** » Fri Jan 18, 2013 1:18 pm

FetidEye wrote:ok

any tips on the matching?

That is a complex subject, but, Ian Fritz has a nice .PDF article on what I consider the easiest and best method of transistor matching. A search should turn it up

EDIT d'oh, the one you linked is the one that I am referring to.

There is no math needed really...it's just subtraction if I recall correctly. You don't have to fully understand his mathematical explanation there -- just skip to the important bits so you understand how to match them based on his guide

rowman · Post by **rowman** » Fri Jan 18, 2013 6:58 pm

The schematic says to use tantalum caps, any particular reason not to use electrolytics?

elmegil · Post by **elmegil** » Sat Jan 19, 2013 10:39 pm

fluxmonkey wrote:
bsmith wrote:Did want to ask about optional attenuated ins...

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

looks like we can have standing resistors on either side of a pad for ins there - how is this meant to be wired for attenuation?
yep, that's an optional passive voltage divider for folks using this in conjunction w/ non-buchla modules. they'd need to drop the input signals, and then boost the output w/ a buffer amplifier--suggested values based on ken stone's stomp box adapter which is what i used in my testing. omit both pairs and use In1 and In2 for buchla (1.2v) levels.

I just got my board (THANKS!) but I don't really grok this.

I thought ring mod was for audio chain, not control chain, so why would 1.2V matter?

I'm using a 15V mostly MOTM format systems, mostly Thomas Henry modules.

appliancide · Post by **appliancide** » Sun Jan 20, 2013 1:09 am

elmegil wrote:
I thought ring mod was for audio chain, not control chain, so why would 1.2V matter?

I'm using a 15V mostly MOTM format systems, mostly Thomas Henry modules.

That isn't a reference to the 1.2V/Oct standard of Buchla. Apparently the audio signals are about 1.2Vp-p, compared to the 10Vp-p signals used in most other systems.

elmegil · Post by **elmegil** » Sun Jan 20, 2013 1:42 am

Ah, I was not aware of that. Thank you :-)

djangosfire · Post by **djangosfire** » Wed Feb 27, 2013 1:59 pm

Hi guys -

I'm putting together a Mouser order for this 111 pcb.

I still get confused when it comes to capacitors . . . .

What voltage range should I be concerned with?

Looks like electrolytic is OK in place of the tantalum ??

Also, there appears to be 4x 1k trimmers?? And 1x 20k trimmer?? The BOM does not say.

Any help/tips greatly appreciated.

Thanks very much!!

- Adam

prscrptn · Post by **prscrptn** » Wed Feb 27, 2013 2:16 pm

fluxmonkey · Post by **fluxmonkey** » Wed Feb 27, 2013 3:40 pm

i always use electolytics rather than tant... works fine, but i can't give an informed opinion on if it sounds any different. for that matter, i've always used 4.7uf instead of the specified 5.6... again, seems to work fine.

and yes, sorry, the trimmers are missing from the BOM. as stated, you need four 1k and one 20k trimmers per board: 3299Y-1-102LF and 3299Y-1-203LF from mouser. i'll get the doc revised, my apologies.

djangosfire wrote:Hi guys -

I'm putting together a Mouser order for this 111 pcb.

I still get confused when it comes to capacitors . . . .

What voltage range should I be concerned with?

Looks like electrolytic is OK in place of the tantalum ??

Also, there appears to be 4x 1k trimmers?? And 1x 20k trimmer?? The BOM does not say.

Any help/tips greatly appreciated.

Thanks very much!!

- Adam

raisinbag · Post by **raisinbag** » Wed Feb 27, 2013 8:01 pm

Hey flux, just looking at your site and there seems to be a "link" to a frac fpd panel design, but it isn't activated. Can you shoot me a copy? I'm on a panel etching junkit this weekend.

just lookIng for some ideas for where to start this one.

fluxmonkey · Post by **fluxmonkey** » Wed Feb 27, 2013 9:30 pm

sorry, that's a copy/paste fail. i never made a FPD panel for this one--mine's still sitting behind a piece of raw blank aluminum. 2 in, 2 out, how hard can it be?

raisinbag wrote:Hey flux, just looking at your site and there seems to be a "link" to a frac fpd panel design, but it isn't activated. Can you shoot me a copy? I'm on a panel etching junkit this weekend. just lookIng for some ideas for where to start this one.

raisinbag · Post by **raisinbag** » Wed Feb 27, 2013 9:37 pm

hahhahahahaha ok 2in 2 out, I can ger artistic then. I think someone was using a pot for a trimmer, so I was kinda curious about that. I guess I can pop a hole in later if this is fun.

ok then off to play match maker with some trannys.

FetidEye · Post by **FetidEye** » Sat Apr 13, 2013 10:47 am

finished finally

working on 12v
i use the RA and RB inputs
no panel yet .. and didn't use matched 3904's
(matching those is still out of my league)

sounds great!
thinking about bringing that 20k to the front..

what do those 1k trimmers do?

prscrptn · Post by **prscrptn** » Wed May 15, 2013 5:16 pm

Having a problem and wonder if anyone can help...

My 111 has a low frequency hum around 180Hz which is present regardless of any signal on the input. This is the second unit that I've built and the first one had no issues.

I am using the same components/values and have checked all traces and adjusted trimmers. The problem is present on both boards and I have tested them independently, same issue...

Any thoughts?

fluxmonkey · Post by **fluxmonkey** » Wed May 15, 2013 8:59 pm

backchannel you'd mentioned that you're using a new power supply... what kind? do you have the old supply available to swap in?

elmegil · Post by **elmegil** » Wed May 15, 2013 9:32 pm

So I also replied to your PM, but

1) I haven't actually built this circuit

2) I didn't remember you saying both boards, so each ring mod is a separate board? If so my advice in PM isn't worth much :-)

My speculation would be something wrong with the tantalum caps, but that's a total SWAG and I'd check flux's question about the Power Supply first.

prscrptn · Post by **prscrptn** » Thu May 16, 2013 5:56 am

I'm using a .COM PSU; I've metered it and everything appears to be in order.

I can not find any errors and the circuit works, but the hum is still present...

fluxmonkey · Post by **fluxmonkey** » Thu May 16, 2013 7:09 am

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

prscrptn · Post by **prscrptn** » Thu May 16, 2013 7:46 am

Hmmm...QPS4, i will try adding the cap, thanks!

MUFF WIGGLER

MUFF WIGGLER

Buchalish 111 Ring Mod PCBs