Buchla Source of Uncertainty 266

vtl5c3 · Posted: Tue Mar 10, 2009 3:16 pm Post subject:

Hi FF,

In my layout, the NC socket would connect to the point just beyond the output of the MM5837 IC. If you wanted to input noise at point 'a', you probably should use something to protect the CD4016 inputs.

funkyfarm · Posted: Tue Mar 10, 2009 7:42 pm Post subject:

266-3

FLUCTUATING RANDOM VOLTAGE

numbertalk · Posted: Thu Mar 12, 2009 6:33 am Post subject:

vtl5c3 - is the pdf of the pcb image for the 2nd board updated with the latest fixes yet?

Thanks!

vtl5c3 · Posted: Thu Mar 12, 2009 8:40 am Post subject:

Hi! Yes. The one that's posted has the fixed traces. I haven't added pads for 10uF caps after the ferrite beads, but it will work without them.

funkyfarm · Posted: Thu Mar 12, 2009 12:22 pm Post subject: Subject description: RV

numbertalk · Posted: Fri Mar 13, 2009 6:01 pm Post subject:

Thank you!

funkyfarm · Posted: Sun Mar 15, 2009 3:06 pm Post subject:

266-2 STORED RANDOM VOLTAGE

Hi,

I need your opinion to know if my SRV works or not.
I've connected the probability pot between 0 and 15V (instead of 12), and I find it cool from position 10 to 4 (distribution decrease), then distribution begins to increase upto position zero.
12v is not available on board, right ?
You've put 10v ?

schematic

Here is few sample where I slowly turn pot from cw to fully ccw (stay a few seconds in the middle position).

Without any clock signal
With input clock in
Potentiometer fully ccw with CV (lfo triangle +/-5V)

Do you hear any sweep on output 2 as you turn the potentiometer ?

billy pilgrim · Joined: Feb 12, 2008 Posts: 36 Location: nyc

Vtl3c....This is a such great project.....

I've just started to build the QRV 266-1 and I notice that on the 4070 pin 7 is tied to 10v. I would have thought it should be 0v ? Is this correct What am I missing ?

vtl5c3

Hmmm.... I think I may have made a mistake. Good eye! Let me check my work. I'll update the PCB if necessary.

vtl5c3

OK, you were correct about the CD4070. Thanks for pointing it out. My parts placement diagram had it upside down. One of the traces was off too. I've corrected the layout and diagram and posted the changes at the beginning of this thread.

Romeo

billy pilgrim · Joined: Feb 12, 2008 Posts: 36 Location: nyc

That's great, thanks for figuring it out.

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

Anyone here tackle board 4 yet? Although it's been a while since I've looked at it, I had some problems with mine. Just wondering what other's experience has been?

Photon · Posted: Wed Apr 08, 2009 6:32 am Post subject:

Soon! I'm etching a front panel for this today (along with the 208 URV).

What problems are you having?

funkyfarm

vtl5c3 · Posted: Mon May 11, 2009 1:39 pm Post subject:

Hi FF,

I'm a little strapped for time ATM, otherwise I'd create a graphic showing the differences. If you print out the new layout and compare to the old one - just the traces under the CD4070 - you'll see what's different. Just a trace or two that needs to be cut, IIRC.

R.

funkyfarm · Posted: Mon May 11, 2009 4:01 pm Post subject:

Thank you.

(I got it ; pin "14")

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

This project is finally getting me to try PnP. I've been scared to do it, but even if I mess up a few boards at first does me more good than daydreaming about it. I've got some 8"x10" boards so I am just trying to panel a few things together. Including these and a few 258s.

I am looking forward to making some kind of portable Buchloid performance thing, kind of like the Sili-Con Cello. If these PCBs turn out decent then I might try doing a few layouts myself.

vtl5c3 · Posted: Wed May 13, 2009 6:46 am Post subject:

Glad to hear that you will try out the 266! PnP is not hard to figure out. The most important thing I've found is to have a clean copper board. I like to clean it with steel wool and vinegar (or dish soap) so that it gets a fine scratched/brushed texture and very clean. That seems to help the toner stick to the copper. The other tip I can pass on is to keep a close eye on the iron's temperature. If it gets too hot, the PnP plastic wrinkles and that screws it up. Also, if you really goof up when you iron the PnP to the copper, you can just scrub it off and do it over. Anyway, good luck!

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

what he said: don't be scared of PnP, and definitely take care in the pre-cleaning of the board, that is the secret. also: if the transfer isn't perfect, you can usually touch it up w/ a Sharpie marker, which is also an etch resist.

for myself, i wouldn't try combining projects and etching one big board. i will combine designs on to one sheet of PnP, but then i cut them apart and transfer/etch one at time. it make the heat transfer process easier (the larger the board, the harder to apply even heat and pressure all over), also etching (smaller tank, less etchant).

good luck!

b

LetterBeacon · Joined: Mar 18, 2008 Posts: 454 Location: London, UK

I've only just started etching my own boards and found it a lot easier than I thought it was going to be. I spend a lot of time cleaning the copper boards beforehand.

So out of the four boards, which ones are confirmed as 100% working? From reading through the thread it looks as though 266-1 and 266-2 have been updated and are working, has anyone completed 266-3 or 266-4?

I only ask because I have limited access to a laser printer and so I need to know that what I'm printing is going to work!

funkyfarm · Posted: Wed May 20, 2009 2:09 pm Post subject:

Board 1 - 266_1 - Quantized Random Voltages

I think one 457 diode is upside down around 2^n output ; P regions are connected together on schematic.

vtl5c3 · Posted: Wed May 20, 2009 2:51 pm Post subject:

>ouch!< You caught another one. Good eye!

OK, I fixed the parts placement guide at the beginning of this thread. Thanks for pointing it out. Now I need to check my actual board and see if I made the same mistake on it.

R.

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

inform3r · Joined: Sep 03, 2006 Posts: 59 Location: nyc

Wow vtl5c3! Quite an undertaking here. Thanks! I've read the thread a couple of times. I'm just getting around to plotting things out. Planning the panel, etc.... For now I'm just curious about one thing.... I know you added a couple of features here and there. You added the possibility for people to inject their own noise source via a jack for instance. Well, if I decide to keep the module without certain additions can I just leave the associated pad alone and everything will be cool? No need to jumper it or anything? Sorry, just curious and taking it slow.

Best Regards,
John

inform3r · Joined: Sep 03, 2006 Posts: 59 Location: nyc