Making Music with the 566 now available

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

So what are the differences between the Signetics and the National 566s in an application like this? Are they really that different or is this just folklore? Are the Nationals worth using?

Dave

Dan Lavin · Posted: Tue Dec 04, 2007 2:30 pm Post subject:

loss1234 · Posted: Tue Dec 04, 2007 3:55 pm Post subject:

how do we get the documentation for this board? i got my board yesterday and i want to start building it but have no docs...can we get the pdfs emailed to us?

thanks

Tronato · Posted: Tue Dec 04, 2007 4:31 pm Post subject:

Hello!

Het Loss1234, did you receive your new power supply?
Which one did you order?
Thanks!

TRON

Tim Servo

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I've been playing around with a panel design for the 566 VCO. I want to try and keep it at a 2U MOTM sized panel. With 7 knobs, 13 jacks, and a switch, that is nearly impossible but you can squeeze the jack spacing and make it fit. I'd rather have a more conventional spacing, so I eliminated the noise control and normalled the noise into the FM2 control. I figured it was unlikely to use noise and two FM inputs at the same time. This way you can use noise but over ride it with an external FM2 input. I also eliminated the noise output jack as I already have that function available in other modules. This simplifies it down to 6 knobs and 12 jacks that can fit in a standard 2U format as shown here. I plan on building the PCB and playing around with it to determine a final configuration.

Dave
Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

loss1234 · Posted: Sat Dec 08, 2007 4:18 pm Post subject:

did anyone get the docs for this yet? i want to make my 566 vco pcb but havent gotten any docs....

thanks

Tim Servo

Tim Servo

loss1234 · Posted: Sun Dec 09, 2007 2:09 pm Post subject:

yes please email any schematic or anything at all

i really want to get this going

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I've powered up my 566 VCO and have done some preliminary testing. I've put some photos and waveforms on my site at:

http://modularsynthesis.com/magicsmoke/566/566.htm

I also put a BOM on this page that I generated from the schematics. I chose my own capacitors and some do not fit on the PCB. I also used some of my own stock capacitors so I have not verified all the axial capacitors listed. Use the BOM for reference only.

I'm going to wire it up to some controls and jacks so I can play around and determine the usable range for both the VCO and LFO. I haven't yet decided if I want to build this as an additional VCO or perhaps instead as a super LFO.

Dave

Scott Stites · Posted: Sun Dec 16, 2007 4:01 pm Post subject:

That is some nice work!

frijitz

Thomas Henry · Posted: Mon Dec 17, 2007 12:15 pm Post subject:

Good advice from Ian there.

And by the way, the waveforms look pretty nice, Davebr. Thanks for posting them. The 566 typically looks a little sloppy below 300Hz, but even so it's still usable for music. I mean, even acoustic instruments change timbre at the low end, so why not our stuff?

Of course, if you're doing laser art or something, there's still no substitute like the CEM3340!

Thomas Henry

Tim Servo

"The noise output has a lot of crosstalk from the VCO. I have not been able to determine where the noise is coming from. The +15 volts has about 10 mV of noise at ~4X the output frequency. This noise pulses corresponds with spikes on the CV pin on the 566."

Here's a copy of some info I've shared with the ever-productive Dave Brown:

*************
I've looked at this and yes, it does look like C5 (noise source AC coupling) could be picking up some interference from U5 (the sub-octave divider). It could probably be rerouted, but I'm just questioning whether it would really be worth it. I added the separate noise output as an afterthought, as the noise gen is really just meant to be a mod source. It works nicely for that (and echoes the circuit shown in Thomas' 566 book), so I don't know if a new spin (that may or may not cure the problem) is worth it. I ran into the same problem when I had the VCO breadboarded, so moving a few components around may not help unless I completely reroute the board and keep everything but the triangle wave buffer away from the noise source. The main problem is: most noise sources aren't mounted right in the middle of a VCO Smile

******************

I may try a few mods to see if I can get rid of the bleed through. Beyond that however, I don't know if it's worth it just to gain an extra noise source.

Any thoughts?

Tim (yet another noise source) Servo

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I've disabled the 4013 by lifting D2. I also tried removing C5 and rewired it, although the trace is still present on the pcb. Neither had much impact.

I've cut the power runs to U4 and Q3. I've rerouted power to the remainder of the right side of the board. I've added series resistors and 4.7 uF caps at U4. It does diminish the cross talk, but not really enough to bother with. At 100R series resistors, U4 breaks into oscillation at various frequencies - that really makes noise. At 50R, it disminishes it a bit. The +15 volt series resistor does nothing. The -15 volt series resistor is the one that impacts the cross talk.

Dave

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I posted too soon! I put a 79L12 regulator in series with the -15V to U4/Q3 by simply replacing my 50R resistor. Quiet! Nice noise, and I cannot detect any cross talk. I have to connect one of the outputs to make sure the VCO is still in the audible range.

I'll clean it up and post some pictures.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I figured out I could edit my previous posts so I corrected the errors. I can't delete this post which was an update to the errors so I'll just edit it to this question.

Anyone know how to decipher the date code on a LM566CH? The only other code is 205. I'm guessing this is the 5th week of some year ending in 2, but what decade?

Dave

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

Here is how I eliminated the crosstalk from the noise output. It works fine for modulation with the crosstalk but I wanted to see if I could clean it up.

I isolated the -15 volts to Q3 and U4 and added a 79L12 regulator and 4.7 uF capacitor to filter this supply. I also isolated the +15 volt supply in a similar manner with a 22R resistor and 4.7 uF capacitor but you can leave this unmodified as +15 volts does not contribute to crosstalk. Here are photos of my modified PCB. I have simpler modification instructions on my website at:
http://modularsynthesis.com/magicsmoke/566/566.htm

Dave

Posted Image, might have been reduced in size. Click Image to view fullscreen.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I decided to build the 566 VCO in a "temporary" module using spare parts that I had. I used some scrap aluminum to make a panel and then glued a laser image to the surface. It came out pretty good. This way I can play with the module while deciding exactly what configuration I really want.

Photos and information at
http://modularsynthesis.com/magicsmoke/566/566.htm

Dave

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Tim Servo

Sheesh, Dave. Your "temporary" stuff looks better than my permanent stuff! Great work.

Tim (temporarily stuffed with pre-Christmas snacks) Servo

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

loss1234 · Posted: Sat Dec 29, 2007 6:23 pm Post subject:

id love an update on the documents for this. I am wondering how dave got his built, are there schematics available? i dont need a mouser parts list or anything (though it would be nice) but i would think there would be a schematic that the pcb was made from. Please try to hurry this along as i am sure there are people like myself who would love to get this built.

thanks

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

The schematics are mostly from the Making Music with the 566 book. Tim did change the ramp circuitry so it is different than the book.

I did publish my parts list on my page http://modularsynthesis.com/magicsmoke/566/566.htm . I chose my own capacitors and make no claims that these, or any of the parts, will match what Tim publishes. It is what I built my PCB mostly from as I had some parts already on hand.

I did make some part changes and listed these in the comments. This parts list can give you a feel for what the parts are but I cannot guarantee it is error free so use it at your own risk.

Changes include significantly lowering the LFO frequency, limiting the low range of the coarse control, and reducing the crosstalk from the noise output. Other changes are minor and are mostly personal preferences.

Dave