The Karplus Strong eChucK DIY Project

rosch · Joined: Oct 03, 2009 Posts: 165 Location: germany

i have a question regarding the zener diodes. in the bom they're called Zen-4V7
does it mean they're for 4,7V (just like in resistor names)?
like these:
http://www.banzaimusic.com/4-7V-Zener-Diode-0-5W.html

Inventor · Posted: Sun May 16, 2010 5:18 am Post subject:

rosch · Joined: Oct 03, 2009 Posts: 165 Location: germany

thanks! i'll have everything in stock when these become available!

Inventor · Posted: Tue May 25, 2010 7:38 pm Post subject:

jmejia · Joined: Mar 12, 2009 Posts: 114 Location: portland

wow awesome! i'm a total latecomer to this thread - but it's looking good!

Inventor · Posted: Fri Jun 04, 2010 11:26 pm Post subject:

Cool, welcome to the thread. I heard from Jeff today. He has received the 50 boards and they look good. I will receive them in a mail sometime in the next week or so.

Les

jmejia · Joined: Mar 12, 2009 Posts: 114 Location: portland

just finished reading through the thread and getting myself up to speed on your project! pumped on it!

does your clocking VCO have enough range to get into slower delay times as well? (not for KS - but it seems like it should work well as a standard VC-delay as well - if your VCO has the range?)

Inventor · Posted: Tue Jun 08, 2010 2:01 am Post subject:

You know, I'm just winging this one, but if i recall correctly, the VCO covers more than the full range of the BBD.

Les

jmejia · Joined: Mar 12, 2009 Posts: 114 Location: portland

sweet! i'm pumped!

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

Hey! My parts arrived from Digikey today (have I ever mentioned how amazed I am at how fast their shipping is?). If all goes well, I'll have at least one fully populated KS11 board ready to play with! Hmmm, I suppose I ought to gather up all the other stuff I need to drive it...

Hey Les, what's the fastest way to get sounds out of this board?

Inventor · Posted: Wed Jun 09, 2010 4:00 am Post subject:

jeff-o, the fastest way to get sounds out of this board is to breadboard a sequencer and drive the inputs with it. You can, for example, use a 4060 binary counter and put a resistor in series with each of the outputs (100k Ohm), tie the resistors together and connect that to the VCO and VCF inputs. Then connect a 0.1uF cap to that same summing node and hook the other end to the stim input. This is the minimal one-chip boolean sequencer circuit that I used on one of Mathe's two boards.

Sounds like you'll be the first one with a KS11 working, so more power to ya Jeff! Good luck with the build and have fun.

Les

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

OK, I'll see if I've got a 4060 kicking around somewhere.

If I want to trigger single "plucks" on the board (say, to simulate a guitar string being plucked) I assume I can just connect the VCO and VCF to a set analog voltage, and pulse the stim input?

Inventor · Posted: Wed Jun 09, 2010 8:21 am Post subject:

Yes Jeff, use pulse widths of 1ms to 10 ms if you do that.

Les

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

OK, I'll hook up a one-shot to generate a pulse. Is there a preferred number, or is 1 to 10 mS just an acceptable range? Does the length of the pulse affect anything?

Inventor · Posted: Thu Jun 10, 2010 4:39 am Post subject:

Yes Jeff, the pulse duration affects the sound. In my experiments I found that 1 to 3 ms makes the best sounds. By the way I got some BBD chips yesterday and tested the MN3208. It makes great bass sounds, in fact too deep of a bass at the slower VCO settings. So you should have a good bass guitar sound for your laser guitar project!

Les

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

OK, I'll aim for a pulse duration in that range.

MN3208, eh? I've got 3204s and 3209s right now. I'll have to order up some 3207s and 3208s as well.

I haven't actually finished my KS11 build just yet; last night I was out acquiring a nice donor guitar for my next project. It's actually a 6-string electric, but it should work just fine. I'll still only be able to fit four "strings" on it though, due to space and playability reasons.

Inventor · Posted: Mon Jun 14, 2010 5:32 pm Post subject:

Hey folks, I've received the boards from Jeff and I'll be mailing them out to anyone who pays for them. I feel that it would be best to wait for Jeff and myself to build test boards first though. That way in the event that there is a cut trace or jumper wire or some other issue, we will be aware of it and can inform you accordingly.

So for now I will take advance orders by paypal for boards. Unlike the first run, we have about 46 boards left to mail out so some who wanted multiple boards should get them now. And good news: the price is cheaper! A lot cheaper actually: only $12 each plus $3 shipping to anywhere, so a total cost of $15 per board. They're cheaper because we had so many made, obviously.

Also, if you ordered a bare board (not a built one) from the first run, I will send you a free board from this second run. I'm doing that because there were silkscreen errors that made the build really difficult and all the confusion probably was a bit of a bummer for some. So just keep your first run board as a memento and expect a free board in the mail soon.

To order KS boards, please send $15 each via paypal to lester.hall@comcast.net

I will keep records of the purchases and mail out the boards in a few weeks or so. If you are sending paypal in non-US dollars, there is an exchange rate that applies so please add an extra dollar or so to cover that. Or maybe paypal lets you specify a received price, I don't know. I'm just saying that some folks send me less cash than intended due to the exchange fee, to please try to compensate for that somehow.

Also please note that the $3 shipping is the same for international and for US orders. I finally figured out the right way to send these things - in padded envelopes via the US post office's least expensive service. I also realize now that I can't be going to the post office every few days with another onsie twosie of circuit boards because of time, gas, ans hassle, so please allow a few weeks for delivery as I collect the orders and put them together into one or two large mailings.

Thanks in advance for your orders and for your support on this project, it's been plenty of fun so far!

Les

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

Well everyone, I have great news! I finally hooked up a basic setup to test the KS11 board. And, as expected, it works!

I set up a 555 timer as a "one-shot" pulse generator, that produces a 3ms pulse each time a button is pressed. The output goes straight to a set of headphones. I tested it with both an mn3204 and mn3209, both work well (as a side note, very similar, too). I've got 3207 and 3208 chips coming to try out as well.

Ah, what a fun little circuit! Love it! I'm looking forward to putting it to work in my next project...

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada

Scratch that bit about the 3204 and 3209 being almost the same. They're not, I just had to adjust the feedback a bit. Learning curve and all that...

Inventor · Posted: Tue Jun 15, 2010 10:39 pm Post subject:

Jeff, that is excellent news! Now I feel good about sending out the boards sooner than later. You won't have to wait for me to order parts and build a board for test cause Jeff already did it! Yay \o/ !!!

Les

Sound · Joined: Jun 06, 2006 Posts: 842 Audio files: 1

Ordered

Inventor · Posted: Wed Jun 16, 2010 1:58 am Post subject:

jeff-o · Joined: Jul 19, 2009 Posts: 97 Location: Ontario, Canada