An Analog Synthesizer for the 21st Century

Scott Stites · Posted: Mon Aug 13, 2007 6:39 am Post subject:

Woo hoo!!! Congrats Magic Smoke!

The Alison Project · Posted: Mon Aug 13, 2007 7:18 am Post subject:

Ordered paperback version, must admit I almost took the PDF version cause I want to see this crazy LFO...

Trumpet1 · Joined: Aug 02, 2007 Posts: 10 Location: Long Beach, CA

Wow. I'm a forum member for less than 2 weeks, and it provides a major addition to my hobby. I just ordered the book from Lulu. I wonder what she is like.

I hope it provides enough info so I can run my digital model trains from the synth - you know, the train moves in accordance with the envelope of the music, or maybe I can use the sequencer to program stops at various stations.

Anyone believing this?

-Trumpet

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

On page 16 (the VCF), it says "Repeat (...) R32". That should probably be R30, the pot.

On page 17 the same thing happens with R38 and R30 (should probably be R36 and R28).

Tim Servo

Thomas Henry · Posted: Thu Aug 16, 2007 2:13 pm Post subject:

Oops!

Sorry for the confusion. I actually number the components by hand (no automation) so that they increase in value numerically. This implies that I proofread the schems by hand too, using colored pens and so forth. These designs occurred over the course of three years, and were proofed many times, but obviously a few screw-ups slipped through when I optimized some values. Thanks for keeping me honest!

I will confess that more than one cocktail was quaffed during the design and proofreading stages...

Thomas Henry

EdisonRex · Posted: Thu Aug 16, 2007 3:18 pm Post subject:

Just bought and downloaded the PDF, printed it double sided so I can bind it at work. You know, porn isn't anywhere near as good as this. Laughing

I wish there had been a bit more discussion on how the circuits worked though. I can follow, but I've been reading stuff like this for yonks. Just saying it might be nice. I like to read descriptions... Razz

RF · Posted: Fri Aug 24, 2007 5:47 am Post subject:

Just got my printed version in the mail.
Very nicely done - Thanks Tim and Thomas!

bruce

Tim Servo

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

Got mine in the (snail)mail today!

Looking very good. Hmmm...anybody working on layouts for the VCA?

That ADSR looks mighty similar to the "old" TH env. Any differences/improvements over the old one?

Oh, and sure hope we get pcb's for that LFO from magsmoke...

Hooray!

C

Tim Servo

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

I am having a great time working on layouts for the deisgns in the book. So glad I went the PDF route, plenty of copies to vandalize. I would say the LFO would be the best candidate for a board, although I really wanna try it on the breadboard, and see how to get all of the waveshapes simultaneously.

Already have 3 XRs done, and layouts for the LM VCO, the S&H on tiny perfboard (its too simple for a PCB I think), and working on boards with a pair of ADSRs, and also a double VCA. I cant stand the thought of orphaning half of a pricey chip like the SSM2164. Hopefully Ill have all of them done by the end of the month and can build some stuff when time allows, between Klees, wogglebugs, QFGs, and on and on and on...

23isgood · Posted: Sat Aug 25, 2007 5:02 pm Post subject:

Do the LFO for sure! Its fairly complex, so a PCB would be very nice.

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

Photon

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

As the musician said..."I want it ALL".

THeff · Posted: Tue Sep 04, 2007 8:31 pm Post subject: ASF21 LFO

Hi Thomas, Tim, and John,

I just finished building the 8038 LFO (or Super LFO!) from your new book and I thought I would share a picture and some of the performance numbers.

Here's some quick numbers:

Freq Range: 9 Secs - 235 Hz With CV range of -7.95V to +5.80V
Current: 70mA positive, 40mA negative.

I think I am going to put some series resistors on each end of the Coarse Freq pot to limit it's voltage range. I did notice that above +5.80V the high end frequency does not change, and below -7.95V on the low end it stops oscillating. I have not tried to set the 1V/oct trimpot, I just left it centered. I am very pleased with the performance and will be making a front panel soon.

Regards,

Tim

Thomas Henry · Posted: Tue Sep 04, 2007 9:12 pm Post subject:

Good job!

Feel free to limit the range, but as I've mentioned elsewhere I put the large span in the Coarse pot on purpose. When summing various signals (keyboard, envelope, external LFO, foot pedal, etc.) it is possible to clip the control or wham into one of the rails. The big range (which is straight from Electronotes designs) is to ensure that no matter what you're using as a control input, you can always center things appropriately. Positive CV, negative CV or even no CV at all---it makes no difference---you can always pull the unit into a useable range.

It's kind of a big circuit, isn't it? I can't believe you had the patience to do it by hand!

Thomas Henry

THeff · Posted: Tue Sep 04, 2007 10:08 pm Post subject: 8038 LFO

Hi Thomas,

Thanks for the reply.

v-un-v

TheAncientOne · Joined: Dec 26, 2006 Posts: 144 Location: United Kingdom

Got it in PDF myself - with my failing eyesight, it's good to be able to print the larger diagrams out onto A3 pages. Whoo-hoo Foldouts! (well this is pure synth engineer porn after all!).

I'm just going perfboard myself for now.

Keysandslots · Posted: Wed Sep 05, 2007 5:52 am Post subject:

I paid for the download version but didn't get to do the download. I'm at work and used my home email address, I'm hoping they've sent me a link.

Randy

v-un-v

Scott Stites · Posted: Wed Sep 05, 2007 6:30 am Post subject:

Tim strikes again with his perfboard wizardry! That LFO is one of my favorite TH circuits of all time. He put a lot of options in there to make it a really expressive, versatile little LFO. It's one of the circuits I wish I would have left on the breadboard longer - I recall I had some project that required the BB room, and I removed the circuit to put that on - don't recall the project that replaced it, but I sure remember what it replaced!

I never did a press'n'peel of the XR-VCO (or any circuit for that matter). There's a layout Thomas did for it on my site, and another one Tom Bugs did on the Bugbrand site.

Cheers,
Scott