Dimension C Build Report

moosapotamus · February 21, 2005, 03:27:03 PM

Other than, "This thread is freaqin' awesome!" all I have to add is...
Here's a very nicely retouched DC-2 scheme...
http://sapphia.s10.xrea.com/cgi-bin/img-box/img20050212012045.gif

~ Charlie

StephenGiles · February 21, 2005, 03:31:49 PM

Just got in from putting down salt & grit on the downward slope at the end of our road! Nobody else bothers - they're all stuck in front of their TVs. We're expecting our 1" of snow overnight!

Ton, do you have a link for espace (English) at the search page, where you can enter the patent number? My link no longer works for some reason.
Thanks
Stephen

puretube · February 21, 2005, 04:06:10 PM

information lost...

DiyFreaque · February 21, 2005, 04:28:05 PM

Thanks for that link, Charlie! It took me forever to get all the correct ref des's figured out on the copy I had. Whoever touched that up did a nice job.

One thing, though: anyone considering building the Dimension C - remove that link from between pins 9 and 10 of IC2. When I first breadboarded the Dim C, it would go *skrrrraaaaank* if any note of any volume was put through it. I was convinced I had all the connections correct, and I did - that was the problem. Mike Irwin pointed me in the right direction, and I pulled the little bit of wire connecting those two pins - it sang like a bird after that.

Cheers,
Scott

StephenGiles · February 21, 2005, 04:33:31 PM

Thanks Ton. Just 1" of snow in England and there is traffic chaos! Every year is the same!

The Dimension C project looks very good, I'm thinking about it.
Stephen

puretube · February 21, 2005, 04:38:42 PM

information lost...

puretube · February 21, 2005, 04:57:06 PM

information lost...

StephenGiles · February 22, 2005, 01:53:01 PM

Thanks for the link Ton - we had a snowfall overnight, but it's nearly all gone now!
Stephen

puretube · February 22, 2005, 03:29:14 PM

information lost...

DiyFreaque · February 28, 2005, 01:11:01 PM

Well, this weekend I wired up the first set of boards and put them through their paces. I'm happy to announce that the boards for S/N 001 work exactly as planned (and it sounds great, too!). The testing for the last of this extremely limited edition of 2 Dim C's (S/N 002) will have to wait a couple of weeks - I'm going out of town on a biz trip =-(.

All in all, things went very well - I found one mistake on the main board (the timing cap for the right channel compressor did not connect to ground - no link to the ground bus was put in), so the first time I tested the audio, it sounded pretty horrendous. But, after putting in the link, it sounds great!!

Testing is a slow process - I first apply power to the main board and test the +9V, +4.5 and ground routings. Then I hook up the Delay 1 board, test that the +7V and 3.5V reference are good and going to the right places. Then I do the same for the Delay 2 and Control board. Then I put in all the board interconnections (including coaxial cable for the audio jumps from the main board to the delay boards and back), put in the IC for the LFO, make sure it's working, then I put in the chips and go for broke. It takes a lot of temporary testpoint wires and connections because there's no front panel to hook up (they're on their way).

2 Weeks....sheesh.

Cheers,
Scott

puretube · March 01, 2005, 02:53:59 AM

information lost...

puretube · March 04, 2005, 04:32:45 AM

Sir Giles:

correction to above proposal:
don`t swap "de" for "gb", but for: "en"....

try it right now! it`s back on air!

StephenGiles · March 04, 2005, 08:57:48 AM

Thanks Ton, that's great!
Stephen

DiyFreaque · March 26, 2005, 01:39:46 PM

Getting down to the short rows with the Dim C project. Both sets of boards are interconnected, tested and calibrated. All parts for the racks are in, and Jeff is starting up putting them together. He says the Schaeffer panels look really nice! I'm going to send the boards to him (schedules don't allow the assembly party) and he's going to do the final construction, which involves mounting the boards in the rack enclosure and wiring up the controls. I've written up detailed wiring diagrams for him (9 pages of illustrations!), and I'm going to install coded/labeled wires to the boards before shipping them to him. Each set of boards needs 34 wires installed for connection to the front panel (5 of them are coaxial cables).

Finishing off the second set of boards, I recorded it doing two things the original Dimension C did not do: Processing a stereo input and modulating the delay lines with a fast pulse.

Both left and right outputs of my Korg DW6000 are patched to the Dim C stereo inputs, and the left and right outputs are going straight to the recorder (no other effects are used in the chain). A pulse LFO is patched into the CV input of the Dim C.

The sample starts out with the chorus of the DW6000 off, which is a mono signal, so the beginning is in mono. At the beginning the Dim C is also bypassed. At 00:21 I switch the on-board chorus of the DW6000 on, converting it to a stereo signal. At 00:38, I un-bypass the Dim C. After that, as the sample progresses, I use the Dim C's CV Level pot to increase the level of CV for a while, then towards the end I back it off, lowering the level of CV. The end result is a stereo signal being sharply modulated in stereo at varying intensity.

http://mypeoplepc.com/members/scottnoanh/sitebuildercontent/sitebuilderfiles/dimc_dw6k_pulse.mp3

I like the stereo effect of modulating the Dim C - modulating it with a faster triangle than the internal LFO results in some really nice stereo Leslie type effects. Modulating it with a slow random voltage creates some very interesting stereo modulation.

Cheers,
Scott

puretube · March 26, 2005, 01:49:18 PM

arrgh - you Freaque with your soundclips!!!

need an iAMP for this silent PC urgently...

DiyFreaque · March 26, 2005, 02:17:51 PM

Hey Ton,

Sorry about that!

Forgot to mention that sample is 2MB. I'm on dial-up, so I know how crucial that info is...

Oh, Ton, I also keep forgetting to mention, your previous signature line 'Ad Aspera Per Astra' is the motto of my home state (Kansas) here in the USA. Only here it's written as 'Ad Astra Per Aspera'. I always thought it would be a cool title for a Kansas album, but apparently they didn't.

Well, better start installing wires...I want this thing done.

Take care,
Scott

puretube · March 26, 2005, 04:56:58 PM

information lost...

moosapotamus · March 27, 2005, 03:15:15 AM

Wow! That sounds great, Scott! Nice work!

~ Charlie

DiyFreaque · March 27, 2005, 11:36:03 AM

Thanks Charlie! I figured it would be nice to post a sample of the thing doing something other than the nice, lush modulation the Dim C is famous for.

Still working on getting the things ready for final assembly - hit a minor snag yesterday:

I decided to check out the Dim C's one more time, because once the wires are installed, I won't be able to test them until they're installed in the racks. I went through all the functions and thought of one thing I hadn't double-checked - a pulse LFO being able to modulate the Bypass function. On the Dim C (ie my version), the bypass input is designed to toggle on a +5V trigger from a keyboard or sequencer or EG, and also to be used as a sort of modulation option using a pulse LFO. It had worked before, and still reliably triggered off of my keyboard trigger, but I plugged a square wave LFO into it and....nothing. That particular LFO is a fixed square LFO, so I plugged it into one of my LFO's that has variable pulsewidth - that worked. I thought, well dang, it has to be a narrow pulse, and widened the pulse width on the LFO to see if it would stop working. It worked throughout the range. I looked at both of the LFO's on the oscope, and they looked identical, but one would trigger the bypass and the other would not.

I messed with it for quite a while, and finally I ran the non-working LFO through a VCA to give it a bit of gain, and then it worked. I looked more closely at the levels between the two LFO's and realized that the one that worked was a hair higher in amplitude than the one that did not - I hadn't adequately tested what *level* the bypass would trigger at, and when I did, the LFO that worked barely hit that level and the other barely fell short!!!! That would have really hosed Jeff had he tried it with his LFO's, because I imagine they're probably close to 10Vp-p (the one I was using is a bit stiffer at around 10.5Vp-p), and they probably wouldn't have had the oomph to trigger the thing. Even his keyboard or sequencer trigger may have been a toss-up in terms of functionality. To have a circuit that requires such a choosey level to trigger is unacceptable to me, and would generally be one big pain in the ass.

So, I whipped together a trigger booster on breadboard, interfaced that to the Dim C, and it worked flawlessy at levels much less than +5V or greater than +5V. The bypass switch circuit still works, too. I found a place on the delay 2 board to fit it, so I've installed and tested it on one Dim C and am about to do the same with the second Dim C.

(Sigh) Onward...

Cheers,
Scott

inverseroom · March 27, 2005, 08:16:45 PM

WOW. That clip is just beautiful. I should never have sold my C, though I know it never sounded like that...

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Dimension C Build Report