S/H => bitcrusher-style

bugbrand · Posted: Wed May 03, 2006 6:48 am Post subject: S/H => bitcrusher-style

A sample&hold should work fine as a sample-rate-destroyer, right?
(I was thinking bit-crusher, but that's bit depth whereas this is sample rate)

I was thinking to make use of the AD781s I got from Analog.com -- they're 8pin dip Sample & Hold amplifiers... Should be as simple as making a variable speed pulse-osc ranging from 44.1k down to ... low..?..(plus, of course, preamping etc)

Or am I being wrong?

***EDIT***

Read through this thread for details on the AD781 based Audio Sample Rate Reducer design - the BugCrusher

There are two schematics hosted on electro-music on this thread:::
http://electro-music.com/forum/topic-13444.html

mosc · Posted: Wed May 03, 2006 8:56 am Post subject:

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bugbrand · Posted: Thu May 04, 2006 2:33 am Post subject:

Hey Howard that sounds ACE! Yes, super simple..

BUT! I tried out with the AD781 yesterday and I got masses of signal bleed from the sample-trigger signal..

The 781 requires very few extra parts so breadboarding was easy - fed a function gen in but you require very short pulse signals, so I added a pulse converter with two 40106 gates.. Lots of bleed through. argh, so I tried making another of the 40106 gates into the osc (thought this may help..) - still loads of bleed through (..the sample-trigger signal needs to be 0-5v whereas the rest runs at +/- 12v)

The sounds, apart from the bleed through, were really gnarly and good.. May make a good lofi effect.

I'll try some more ideas out today..

DARN - and I REALLY need to get my MicroModular back again (..its currently been sitting in london for a few months..)

mosc · Posted: Thu May 04, 2006 5:36 am Post subject:

Yes, the 781 seems to be a little bit different than the NM S/H module in that it is not edge triggered.

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.

Maybe if you clock it with a square wave oscilator with a adjustable pulse width you'd get good results.

bugbrand · Posted: Thu May 04, 2006 6:21 am Post subject:

YES - more findings = things sound good!

You're right Howard - the problem was with the non-edge triggering. I'd kind of figured that yesterday - 'cos it was working like a sqr-wave trem at low rates.

Well, I adjusted some things and found that its very simple to make something pretty darn ace - and the bleedthrough is almost gone by making the Sample trigger pulse really narrow (it could probably go even narrower..)

So, I did a quick schematic (which shows just how simple it is..):
Proto RateReducer Schematic

And uploaded a couple of quick demo sounds of a 505 and a guitar going through it (..this was using a modular preamp to boost the signals first and then going out through modular mixer - so treating this circuit as a new processing module.)
505 and guitar
guitar hits - good drum sounds?

bugbrand · Posted: Thu May 04, 2006 6:21 am Post subject:

These chips are available as free samples from analog.com too..!..

mosc · Posted: Thu May 04, 2006 7:30 am Post subject:

Sounds good. A certain amount of bleed through is to be expected with this kind of circuit.

Nice cheap narrow pulse oscillator you have built, BTW...

bugbrand · Posted: Fri May 05, 2006 1:28 am Post subject:

dnny · Posted: Fri May 05, 2006 4:51 am Post subject:

very nice samples from both.
i placed a sample order from analog.com, so this is soon under my soldering iron

piedwagtail · Posted: Fri May 05, 2006 9:09 am Post subject:

Good work Tom,
Any reason i can't do this with the LF398?,i have a stash of early cans.....

being not so needy of the ultra-scramble Smile

putting a LDR around the 1M pot might be feasible for mild changes.(empirically parallel or series)
and a LDR/vactrol vc-mixer to vary the clean to scramble mix.

Is Farnell,via Newark,the only way to get vactrols over here?
The £12.95 postage is pain for $1 devices....

Robert

dnny · Posted: Sat May 06, 2006 1:20 am Post subject:

piedwagtail · Posted: Sat May 06, 2006 6:19 am Post subject:

Takeda reverse viewing roundhouse.... Wink

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Uncle Krunkus · Posted: Sat May 06, 2006 7:23 am Post subject:

I love those samples!
Well done.

toppobrillo · Posted: Sat May 06, 2006 9:17 am Post subject:

sounds good!

bugbrand · Posted: Sun May 07, 2006 4:00 am Post subject:

Cheers.
I fully intended to try out the VC rate control idea yesterday,
But then I got a Modular G2 Rack.. so I didn't have any time left over (not surprising really - the G2 is freaking amazing. Really, I don't know any system that comes close to its wonders)

But I will try to investigate tonight -> G2 or not, still got to make more synth modules..

dnny · Posted: Sun May 07, 2006 11:40 am Post subject:

mosc · Posted: Sun May 07, 2006 12:22 pm Post subject:

Congrats on the G2...

IMHO, the G2 makes a superb platform for debugging ideas for DIY circuits.

toppobrillo · Posted: Sun May 07, 2006 7:24 pm Post subject:

yes, definitely, i have been using the demo and though my PC will only allow me to run about 8 modules or so, [yeah its pretty slow] i have been able to experiment instantly with ideas that i wouldn't otherwise or would have taken hours to breadboard and test.[not to mention tearing down whats already breadboarded.] so yep tell your friends about it. free sound circuit prototyping software.

bugbrand · Posted: Mon May 08, 2006 1:39 am Post subject:

piedwagtail · Posted: Mon May 08, 2006 7:11 am Post subject:

Tom,

LF398:I'll have to do my homework,i've used them in Grenader S/Hs without difficulty.
I'm knee deep in oscillators at the moment,so i'll wait to hear your forthcoming voltage controlled samples Razz

If you're up to London,i can add another rack:a 4.5U sub frame,used to be a Wayne Kerr ballistics analogue computer.Fits a 19" and has 5 plug in cards.(Don't think i'll fit it in my lifetime achievement schedule Rolling Eyes

)

Robert

Uncle Krunkus · Posted: Tue May 09, 2006 1:34 am Post subject:

"Wayne Kerr"!!?? Shocked

That's got to be a joke right? Laughing

piedwagtail · Posted: Tue May 09, 2006 7:13 am Post subject:

The build quality is formidable....http://www.waynekerrusa.com/
http://www.waynekerrtest.com/

Uncle Krunkus · Posted: Tue May 09, 2006 7:26 am Post subject:

Looks like a fine company.
It's just an unfortunate name.

elektro80 · Posted: Tue May 09, 2006 7:29 am Post subject:

Uncle, I know what you mean. Laughing

elektro80 · Posted: Tue May 09, 2006 7:31 am Post subject:

However, that hardware looks like some serious shit!

wave