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:

s-h.mp3

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Sounds like this

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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

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