Roland - AS-1 Sustainer  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
analogguru
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Post by analogguru »

People like guts? ok, here are some others from our japanese hackerfriends (click on the pictures for high resolution):
enjoy,
analogguru
as-1a.jpg
as-1a.jpg (20.43 KiB) Viewed 798 times
as-1.jpg
as-1.jpg (19.63 KiB) Viewed 798 times
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magikker
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Post by magikker »

Haha... Well long story short, I am trying to design an effect... I want to build a reverse noise gate... Basically if the volume gets above a certain level it will cut the signal out, until the level is reduced below the set threshold.

I want to build this to put it into a passive feedback loop with a delay pedal... I am thinking that this would allow me to let the delay rampage out of control but have it stay with in a reasonable volume. Plus It ought to give me some interesting stuttering sounds...

Since to the best of my knowledge no body has built the reverse noise gate, I've been looking into ways to do this myself. People have suggested looking into Envelope Followers, Digital Switches, and OTA's to accomplish my goal. So I've been reading up on those... I guess my first question would be where to go to read up on OTA's because they make the least sense to me at the moment. And I'm sure as I read I'll have about a hundred more questions.

I haven't said anything here since I didn't want to bog you guys down with any silly questions...

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Post by grolschie »

DIY thread's been moved to the Off Topic lounge now.

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invictus
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Post by invictus »

magikker wrote:Haha... Well long story short, I am trying to design an effect... I want to build a reverse noise gate... Basically if the volume gets above a certain level it will cut the signal out, until the level is reduced below the set threshold.

I want to build this to put it into a passive feedback loop with a delay pedal... I am thinking that this would allow me to let the delay rampage out of control but have it stay with in a reasonable volume. Plus It ought to give me some interesting stuttering sounds...

Since to the best of my knowledge no body has built the reverse noise gate, I've been looking into ways to do this myself. People have suggested looking into Envelope Followers, Digital Switches, and OTA's to accomplish my goal. So I've been reading up on those... I guess my first question would be where to go to read up on OTA's because they make the least sense to me at the moment. And I'm sure as I read I'll have about a hundred more questions.

I haven't said anything here since I didn't want to bog you guys down with any silly questions...
someone please correct me if im wrong, but if you want to "cut" the signal out, the solution could be as simple as diode and FET switching. optoisolators might also be useful.. DEPENDING on the threshold level you're planning.
"im the master of my fate, im the captain of my soul... " -invictus

magikker
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Post by magikker »

invictus wrote: someone please correct me if im wrong, but if you want to "cut" the signal out, the solution could be as simple as diode and FET switching. optoisolators might also be useful.. DEPENDING on the threshold level you're planning.
Yeah... That's how I think about this... Right now I have page of ideas as to how it might work... but no really solid grasp on a great way to pull it off... I'd also hate to be the guy to derail this thread too much, so feel free to ignore my little side project....


Yeah... That thread is off topic I guess... When it is moved to debatable you know it is in the "uncomfortable zone"

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Post by seniorLoco »

Rolland AS-! :D

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Post by seniorLoco »

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Last edited by seniorLoco on 30 Nov 2007, 10:31, edited 1 time in total.

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Post by seniorLoco »

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Last edited by seniorLoco on 30 Nov 2007, 10:32, edited 1 time in total.

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Post by sosodef »

I bet baja has some tricks. We need a baja version :)

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Post by bajaman »

Hi senior loco and sosodef
thanks for the pictures - I will draw up a pcb and layout - I may have the schematic in my archives - if not I will have very soon :lol: :lol:
bajaman

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Post by sosodef »

Baja is the best. I always look forward to seeing his posts. I never played the boss sustainer. It should be interesting.

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Post by bajaman »

AS1e posted twice - no AS1f :?:
As1l posted twice is there another pic - AS1m???
cheers
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Post by analogguru »

Schematic is an "old dog" and can be found here:

http://www.geofex.com/FX_images/rolandsu.gif

Inaccurate is the switching: In original the AS-1 doesn´t have true bypass.
The rest seems to be ok, even when the 1µF in series with the LDR made me a little bit nervous (since this will cause "compression dependent frequency response"). But it is really only a 1µF.

Transistors on this unit are 2SC 1681-GR for Q1/Q2 and 2SC 372-Y for Q3/Q4.

What I am wondering is who stole from whom:
Roland from Colorsound or Colorsound from Roland ?
http://www.freeinfosociety.com/electron ... php?id=315

analogguru
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Post by sosodef »

are these sustainers working like compressors or is it a different beast?

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Post by seniorLoco »

ooopppss :oops: sorry baja ...its the early friday morning bug !!!

edited and corrected ...thanks 8)

It's a good sustain pedal ...the best i have tried but the compression a wee bit quirky tho. maybe the aging components.
Does not paly well in front of FF type :roll: kinda auto cleans up evertime you pluck ....but the sustain in front of a muff type is mind blowing :twisted:

Can be improved fellas ....

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Post by bajaman »

Have you tried it after a fuzz face :?:
bajaman

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Post by sosodef »

interesting my post above looks like I actually know something :shock:













somehow AG's post is in my name :shock:




Cool so its a great sustain pedal. I love that. It would be nice if it could actually compress nicely as well. The idea of a great sustain that compresses poorly sounds like it was half assed.
Last edited by sosodef on 30 Nov 2007, 11:19, edited 1 time in total.

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Post by bajaman »

I would think that Roland (used to be Acetone) were "inspired" by Colorsound, just like Electro Harmonix with their Big Mush pie :wink:
Does that make Roland Corp the original Bootweakers AG :lol: :?:
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Post by bajaman »

.....or was Mike Matthews the first booteeker :roll:

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Post by analogguru »

sosodef wrote:interesting my post above looks like I actually know something :shock:

somehow AG's post is in my name :shock:

Cool so its a great sustain pedal. I love that. It would be nice if it could actually compress nicely as well. The idea of a great sustain that compresses poorly sounds like it was half assed.
So, to avoid confusions the mentioned post has been corrected, the answer is folloeing here:
are these sustainers working like compressors or is it a different beast?
Q1/Q2 are acting as a 2-stage amplifier. The gain is set by the feedback loop from collector of Q2 to the emitter of Q1 (You could place a potentiometer [50k] there too).

If the output signal increases the LED is lighting brighter thus the resistance of the LDR decreasing which causes a gain-reduction.

BTW, moany LDR´s are most sensitive at yellow (and not red) light.

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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