Sonic Reducer

4/23/2015

Here is my taken on the Analog Bit Crusher by Colin Raffel. It's a cool circuit that uses sample and hold to degrade the signal. I guess a more accurate description would be aliaser / sample rate reducer.

I replaced the oscillator with a better one that has a wider range and an additional pulse width control. I also added a much needed gate for the carrier oscillator - a envelope follower that turns off the oscillator when not playing. No more carrier bleedthrough. :)

The controls are:
Resolution - controls the pulse width of the oscillator. Wider pulses lets more clean signal through
Sample rate - control the frequency of the oscillator
Gate (trimmer) - this sets the gate threshold for the oscillator in relation to the input signal

I etched the enclosure for this one. I'm very happy with the result. :)
This tutorial is very good: http://diy-guitar-effects.tumblr.com/etching

The name and text on the enclosure comes from the lyrics from this song. But I bet you knew that already, otherwise - shame on you! :o)

PCB avaliable in the shop

sonic_reducer_vero.png
File Size:	150 kb
File Type:	png

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sonic_reducer_pcb.pdf
File Size:	184 kb
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35 Comments

nocentelli

4/25/2015 08:54:48 pm

Gate section is superb, would make a great retrofit daughterboard for all those terrible whiny heliotrope clones out there. Many thanks!

John

4/26/2015 11:27:15 am

I still get some whine when not playing. Any suggestions?

Fredrik Lyxzén link

4/26/2015 05:24:04 pm

Strange. Are you really using a LM324? It is crucial in this circuit.

4/27/2015 10:29:29 am

Yes. Maybe I'll swap it out for a different one.

Thorsten

6/18/2015 07:19:05 pm

I have the same issue with the whine. the thing is that when I tweak the trimmer there is either a no whine with no effect, or whine with the effect. I'll try to swap the LM and the TL around with some spares and see if that changes anything.

Mind you, it is way less whine than in the original bitcrusher so it is somewhat of an improvement. But it is still there and it also bleeds through when the bypass is enabled.

6/18/2015 08:24:27 pm

Try to use shielded wire for the pots and the input and outputs. It should help remove the whine. It's a very sensitive circuit... My vero didn't have the whine, but suffered from bleedthrough from the envelope follower gainstage. The dual layer PCB that i'm selling is dead quiet. So I think this circuit is not really suited for vero. :/ It lacks a proper ground plane which can be critical in some circuits.

8/16/2015 11:33:25 am

The demo simply sounds superb!! Just ordered the pcb after reading the discussion of the potential grounding issues with vero builds. Can't wait to build it!

Quick question about the gate trimmer: does the optimal setting depend on variable properties of the circuit's components, or on the input signal? (E.g. If adjustments are often needed for guitars with different pickups I would consider dedicating an external pot to the gate setting.)

8/16/2015 05:41:36 pm

Yes, the gate trimmer is set in relation to the input signal, so it might be a good idea to have it as an external pot if you are often switching between guitars. However, the input signal is boosted alot before the voltage follower so the difference of the trimmer may be very small between guitars. I'm not sure, since I have not tried it with different guitars.. it's best to experiment :)

Carsten

2/2/2016 03:49:20 am

Does the Sonic Reducer work well on Bassguitar ? Any experience ?

2/7/2016 05:49:09 am

Hi Carsten,
I have not used it with a bass. It should work fine on bass, but I don't know how well it would sound. / Fredrik

Gervaise

5/26/2016 01:59:06 pm

I'm unable to source a 2N5457 so I'm trying a J112, as per a recommendation elsewhere. I don't seem to be getting the effect I was hoping, certainly not as great as the demo video. Is it likely to be an incompatible transistor?

5/28/2016 11:23:21 am

Hi Gervaise,
I don't know if the J112 is a suitable replacement, but I guess almost any JFET would do. Just make sure that the pinout is correct. You may need to flip it around or even twist the legs. Check the pinout and compare it with the 2N5457. If it's still not working, maybe you have a faulty transistor or a problem somewhere else in the circuit

Julien Ribeill

6/13/2016 06:08:51 am

Hi every one !
Does somebody know , which is the sample rate?
50k or 500k?
Thanx

6/14/2016 01:53:45 am

If you look in the build document you will see that the sample rate pot is B500K. Cheers / Fredrik

McDylbot

12/17/2016 12:38:07 pm

Thank you for sharing your design for this one. Built one up last night and it works fantastically. Been after a good bit crusher type effect for a while. Kind regards Fredrik, keep up the great work!

12/20/2016 12:13:29 pm

Thank you. I'm glad you like it. :)
Cheers / Fredrik

Greg

1/3/2017 10:35:48 am

Hallo zusammen, habe gerade den SR fertig gebaut und leider den TL072 falsch herum eingebaut. Habe den Fehler leider erst nach dem Einschalten bemerkt, sofort Strom weg und den 72er gegen einen frischen ausgetauscht. Leider ist der Effekt nur seeeehr schwach, der Oscillator arbeitet aber das Audiosignal wird nicht gecrushed. Was könnte ich durch den gedrehten 72er noch geschossen haben? Fet? LM? Beste Grüße
Greg

1/3/2017 12:35:11 pm

Hi all, did the post above in German, sorry for that. Here the same in english...😉
Finished the SR and powered it up, but sadly with the tl072 in the wrong direction. I disconected power and changed the 072 for a fresh one.
The effect is very weak now, oscillator works, gate trimmer also works, but there is no really crushing going on, as seen in the video. What else could have been damaged with the 072 in the wrong direction? The LM? Or the fet?
Best regards
Greg

1/5/2017 07:36:59 am

Hi Greg,
Thanks for writing in english. I couldn't make any sense out of the google translated german text.. :P Hmm, since the oscillator seems to be working I suspect that it's the JFET that has gone bad. Try replacing it. If it still doesn't work, it could be a cold solderjoint somewhere. You could try reflowing the solder gently around the TL072 and FET. I hope that helps. Best regards / Fredrik

1/5/2017 08:06:10 am

Thanks Fredrik, I'll replace the fet then. I think I have some 2N5458 or 59 and some J201 in my box. Kind regards, Greg

Rich link

3/8/2017 09:09:37 am

I just built the stripboard layout, worked like a charm and massively exceeded my expectations -- very clean and quiet with that pristine quality you only usually get from high-end bit crushers. Thanks so much for sharing this.

3/9/2017 02:49:45 am

Hi Rich,
I'm glad you like it :)
Cheers / Fredrik

Andrew Diamond

5/9/2018 04:42:25 pm

Just finished building Sonic Reducer. Works perfect!!! Used TL062. FET is soviet 2P303A (2П303А), that gives a bit more crystal sound. i've used 200k pot for Resolution.
No more whine! Thanks alot!!!

5/21/2018 02:29:16 am

Hi Andrew, Thank you for the build report. I'm glad that it's working great! :)

Nicola

7/8/2018 10:37:17 pm

Hi Fredrick , I made your bit crusher and it works great! But now I would like to implement .. I want to put it in a container along with another effect, such as distortion, and with a switch spdt can select the type of effect, but the signal coming out of the bit crusher is much lower than the other . I was thinking of inserting a pre-amp stage just for the bitcrusher, what would you recommend?
Thank you very much!

Dave Benning

12/21/2018 11:51:25 am

I just recently finished building this from the kit. (v.2) I like it, and deeply enjoyed the build, but I can't seem to really get it to sound as intense as the one in the demo video above. Is that pedal built on a different circuit, or did I mess something up?

1/4/2019 03:13:35 am

The 2.0 should be even more intense than the first version that is in the demo. Make sure that your Sample Rate pot is a 1M, and that C5 is a 22nF cap.

1/4/2019 08:29:52 am

Thanks for the advice, I’ll take another look later today.

Daniel link

2/21/2019 04:36:26 am

Hi, I just built this one and I'm getting no troublesome oscillation whatsoever. So I don't really know what to set the trimmer to. ^^ Did I do something wrong/right?

(It sounds like in the demo though. Pretty happy with it.)

3/12/2019 03:11:41 am

I'm glad you are happy with it. Sounds like you did everything right. :) The trimmer position isn't that important. Cheers / Fredrik

Daniel

3/12/2019 01:05:19 pm

Yeah, I'm loving it. With this thing I can pretend to be Disasterpeace for hours on end. :D

Suprasimon

2/3/2020 06:58:20 am

Hey! I'm planning to build this baby up. I searched the whole day for a DIY Sample Rate Reducer. I heard there is a v2 out with less whine. Is it possible to get that schematic too or is it the same schmeatic and just the parts did change? If so, which parts did change?
Thanks in advance! :-)

Erin

2/29/2020 08:27:18 pm

Hey...I'm in process of building this...Do you have a wiring diagram of how the pots are hooked up? I'm using the vero board layout. Thanks.

2/29/2020 08:30:29 pm

Ooh....I figured it out!

Sérgio

5/18/2021 02:58:29 pm

Hi Fredrik!
I just finish this pedal today! Is this meant to be used in front of an amp or in the effects loop?
Just order the Sentient Machine from Musikding and still getting more experience to be able to build the Multiwave mega! Thanks for your pedals!

Best regards!

Sonic Reducer

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