Subspace Transmission - A fuzz with a recording and playback

Stompboxes circuits published in magazines, books or on DIY electronics websites.

Subspace Transmission - A fuzz with a recording and playback

Postby Freppo » 18 Mar 2016, 13:31

Hi folks,

Here's a new DIY project release from me - the Subspace Transmission Fuzz.
It's a fuzz with a recording and playback feature based on the ISD1820 voice recording chip.
It can record up to 20 seconds and the playback can be repeated and pitched up or down.
It's a pedal you can have alot of fun with... :)

It's an easy build that doesn't require any programmable chips.


Link


More info in my blog at http://www.parasitstudio.se

I hope you like it
Cheers, Fredrik
Check out my building blog at http://www.parasitstudio.se

For this message the author Freppo has received thanks: 5
Bill_Mountain (21 Mar 2016, 02:36), induction (18 Mar 2016, 23:18), jrod (18 Mar 2016, 15:12), karul (18 Mar 2016, 14:42), mirosol (19 Mar 2016, 16:07)
User avatar
Freppo
Breadboard Brother
 
Posts: 58
Joined: 14 Sep 2013, 13:37
Has thanked: 16 times
Have thanks: 117 times

Re: Subspace Transmission - A fuzz with a recording and play

Postby mirosol » 19 Mar 2016, 16:21

First, would lowering the values for R3, R4, R15 and R18 help with the output level issue?

Second (as i couldn't find my answer in the datasheet), does the chip suport simultaneous rec/play with different samplerates? You probably guess where i'm going with this :)
User avatar
mirosol
Resistor Ronker
 
Posts: 261
Joined: 11 Mar 2012, 17:15
Location: TKU, FI
Has thanked: 153 times
Have thanks: 358 times

Re: Subspace Transmission - A fuzz with a recording and play

Postby Freppo » 19 Mar 2016, 21:09

mirosol wrote:First, would lowering the values for R3, R4, R15 and R18 help with the output level issue?

Second (as i couldn't find my answer in the datasheet), does the chip suport simultaneous rec/play with different samplerates? You probably guess where i'm going with this :)


Yes, the output could probably be raised by lowering those resistors, but the sweep of the tone would suffer.
I'm working on a revision with a different kind of tonestack (with less volume loss) and a makeup gainstage insted of the buffered Vref (isn't really needed).
It will overall have less components and be able to be quite a bit louder than unity. :)

The chip is a single message chip, so it's not possible to do simulanious playback and recording for overdubs/bouncing.
That would require two chips. I'm actually working on a two chip version already. :)
The tricky part is to have both chips controlled in a logic fashion, perferrable sharing controls.
Setting up the controls for one of these chips was hard enough, as I had to use CMOS flip flops with switch debouncing.

The most annoying drawback of these chips is that they always powers down into a powersaving state before beginning playback again, so fluid repeats is not possible.
There will always be a short (like a half second) delay between the repeats.
Check out my building blog at http://www.parasitstudio.se
User avatar
Freppo
Breadboard Brother
 
Posts: 58
Joined: 14 Sep 2013, 13:37
Has thanked: 16 times
Have thanks: 117 times

Re: Subspace Transmission - A fuzz with a recording and play

Postby mirosol » 19 Mar 2016, 22:49

Thanks for clarifying. True, the resistance before BMP-style tone stack would afftect to control. What comes to raw output level. More is always better. At least in my opinion. I seem to favor quite hot pickups, so the lower than unity level performance for a pedal is basically a show stopper.

The idea of dropping/doubling the sample rate for playback would be the key in gaining a polyphonic octave/pitch shift effect - Something that's been sorely missed as (even remotely) simple diy circuit. So it seems that this chip wouldn't work as one.
User avatar
mirosol
Resistor Ronker
 
Posts: 261
Joined: 11 Mar 2012, 17:15
Location: TKU, FI
Has thanked: 153 times
Have thanks: 358 times


Return to DIY Stompbox designs

Who is online

Users browsing this forum: No registered users and 6 guests