Author Topic: Digital echo on embedded processor.  (Read 8340 times)

Stu

Digital echo on embedded processor.
« on: March 29, 2010, 05:32:31 AM »
I found this project on hackaday.

http://dev.frozeneskimo.com/embedded_projects/audio_echo_effect

It looks overkill for an just an echo, but I think that the concept is right. I also like the LTspice sim work, I haven't been bothered with that before, bat maybe I should.

The Chip has A/D and D/A on board and with some opamps, I think this would give anyone wanting to do a digital effect (not just an echo) a good starting platform.

http://hackaday.com/2009/11/21/review-mbed-nxp-lpc1768-microcontroller/

Is anyone using these (or anything similar)?

 

cctsim

Re: Digital echo on embedded processor.
« Reply #1 on: March 30, 2010, 07:43:30 PM »
12-bit ADC and 10-bit DAC doesn't sound very professional by current standards.

Taylor

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Re: Digital echo on embedded processor.
« Reply #2 on: March 30, 2010, 09:32:43 PM »
I know I keep beating the same drum (is that an idiom?) but the FV-1 is the goto hardware for something like this. 24 bit a/d/a and up to 48k sampling rate. Programming a delay is easy as heck. If anyone wants to build one, I'll write the code and release it here for free (gratis+libre) use.

Hardware-wise, you can just build the Tonepad FV-1 reverb PCB and load the new program in.

cloudscapes

Re: Digital echo on embedded processor.
« Reply #3 on: March 31, 2010, 06:24:48 PM »
I'm guessing one thing that scares a lot of people regarding the FV-1 is the package. I'm thinking it would be a bit more  opular if it was sold on "stamps"
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Taylor

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Re: Digital echo on embedded processor.
« Reply #4 on: March 31, 2010, 06:28:13 PM »
Yeah, you could be right. Though I don't find the package nearly as hard to solder as I thought it would be. I hand solder it and haven't ever had one die or not fire up properly.

Taylor

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Re: Digital echo on embedded processor.
« Reply #5 on: April 03, 2010, 01:57:35 PM »
You know, I just remembered that they do make something like a stamp.

http://oct-distribution.com/

peterv999

Re: Digital echo on embedded processor.
« Reply #6 on: April 05, 2010, 10:41:05 AM »
You know, I just remembered that they do make something like a stamp.

http://oct-distribution.com/

I'm sure there are motherboards that would take this  FV-1 gem based  daughterboard already ;)
« Last Edit: April 05, 2010, 10:43:29 AM by peterv999 »

Hides-His-Eyes

Re: Digital echo on embedded processor.
« Reply #7 on: April 05, 2010, 10:56:18 AM »
You know, I just remembered that they do make something like a stamp.

http://oct-distribution.com/

$28 plus a case and controls sounds like quite a good deal for something like this.

armstrom

Re: Digital echo on embedded processor.
« Reply #8 on: April 05, 2010, 12:53:18 PM »
The only problem I see is that you will need to desolder the external eeprom chip and reprogram it yourself. The advantage of the tonepad board is that you can use either SOIC or DIP memory for the external programs. If you use DIP you can easily use a socket and reprogram the memory as often as you like.  Also keep in mind that this board probably isn't buffered for guitar use so you would still have to add additional circuitry that is already built-in to the tonepad layout. But you are correct, you wouldn't need to solder any SMT stuff.
-Matt

Taylor

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Re: Digital echo on embedded processor.
« Reply #9 on: April 05, 2010, 12:58:58 PM »
Yeah, the point of a stamp is to be interfaced into a larger board with buffers, etc. It isn't meant to be an inclusive solution. I designed my own PCB because none of these boards were idea for me.

octfrank

Re: Digital echo on embedded processor.
« Reply #10 on: April 05, 2010, 01:07:27 PM »
The only problem I see is that you will need to desolder the external eeprom chip and reprogram it yourself.

Actually the 2-pin header on top connects to the data and clock pins of the EEPROM so you can do in-circuit programming, no de-soldering/soldering required.

Also keep in mind that this board probably isn't buffered for guitar use so you would still have to add additional circuitry that is already built-in to the tonepad layout. But you are correct, you wouldn't need to solder any SMT stuff.

True, that was with intent as many people like to put their own buffer in place depending on use (i.e. stomp box, in an amp, in a mixer, etc.), their preferred opamp, etc.

-Frank
OCT Distribution
Frank Thomson
Experimental Noize

Stu

Re: Digital echo on embedded processor.
« Reply #11 on: April 05, 2010, 02:47:58 PM »
Cheers for that link.

I have already tried a FV-1 but the SMD soldering lead to me frying the chip. I'm looking to avoid SMD in further projects.

I think I'll get one of these any hook it up to the rest of my otherwise useless FV-1 board.

/Stu



Hides-His-Eyes

Re: Digital echo on embedded processor.
« Reply #12 on: April 05, 2010, 02:58:10 PM »
The only problem I see is that you will need to desolder the external eeprom chip and reprogram it yourself.

Actually the 2-pin header on top connects to the data and clock pins of the EEPROM so you can do in-circuit programming, no de-soldering/soldering required.

Also keep in mind that this board probably isn't buffered for guitar use so you would still have to add additional circuitry that is already built-in to the tonepad layout. But you are correct, you wouldn't need to solder any SMT stuff.

True, that was with intent as many people like to put their own buffer in place depending on use (i.e. stomp box, in an amp, in a mixer, etc.), their preferred opamp, etc.

-Frank
OCT Distribution


haha, we were talking about you, not to you :)

Needs buffering to line level and bringing back down, or just any old 1-transistor unity gain buffer?

octfrank

Re: Digital echo on embedded processor.
« Reply #13 on: April 05, 2010, 03:16:27 PM »
haha, we were talking about you, not to you :)

I'm used to being talked about (at least you do it nicely)  :icon_cool: I appreciate that Aron lets manufacturers announce items of interest here and answer user's questions here. I try to not abuse that privilege.

Needs buffering to line level and bringing back down, or just any old 1-transistor unity gain buffer?

What ever works for your application, just make sure the signal doesn't exceed 3Vp-p for a clean signal (actually depends on program), 3.3Vp-p if you want the chip to clip it.
Frank Thomson
Experimental Noize

Taylor

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Re: Digital echo on embedded processor.
« Reply #14 on: April 05, 2010, 03:47:46 PM »
I'm using opamp buffers with no gain, and they work well. For low-level pickups like strats, a little gain is good.