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Guitar FX switcher with MidiBox


flo

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  • 2 weeks later...
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For me, the relais needs to be powered to bypass the FX so that the FX is enabled "in rest". When something happens and the unit is not powered anymore, the FX will be enabled in the FX chain and can stilll be manually switched on/off. I rewired the LED indicator so that the LED will be ON when the relais is not powered and the FX is NOT bypassed (thus is enabled in the FX chain). To me, this indicator makes more sense.

ULN relay driver with LED indicator On when not bypassed.JPG

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  • 3 weeks later...

@FoneBone: Great, welkom!

The project was on hold because of building other stuff, like my new pedalboard and an ADA flanger clone.

I have the CORE & DOUT module-kits and relais etc lying on my desk to be build...

Recently I've downloaded and installed the software to program the CORE but haven't tried it yet. I'll do that when the CORE module is build.

Design-wise the project currently misses:

- Actual tested code ready to be downloaded and used. But the code examples currently on my user page should work. Its actually pretty simple when using a DOUT module. ;)

- Inside and outside layout design of the enclosure with the components.

- Desicion on what types of FX-loopers to use:

-- Chains of loopers or

-- Separate loopers or

-- Combination of the two. For me, this option is the most interesting.

- Actual layout of the relay-FX-loopers board. The info on my user page and the posted picts in this thread should point in right direction.

Well, I guess its time to re-start this project again...   ;)

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@flo

While I'm waiting for my new modules, I've build my first two clone stompboxes: Ross (Keeley) Compressor and Phase90. Next one will be a TS-9 clone.

And I've ordered a new display for durisian's pedalboard project, now with 20x2 signs.

Which relais would you recommend?

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@FoneBone :

> Which relais would you recommend?

See:

http://www.midibox.org/dokuwiki/flo#using_dpdt_relays

I've bought simple DPDT relays, rated for 5V 200 ohm 25mA, that were supposed to be good for audio-switching at a small online electronics shop in the Netherlands. I asked the shop holder who I trust with his answers via email. They were 1 euro a piece. ;D

Takamisawa NA5W-K 7a6-001 JAPAN 942588.

http://www.dickbest.nl/webshop/index.php?act=viewProd&productId=986

Try to find something like it in your local area.

I'd keep away from too much advertised b#llsh#t like "special goldplated audiophile grade relays" as they are usually way too expensive...

@stryd_one: Thanks for moving the thread!

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Next to FX bypass loopers perhaps an "AB loop selector" would be a nice addition.

My current favorite setup for the 7 switch options:

- 2 seperate FX loopers with IN OUT SEND RETURN jacks.

- 4 chained FX loopers with 1xIN 1xOUT 4xSEND 4xRETURN jacks.

- 1 AB loop selector with IN OUT A-SEND A-RETURN B-SEND B-RETURN jacks.

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Hmm on the other hand, I usually have two main FX chains:

- FXs for gain / overdrive / distortion (setup between guitar and amp).

- FXs for modulation / delay / reverb (setup in the FX loop of the amp).

So perhaps the FX looper needs to reflect that:

- 3 chained FX loopers with 1xIN 1xOUT 3xSEND 3xRETURN jacks (for the pre-amp FXs).

- 3 chained FX loopers with 1xIN 1xOUT 3xSEND 3xRETURN jacks (for the FX in the amp FX loop).

- 1 AB loop selector with IN OUT A-SEND A-RETURN B-SEND B-RETURN jacks.

Anyone has some suggestions for a good looper setup?

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The AB switch can be used to:

- Select between two signal sources = A-in / B-in -> Output

OR

- Route a signal to one of two outputs = Input -> A-out / B-out

This can be handy to route the guitar either to the FXs & amp or to a tuner. Also nice is to be able to select between amps.

Actually I just found this:

http://www.voodoolab.com/manuals/gcx_manual.pdf

Page 8 "A/B switching", explains how to do that with a "regular" FX looper.  :)

So a collection of "regular" FX loopers is fine as long as they can also be used as AB switches.

The chapters "Audio Loops" (page 7-9) and "Using Loops as Switches" (page 10-11) are interesting.

I want my FX switcher to support these options so I guess I'll be moddeling it to the VoodooLab GCX concerning the loopers (but not its Midi implementation):

http://www.voodoolab.com/gcx.htm

---------------------

I think that a CORE output port (like J5) can directly control a ULN2803 chip. It does not need much current because it uses darlington transistors and it will ensure that voltage/current spikes do not reach the CORE pins.

Then I do not need the DOUT module. For this the source code needs to be changed.

I have collected some info about this subject so far:

Search terms:

J5 as DOUT

J5IO module on SVN

svn.mios - j5_io

use the pins at MBHP_CORE:J5 port as digital inputs and/or outputs

http://svnmios.midibox.org/listing.php?repname=svn.mios&path=%2Ftrunk%2Fmodules%2Fj5_io%2F&rev=0&sc=0

j5_io.h

cheap dout's

http://www.midibox.org/forum/index.php/topic,10534.msg81088.html#msg81088

you can control J5 outputs the following way from C:

Add

  ADCON1 = 0x07;

  TRISA &= 0xd0;

  TRISE &= 0xf8;

to the Init() hook

Now you can toggle the pins with

PORTAbits.RA0 = ...

PORTAbits.RA1 = ...

PORTAbits.RA2 = ...

PORTAbits.RA3 = ...

PORTAbits.RA5 = ...  // no typo! RA4 is allocated by IIC

PORTEbits.RE0 = ...

PORTEbits.RE1 = ...

PORTEbits.RE2 = ...

Driving PIC pins of port B via MIDI

http://www.ucapps.de/mios_c_pic_pin.html

http://www.midibox.org/dokuwiki/mios_pin_list

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  • 4 weeks later...
  • 1 year later...

There was a question on how to make a FX switcher with MidiBox:

I redirected the TS to this thread.

@RockRaver:

"... when you say I only need one DOUT, you're saying i'll only need 1/4th of the DOUTx4 unit, correct? That would make sense as each 74HC595 can control 8 relays, correct?"

Indeed when controlling 7 relays, you only need 1/4 of a DOUTx4 module.

Actually, the CORE could control the 7 relays directly from one of its output headers so DOUT is not needed then, but this is not directly supported by the MIOS software so I decided to use a DOUT.

See also:

http://www.ucapps.de/mbhp_dout.html

http://www.midibox.org/dokuwiki/flo#midibox

Edited by flo
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