Author Topic: Random questions before purchase  (Read 750 times)

6495202

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Random questions before purchase
« on: March 10, 2021, 09:45:48 PM »
Hi,

I'm trying to understand a few random details before planning the built.

- Can I use SPST toggle switches in place of the 3 footswitch buttons at the bottom?
- Do you sell a complete kit with only a bare case, meaning all drilled just not painted/printed?
- Are there any extensions / hacks that could be done at built time to address the 3 concerns at https://treefallsound.com/wiki/doku.php#warnings_about_powering_pi-stomp - maybe a fuse for #3, some diodes for #2?
- Is line level input supported?
- How are DIN and USB MIDI related? Can they be freely routed in software?

Thank you for this project! And thank you in advance for taking the time to answer my questions.

Randall (Admin)

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Re: Random questions before purchase
« Reply #1 on: March 11, 2021, 01:11:29 AM »
Good questions.  Here are my answers:


- Can I use SPST toggle switches in place of the 3 footswitch buttons at the bottom?
Any switch could be used in place of a footswitch, but a “latching” switch like a toggle probably wouldn’t work the way you intend without a slight modification to the pi-Stomp software (https://github.com/TreeFallSound/pi-stomp/blob/master/pistomp/footswitch.py). It expects a momentary signal to change bypass status. Each time the GPIO input is pulled low, the bypass status is toggled. Step on it, the effect is bypassed, step on it again, it’s enabled. A latching switch like a toggle (without a software change) would toggle each time you turned it “off”.  The software change would be almost trivial though.

- Do you sell a complete kit with only a bare case, meaning all drilled just not painted/printed?
Not officially.  I do however have one which was my first CNC prototype.  I'd be willing to give you that for half price ($16 instead of $32).  email: sales@treefallsound.com

- Are there any extensions / hacks that could be done at built time to address the 3 concerns at https://treefallsound.com/wiki/doku.php#warnings_about_powering_pi-stomp - maybe a fuse for #3, some diodes for #2?
The design does include a resettable poly fuse, but the reaction time could be a half second or more.  Damage to sensitive components can occur within milliseconds, so the fuse is mainly there to prevent fire.  Additional diodes (even low dropout) still drop the voltage.  Since the pi wants 5v, and every power supply I tried actually measured slightly less than 5v, I couldn't warrant the extra drop.  Bottom line, use the wrong supply, it might fry.  But given the fuses in the pi and pi-Stomp, it likely won't catch on fire.  To greatly lessen the likelyhood of using the wrong supply, the power connector chosen is a less standard barrel connector with a 2.5mm center pin instead of the more common 2.1mm pin.  This prevents the otherwise likely scenario of using the standard 9v supplies ubiquitous for guitar pedals.   

- Is line level input supported?
By “line level” you probably mean -10dBV (aka “Consumer line level”), roughly 1v pk-pk.  The input buffer has about 2.4 volts of headroom, so yes, it can handle consumer line level or 0dBu Pro Ref Level, but not +4dBu Pro Line Level.  For that you’d at least need to attenuate it before feeding it to the pi-Stomp.  For fine adjustment, you can control the input gain of the digital mixer via the System menu, but if the analog input is too hot, it's already clipped by the time it's hit the digital mixer.

- How are DIN and USB MIDI related? Can they be freely routed in software?
The MOD host allows MIDI learn for mapping controls (pi-stomp footswtiches, "Tweak" knob, expression pedal, and any DIN MIDI or USB MIDI CC messages to plugin settings.  MOD leverages ALSA and Jack for MIDI and Audio.  So, yes, anything you can do with those is possible.  The pi-Stomp and MOD software do not "own" the MIDI ports, they can be routed/shared by whatever software is configured to do so. 


6495202

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Re: Random questions before purchase
« Reply #2 on: March 11, 2021, 05:22:51 PM »
Thank you! I was informed a v2 is in the works, I'll wait for that one.