Pitch Mod for SP303 // SP404 // SP404SX // ZOOM Sampletrak


#1
a lil budding tradition of mine for the last couple NAMMs.
try to do something new with what you already have.

this time, i tried modding some samplers that i already own/cherish.

the SX had some particularly scary moments. i killed the audio twice while trying to solder to the microscopic points.

https://www.instagram.com/p/BfEj0gYn_dd/
https://youtu.be/-J0jJPYTcPc


#2

Want, that’s awesome!!


#3

Dude, that is some cool ass shizz


#4

<span style=“font-family: “Arial Black”; font-size: -webkit-xxx-large;”>Taech mae


#5

I need schooling



#6

dope!


#7

thanks yo! just in case its not clear. this is not just for pitching sample playback.


it works for sampling. and also extends sample time way beyond stock.
not that it matters a ton for like the SX which has a ton of storage,
but for something like the 303, zoom or even the internal banks on the OG.
either way u can record at all sorts of sampling rates previously not possible.
even change it while u are recording.

also affects (effects?) all the FX. so longer delay times/reverbs are possible. slower wow&flutter and noise on vinyl sim.
slower rates on all modulated effects (anything w/ a rate knob basically). chorus, phaser, wah, etc etc
different responses / tonal qualities of all the other effects.

doesn’t pitch your audio input (ext source) but it does change the sample rate. so more lofi sounding.

the button is for disconnecting the mod, allowing stock operation. so far no crashing when switching back and forth live.

i also tried this on my SP202 and MPC500 and a microgranny w/o any luck :frowning:

#8

Can you explain a bit more about what the mod does?
(Never used one of these :slight_smile:


#9
Can you explain a bit more about what the mod does? (Never used one of these :)

knob controls the clock speed of the DSP chip.

the DSP chip is in charge of audio stuff, fx, sampling etc.
slowing down the clock speed allows the DSP chip to run slower than normal
while not affecting operations of the rest of the device.

#10

Wow, that’s clever :slight_smile: Thanks for explaining.


#11

generally speaking the mod itself is not anything new.


i never saw anyone try this on the samplers that i tried it on tho.
or atleast document it. doesn’t mean nobody else has figured this out.

i had a lot of fun learning.
couple heart stopping moments
these are some of my favorite devices of all time
so i was extra careful/worried about breaking something i couldn’t fix.

#12

Please tell me you took pictures and documented the process??!


If you could post a how to guide I would be very grateful, would love to do this to my SX

#13

honestly, i wouldn’t recommend doing this on the SX

unless u have a good amount of experience modding with super tiny SMD parts
and the proper tools. both of which, i do not possess.

obv it works fine, but the others were much easier and way less risky.
if something happens these parts are almost impossible to replace by hand.

it is possible to break your SX (which i sorta did btw)
which is not fun at all.

#14
honestly, i wouldn't recommend doing this on the SX
unless u have a good amount of experience modding with super tiny SMD parts
and the proper tools. both of which, i do not possess.

obv it works fine, but the others were much easier and way less risky.
if something happens these parts are almost impossible to replace by hand.

it is possible to break your SX (which i sorta did btw)
which is not fun at all.

How much easier is it on the 303 & 404 OG?


#15

Whooooooaaaa dude this sick. How easy is the mod? Is it just a pot acting as a pull-down on the right DSP pin?


#16

not quite. using an external clock that is variable w/ a pot.

look up ltc1799
several quality guides already out there on how to use them.

service manuals are sometimes helpful for identifying what chips are what, where everything is.
u can do it blindly tho as i couldn’t find one for every device.

desperately seeking SP404SX service notes and SP555 as well if anyone has the hookup.

#17
Welp.. doesn't sound like I'll be doing this mod then.. bit over my electronics skill level.
But you did inspire me to open it up and have a look, and I ended up adding an evil mickey under the screen haha

Capture

#18

do you remember the Pinouts you used for the DSP chip? Got the LTC1799 and looking for the schematic somewhere


#19

pinouts on the 404 you used to connect the LTC1799 to*


#20

Found the schematic, are you using the XTI / XTO pins on the IC10 (DSP) or did you have to mod IC11 (Custom Chip) where the Crystal Oscillator input goes to?