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Issue with a LTC and a Casio SK1

Started by project null, November 11, 2020, 01:00:57 AM

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project null

hey there!

sorry for creating again another thread about the sk1, but I really need your help and I don't find the answer anywhere. sorry also about being the guy that just created an account today and already asks for tips, I hope you won't find it offensive.

I posted a video on reddit some days ago about a issue with a LTC and a SK1 : https://www.reddit.com/r/CircuitBending/comments/jnyrpd/issue_with_ltc1799_oscillator_and_casio_sk1/ where I followed the User 173's tutorial on YouTube, but even if I am 100% sure I followed the diagram he posted, I have a lot of glitches while turning the potentiometer (you can hear it on the video I made on reddit), until it goes an octave lower and it's fine. I thought my chip was defective, so I bought another one today and I have the same problem.
I tried to use various resistors, but I honestly don't really know what I'm doing. mad_marbled on the thread told me this : "Looking at the data sheet, you want to maintain a minimum resistance on the DIV pin.(pin 4) of 5-10Kohms." the DIV pin is the one that goes into the potentiometer, right? I tried many different values between 5 and 10kohms, and at 10kohms I have no more glitching but it drops about an octave lower when I engage the switch, and I don't think it is supposed to sound like this.

I know it sounds unorganized and my english is far from perfect, I really hope you will understand my problem and eventually you could help me.

Thank you very much, and have a nice day!

Circuitbenders

Why have you written that we don't do technical support on that post?

You might just have a very dirty and intermittent pot there. The trimmer pot on the LTC module is enough to keep the SK1 from crashing when its adjusted correctly. You don't need extra resistors.

Theres no real way of helping here without knowing exactly how you've tried to wire it in.
We usually wire an LTC in as on the attached image
i am not paid to listen to this drivel, you are a terminal fool

project null

hey, really sorry about this, but when I read on the contact page "1 - We are not a repair company, and we don't usually do general servicing and repairs unless we're installing mods on a machine at the same time.", I thought I was not legitimate to get in touch with you as I've just bought the LTC chip and not an actual mod on my sk1.

thank you very much for your diagram, what was wrong with the mod was the cut on the pcb, not deep enough, it was probably messing with the pot. whatever, now it works and I am super happy with it, so thank you again!

wax+wire

glad to hear you got it working. always good to check continuity when you cut a trace.

Just wondering, what range of pitch bending do you get? I thought it was possible to bend more than octave up and an octave or two down, but I don't get anywhere near an octave up on mine.  It has been many years since of touched it, and I now have cheap octave pedals in my rig that I use to get bass/super high parts.

project null

thanks for the advice about checking the continuity, I will for sure remember doing it in the future if i have to cut a trace!

hmm I tuned it so the range is exactly one octave up, but iirc I could tune it a bit higher (maybe one octave and a fifth/tritone) - i will confirm that soon. octavers are cool, I will soon buy one of those cheap behringer/chinese/unbranded. did you tried bending them (and if yes did you find interesting sounds)?

wax+wire

I use the Mooer Pure Octave +/- 1 or 2 octaves. Lots of options.  Definitely adds some artefacts. I've also used the hotone octave pedal.

I haven't bent any of them as they are both really small, and I imagine really tiny SMD circuits.