MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

Help needed to fix Octave Cat CV/Gate
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Help needed to fix Octave Cat CV/Gate
MrTea_SF
I have been looking around but cannot find the DIY solution to fix the gate input from 5V to 7.5V as mentioned in the SOS review.

https://www.soundonsound.com/reviews/octave-cat-kitten-voyetra

The only thing I found was this but I am a newbie and this sounds a bit incomplete (or too easy?!?):

"Should be pretty easy, using an NPN transistor (ie 1N3904) as a switch-- detach the original tip wire from the gate jack, attach it to the transistor emitter, collector connected to the 7.5v (tap from the nearest source, your tech should be able to locate this spot with a DVM), new wire from the gate jack going through a resistor into the base of the transistor. Depending on the resistor used this should also work with voltages even less than 5v."
roglok
you can also use an op amp if you don't trust the transistor:



the comparator reference voltage is set via the ratio of the two resistors connected to the inverting input. the diode is there to block any negative voltages.
MrTea_SF
I don't mind using the transistor if it seems like a good solution.

I plugged the Cat into the Beatstep last night but it seems like only the Gate works and I have read other Cat owners being able to use it fine.

I have the SRM version.
roglok
it's not quite clear what your problem is. i was under the impression that you wanted to boost external gate signals to work with the 7.5V gate input of your synth. i'm not sure what you mean by "only the gate works"...
roglok
i just checked some pics online. if your back panel looks like this:



you need to prepare a special cable. according to the panel instructions for the SYSTEM EXPANSIONS you need a TRS (stereo) jack with the tip connected to your gate signal, the ring to your CV signal and the sleeve to ground. if you used a mono cable that would explain why only the gate works (that would have simply connected the CV input to ground)...
MrTea_SF
I have the Cat SRM, with a "From Master" input.

I am pretty sure the cable I am using should be working...

roglok
you can make a 'definitely sure' out of that by switching the cables and checking if the CV input then works or not.

i still don't understand how this is related to your initial gate boost request...
MrTea_SF
I thought the gate wasn't working because the cables were not working in any configuration.

I just tested the tip to tip and ring to ring etc and it looks like the splitter splits to stereo and not 2 monos, problem solved.

Now I just gotta figure out why VCO 1 is not sounding (but capable of modulating)
roglok
MrTea_SF wrote:
I thought the gate wasn't working because the cables were not working in any configuration.

I just tested the tip to tip and ring to ring etc and it looks like the splitter splits to stereo and not 2 monos, problem solved.


you are welcome.
MrTea_SF
Danke.
Modulart_JP
Octave Cat... we're not worthy
What a wonderful synth !
I was lucky enough to own all the 3 versions and kept only the non-SRM.
Sound wise, it is my favorite.
crc
i bought a broken Cat (early 1853 version) earlier this year. got it all fixed and it sounds fabulous. i also have a problem with external CV&Gate.

If i use my Analog Keys (with a stereo cable), i get this strange retriggering of the ADSR envelope. sounds like it's triggered from noise. the retriggering gets faster when i shorten the decay time. Tried all combinations of settings from the Analog Keys, but so far always the same result.

If i use my Kenton Pro Solo II (with a splitter cable), it works fine, but the ADSR part only opens with every new note played. if i play the same note twice, only the AR envelope retriggers as it should.
Pitchbend or vibrato from Kenton CV triggers the ADSR envelope.

The Cat manual says the following:

"Trigger signal is internally derived from changes in gate and control voltage levels. For proper triggering of slaved CAT synthesizer with other than OCTAVE products, control voltages must have no glide and may be either sampled or unsampled".
MUFF WIGGLER Forum Index -> Music Tech DIY  
Page 1 of 1
Powered by phpBB © phpBB Group