Help me fix my Octave Kitten's keyboard switches

glemlyn · Joined: Jun 13, 2011 Posts: 7 Location: france

Thanks for that Jabberwalky, I actually cured my own Kitten by simply leaving it on (i.e. powered up) for 36 hours - eventually it just came good, and since then it still takes a few hours to warm it up before the keyboard control comes back but it's all part of the exciting unpredictable world of analogue synthesis!

Please post the results of your more serious attempt to get it back working...

By the by, it does occur to me that given your CV is still okay (min too for that matter) the Kitten could still be controlled via a MIDI-CV interface (Kenton Electronics do a comprehensive unit for about £150)... so you could still manipulate filters, LFO's etc but play an attached MIDI control keyboard for the actual performance...

Best

g

synchroma

Perhaps we can trace this circuit. I've tried to get in touch with Carmine Bonanino before, with no success. It seems he would never be associated with this earlier existence now as the head of Voyetra (as would Chris Huggett not be associated with the Wasp or OSCar) and I've never known a more flexible monosynth that the kitten...I hope we can work out what makes it so good.
I also have a few switching problems with my kitten, so I will be opening it up with my oscilloscope really soon.
Ed (Synchroma)

Jabberwalky · Joined: Feb 02, 2008 Posts: 9 Location: Pittsburgh, PA

That's really unfortunate that Carmine would like to keep it dead seemingly. Well, as an update to my kitten. The keyboard is now fully functioning. I pretty much did a full sweep of various op amps and one of them got it going. Now the only thing left to solve is the non-functioning LFO. Quite a shame to have one of the strongest points on this synth not working.

Korgy · Joined: Jul 20, 2012 Posts: 5 Location: UK

Hi Just joined. Hopefully with a solution as well as a problem Very Happy

The LFO on my kitten was repaired by replacing the LM307N
There are two on the big board, it is the one that sits in the group of four chips between the sliders It now warbles and responds perfectly to the controls

My VCO is still totally dead but I have ordered a CD4013 which I am guessing as a dual flip flop is the oscillator Confused

I will update. I bought mine "dismantled" and used the video on the web to confirm the chip locations but cannot make out the chip order on the centre row
End to centre I have TL082CP TL082CP mystery1 Mystery2 CA3046 CA3140E and CD4093 in the middle.
If anyone has the board out?

Korgy · Joined: Jul 20, 2012 Posts: 5 Location: UK

VCO update, It was not the CD4013 Sad

Considering swapping the positions of the 2 mystery position chips ( a 3140E and a 307N , a dangerous game though Confused

glemlyn · Joined: Jun 13, 2011 Posts: 7 Location: france

Korgy · Joined: Jul 20, 2012 Posts: 5 Location: UK

Hi Glemlyn
Wow thanks. My problem was that I bought the Kitten (first series) with the chips removed and in a bag (all there apparently) so I had no clue where they went.
I pieced together most locations from photos on the web but that was an incomplete answer. It now all works except the VCO.
What I need is the chip numbers and positions for the main board so need high enough resolution pics to read the chip numbers
Hoping yours has the same board Here is a pic. If not hey ho I will keep waiting and asking around

http://i229.photobucket.com/albums/ee247/skyliner_photos/CircuitKitten001_zpsaf703b60.jpg

Cheers
Korgy[/img]

glemlyn · Joined: Jun 13, 2011 Posts: 7 Location: france

Hi Korgy -

Well, I hope these help, but I should say straight away that Octave clearly had a radical redesign between Kitten I and II! For one thing I have TWO boards, not one!

Anyway, all the chips are on these pix; there's a smallish pic of both boards to give you some geography; a big enough pic of board one to zoom in and read the chips and then some macros for the second board... if you cannot read any of it just holler and I'll spell them out for you.

Hope to catch up with you regarding my Kitten's CV failure at some point,

Good luck with the VCO,

glemlyn
http://s1172.photobucket.com/albums/r575/glemlyn/

Korgy · Joined: Jul 20, 2012 Posts: 5 Location: UK

Hi Glemlyn
Yep It is a completely different circuit. Less chips and a cleaner design/ layout.
Thanks for your efforts though, It still adds to the communal database and will be helpful to someone else I am sure
All the best
Korgy

glemlyn · Joined: Jun 13, 2011 Posts: 7 Location: france

Korgy - yes, does look a *little* different! As you say perhaps someone'll read this at some point and post Series I pix...

Meanwhile, I am very interested in how you got your Kitten to meow after it arriving in a bag of bits... The issue with mine is no CV signal from the keyboard - though the multicore plug is all fine and there is a GATE making it over the bridge... Did you have any similar issues when fixing up yours and do you have any thoughts as to possible things I should look at?

Over the last two years I have found a number of Kitten owners with similar issues on various forums but never seen anyone resolve them - any ideas would be very welcome!

Cheers,

glemlyn

Jabberwalky · Joined: Feb 02, 2008 Posts: 9 Location: Pittsburgh, PA

How many of these are out there? Surely very few! Anyway, I will have to try replacing that LM307 chip you're mentioning Korgy. I'm thinking I did that, but it's been a while and I don't remember. My dead keyboard issue was fixed by my friend Shawn simply by replacing nearly every op amp on the board. Sorry I can't help you pinpoint it. It was doing the same thing however.

Edit: Where did you find your LM307? Seems discontinued, and can't find information on a replacement.

Korgy · Joined: Jul 20, 2012 Posts: 5 Location: UK

Hi Jabberwalky
The LM307 (usually LM307N) crop up frequently on ebay for a 2 to 5 bucks (there are a few on today, I just checked Smile

I have left my mark one for the time being as it need a couple of relatively expensive chips, particularly the unobtainium CE4001AE and CA1458G
But I will get around to it My main ride is the venerable Korg DSS-1. The Octave is a project out of a skip at the recycling center! It played till the VCO stopped but was always difficult to keep in tune as I recall
How many are left is anyones guess there were quite a few, mostly kats, around here in the UK then suddenly they got hard to find and expensive, a bit like Corvairs!
K.

ryandais · Joined: Feb 20, 2013 Posts: 2 Location: new york city

Hi everyone!!

Just signed up for this board, so I apologize for any n00b-ness. Tons of great info on this thread so far, very helpful!

I recently picked up a beat up (but functioning) Octave Kitten. The "A" key is broken in half, but thankfully was able to score a replacement key from Syntaur.

I am going to start taking it apart this weekend to do a massive clean up and teach myself how to replace the broken key. If anyone has done this before, any tips would kindly be appreciated.

My major question is this:

I was able to find schematics online, although they are hand drawn!! and barely legible. My plan is to make proper schematics for it with powerpoint and put them up for free online, just so that its up for people to have. Totally ridiculous that these don't exist online.

Now, two of the switches on it broke off, it is the ADSR Repeat and Sample + Hold Switch on the upper left in the Transient Generator section of the synth. Does anyone know what kind (make / model) switches these are? That part of the handwritten schematics are unreadable. I figure if its just a switch, I can get a replacement one elsewhere online, just need to know what I'm looking for.

If anyone wants me to upload the hand written schematics or post pictures, by all means let me know!

Thanks in advance for any help.
ryan

pdman1 · Posted: Wed Feb 20, 2013 3:50 pm Post subject:

the Calibration manual is here:

http://manuals.fdiskc.com/flat/Octave%20Kitten%20Calibration%20Procedure.pdf

Can you post your hand drawn schematics?

ryandais · Joined: Feb 20, 2013 Posts: 2 Location: new york city

Yeah, found the calibration manual easily (although I'm not calibrating just yet)...need to mainly figure out the replacement switch situation.

I will post the hand drawn schematics tomorrow for sure!

pdman1 · Posted: Wed Feb 20, 2013 3:57 pm Post subject:

sorry for the same multiple posts. I was getting an error message and didn't realize the post went through.

blue hell · Posted: Wed Feb 20, 2013 5:29 pm Post subject:

Jabberwalky · Joined: Feb 02, 2008 Posts: 9 Location: Pittsburgh, PA

Hi all, here's the schematic that I painstakingly tried to merge into one large image. Some of the text had to be retyped for being illegible, and it could certainly use more (if I had the time) I think I finally found it at synthparts.com but it was in multiple pieces. I work at a blueprint shop so I just printed a huge 3'x4' version of it.

http://www.fileden.com/files/2011/2/16/3081548/karl%20kitten%20schematics%20new_compressed.pdf

synchroma · Posted: Sat Sep 21, 2013 1:16 pm Post subject:

Jabberwalky, can you try to post the schematics to a site we don't have to pay for? I don't want to subscribe to fileden!

Alternatively you could email me and I'll host them on my website. morph_2016@yahoo.co.uk

I have been inside my kitten recently to fix a switch, LFO delay and the keyboard, and have taken lots of pictures. I have to put it together now because my friend just bought one, and we want to test the duophonic capabilities of TWO kittens (my mouth is watering as I write this Twisted Evil

). So, if we could put our heads together - is yours a Mk1 or Mk2?

Mine's a Mk2. I'll try to put pictures together into a more reasonable board-by-board form soon. http://sharktracks.co.uk/Octave_Kitten_II.zip

Here's Carmine Bonnano in Forbes magazine (no wonder he's hard to get in touch with): http://www.forbes.com/sites/stevecooper/2012/06/21/qa-scoring-insights-from-three-gaming-businesses/

Best,
Ed

synchroma · Posted: Sat Sep 21, 2013 3:30 pm Post subject:

Hey guys,

Look, Kitten schematics are hard (or impossible) to find. I'd really like to get in touch with the designer, and I've found a lead. But, it seems I don't have Outlook installed and I never use it. However, it seems there's a way of getting his email address from http://www.zoominfo.com/p/Carmine-Bonanno/968286

Can anyone else try this, and plead with the guy to give us schematics for the Kitten?

By the way, schematics for the Cat SRM can be downloaded at http://clacktronics.co.uk/synthesizer/octave-cat-srm-repair

BUT the Kitten uses a Curtis CEM3340 chip and I don't think the Cat does, so it's only somewhat useful.

Sauraen · Joined: Feb 20, 2014 Posts: 1 Location: US

Hey everyone.

A friend just gave me a partly-working Kitten (old version with two boards and two keyboard contacts), and in order to repair it I looked online for schematics. But it doesn't seem there are any available (at least not for free), so I decided to transcribe the schematics from the boards. I have done this with another device (Rockson CP-40 chorus pedal) and successfully modified it based on my schematics, so even though this is a bit more complicated, I'm giving it a try.

The schematics (and some hi-res board photos) are up on my website here: http://www.prongsoftware.com/synths/kitten/index.html

As of 2/20/2014, I finished transcribing the filter board (board B).

Edit: @Korgy CE4001AE and CA1458G may be unobtainium as those part numbers, but as CD4001 and LM1458 both are readily available (e.g. from Mouser for $0.54 and $0.97 respectively). Smile

My Kitten actually has a CD4001 instead of CE4001. Cross-check the datasheets before you order them, but they seemed right to me.

Jabberwalky · Joined: Feb 02, 2008 Posts: 9 Location: Pittsburgh, PA

Thanks Saureen! I've actually been working on cleaning up a really shitty scan of the schematics as well. I'm mostly working on boardA trying to solve a dead LFO issue.

delayed · Joined: Jun 24, 2008 Posts: 130 Location: TN

Did anyone have a copy of the Kitten schematic? I have the same dead VCO issue.

Hotparadox · Joined: Jan 18, 2024 Posts: 1 Location: London

Hello. I am having similar issues with the keyboard not sending CV to the VCO but getting correct voltages at the CV output jack. I have the Kitten II schematics.