Korg Monotron Schematic

rico loverde · Post by **rico loverde** » Fri Nov 05, 2010 11:36 am

thought some of you might enjoy / appreciate this...gotta get one so I can take it apart!!!!!

Luka · Post by **Luka** » Fri Nov 05, 2010 11:55 am

i like it how korg are publishing the schematics and somewhat endorsing the modding of this machine.

Tim Stinchcombe · Post by **Tim Stinchcombe** » Fri Nov 05, 2010 3:07 pm

Lots of Brownie points to Korg for releasing it! Here is the link to the original pdf:

http://www.korg-datastorage.jp/Manual/monotron_sch.pdf

tIB · Post by **tIB** » Fri Nov 05, 2010 3:09 pm

Just me · Post by **Just me** » Fri Nov 05, 2010 4:20 pm

I'll not mod mine. Too fun as it is. Now, if I get a second one, I have plans for it!

audibleobsession · Post by **audibleobsession** » Sat Nov 06, 2010 12:19 am

This is amazing! Thank you so much for posting this, exactly what I was looking for

EATyourGUITAR · Post by **EATyourGUITAR** » Sun Nov 07, 2010 11:41 pm

they know that they just sold +1000 more monotrons by posting the schematic. its probably all SMT. you could never ever build it cheaper unless you are korg. clever marketing. like the fake light up vacum tubes they're pushing in fake hammond b3's

rico loverde · Post by **rico loverde** » Sun Nov 07, 2010 11:47 pm

my buddy is cloning it on a breadboard right now, will post the results if it worx

audibleobsession · Post by **audibleobsession** » Mon Nov 08, 2010 11:25 am

rico loverde wrote:my buddy is cloning it on a breadboard right now, will post the results if it worx

Wow! Right on! Please keep us posted with a new thread on this one! Also curious about the overall quality that you'd get out of it vs. the SMT.

EATyourGUITAR · Post by **EATyourGUITAR** » Mon Nov 08, 2010 12:19 pm

I would like to see the filter section by itself as a DIY. I heard it is some super rare lawsuit filter that no one is allowed to make (korg owns it) and korg brought it back from the dead with the monotron. if I remember, i think korg now owns patents on the filter chips that moog was using back in the day. they stopped making the chips after they bought the patent. assholes.

rico loverde · Post by **rico loverde** » Mon Nov 08, 2010 12:27 pm

EATyourGUITAR wrote:I would like to see the filter section by itself as a DIY. I heard it is some super rare lawsuit filter that no one is allowed to make (korg owns it) and korg brought it back from the dead with the monotron. if I remember, i think korg now owns patents on the filter chips that moog was using back in the day. they stopped making the chips after they bought the patent. assholes.

thats actually what he is focusing on, the filter section. the idea is to have a very small korg filter for use in his circuit bending projects

personally I hate Korg, they are really shitty in a lot of their practices. customer service is a joke. the patent thing on the chips just makes me hate them more

Low-Gain · Post by **Low-Gain** » Mon Nov 08, 2010 1:36 pm

heh...

they released the thing with hackers/modders in mind as their primary market. not to mention soccer moms who shop for their kids at guitar center.

i dont recommend using their designs though in any items your friend plans to bend and sell... they released this info probably to protect it in a legal form. So if you get caught cloning say the filter section and putting it into a box that you sell... bam.. you could get a pretty good spanking.

either way for the DIY'ers and gear hackers this will be great fun.
I still need to buy a couple of these.

Tim Stinchcombe · Post by **Tim Stinchcombe** » Mon Nov 08, 2010 2:10 pm

EATyourGUITAR wrote:I heard it is some super rare lawsuit filter that no one is allowed to make (korg owns it) and korg brought it back from the dead with the monotron. if I remember, i think korg now owns patents on the filter chips that moog was using back in the day. they stopped making the chips after they bought the patent. assholes.

There are no patents surrounding the filter that I know of: the Korg35 'chip' that formed the core of the filter in original MS-10s and earlier MS-20s was a handful of SMT transistors on a small PCB 'substrate' - Korg divulged the arrangement about 10 years ago, but doubtless others had reverse-engineered it before then (though perhaps keeping it to themselves, in times pre-dating the internet...).

I'm also pretty sure Moog wouldn't have been involved in this particular circuit (assuming I'm reading what you say correctly, i.e. that this part follows from the first). Korg stopped using the Korg35 of their own volition as far as I am aware, ditching the design as now used in the Monotron, for one based on LM13600 transconductance amplifiers for later MS-20 models (i.e. it seems there was something about it they weren't happy with...).

Lots more stuff on this on my page of links and things:

http://www.timstinchcombe.co.uk/synth/korg.html

(I don't claim to be an expert on old Korgs - or any old synths for that matter - so I'm happy to hear of any errors or inconsistencies therein...)

Tim

rico loverde · Post by **rico loverde** » Mon Nov 08, 2010 2:37 pm

Low-Gain wrote:heh...

they released the thing with hackers/modders in mind as their primary market. not to mention soccer moms who shop for their kids at guitar center.

i dont recommend using their designs though in any items your friend plans to bend and sell... they released this info probably to protect it in a legal form. So if you get caught cloning say the filter section and putting it into a box that you sell... bam.. you could get a pretty good spanking.

either way for the DIY'ers and gear hackers this will be great fun.
I still need to buy a couple of these.

is it that dangerous on one offs? Ive always wondered about that. I remember in graphic design if you changed a design by 30 percent (roughly) it could then be used as yr own. not sure if the same applies to electronic patents. ill def pass this on to him though..

Low-Gain · Post by **Low-Gain** » Mon Nov 08, 2010 2:52 pm

as a one off probably not, but if you use it in every one off.. it's not really a one off now is it?

I'm just saying if you cloned it 100% and simply tossed it on the output of say a circuitbent piece of gear or a silly 555 oscillator or something it's still something you could get nailed on. it's a risk.

but there's a reason why korg is releasing this info. and i'd think twice about going and just jacking their circuit to use in your own one off pieces that you plan to sell.

that's just my opinion ya know?

audibleobsession · Post by **audibleobsession** » Mon Nov 08, 2010 9:04 pm

How does this apply to guys that mod stuff and then sell it? I'm thinking of someone like Robert Keeley in particular who's made quite a name for himself out of moding guitar pedals.

EATyourGUITAR · Post by **EATyourGUITAR** » Sun Nov 14, 2010 8:56 am

the story I got was that there was an a filter IC in some old moog. probably a voyager or memory moog. I dont know. I dont even know if the story is accurate. that same person said that the monotron filter section IS the circuit from the discontinued IC. so that IC is rare as shit. you would have to butcher an old moog. at least if they wont build the IC we can just use a monotron as a giant IC.

Repeater · Post by **Repeater** » Sun Nov 14, 2010 2:56 pm

so fucking awesome. i can't wait to hack mine.

so is the trim pot accessible from the outside near the volume pot 'bias'?

Tim Stinchcombe · Post by **Tim Stinchcombe** » Sun Nov 14, 2010 5:20 pm

Repeater wrote:so is the trim pot accessible from the outside near the volume pot 'bias'?

That is the 'range' trimpot, which affects the range of the ribbon keyboard - it is 'VR1' on the schematic, in the VCO section.

Tim

Repeater · Post by **Repeater** » Sun Nov 14, 2010 11:29 pm

Tim Stinchcombe wrote:
Repeater wrote:so is the trim pot accessible from the outside near the volume pot 'bias'?
That is the 'range' trimpot, which affects the range of the ribbon keyboard - it is 'VR1' on the schematic, in the VCO section.

Tim

ah great. didn't notice that on the schematic. thank you!

MOD WIGGLER

MOD WIGGLER

Korg Monotron Schematic

Korg Monotron Schematic