MaxiKORG DV800 CV/Gate mod ?

Any music gear discussions that don't fit into one of the other forums.

Moderators: Joe., lisa, luketeaford, Kent

User avatar
jabberwalky
Common Wiggler
Posts: 142
Joined: Sat Jan 21, 2012 6:44 pm

Post by jabberwalky » Sun Jan 01, 2017 8:23 am

I'm about to dive into the project. How is everyone doing the sequencing? I'd ultimately like to sequence both Upper/Lower independently. I thought the Korg sq1 would be a cheap option, but it is unable to convert midi to hz/v (only works via the usb from what I understand) and it also only converts 1 channel.

I also have a Paia midi/cv that's part of my 9700s. As far as I know it doesn't natively output hz/v though. Anyone have experience doing that?

Thanks and happy new year!
www.karlojanpa.com - film composing
https://www.youtube.com/user/jabberwalky/ - Synth demos and more

User avatar
wiperactive
Wiggling with Experience
Posts: 413
Joined: Sat Apr 12, 2014 12:17 pm
Location: Gloucestershire, UK

Post by wiperactive » Sun Jan 01, 2017 9:32 am

jabberwalky Paia do an easy to build linear-to-exponential converter in the shape of the 9756K module. Maybe two of those will take care of upper/lower section hz/v requirement.

EDIT Correction:

Apologies! I believe that's the wrong direction of conversion in this case, though the 9756K could still be worth knowing about for CV traffic in the other direction.

User avatar
Jruss993
Learning to Wiggle
Posts: 42
Joined: Mon Sep 23, 2013 1:55 am
Location: Canada

Post by Jruss993 » Sat Mar 24, 2018 3:50 pm

Hey!

Do you have any pcbs left?

I'd love to mod the maxikorg once I get it

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Sat Mar 24, 2018 6:18 pm

Pretty sure there are some, will check today

User avatar
Cymatics
Wiggling with Experience
Posts: 368
Joined: Sat Apr 24, 2010 12:57 am
Location: Sydney, AU

Post by Cymatics » Mon Mar 26, 2018 12:21 am

andrewF wrote:Pretty sure there are some, will check today
I’d be interested in one too if you have another spare, thanks!

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Mon Mar 26, 2018 1:28 am

andrewF wrote:Pretty sure there are some, will check today
got heaps :party:

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Wed Apr 18, 2018 4:44 am

I need one for my newly acquired DV800!

I just sold my CS5 to a friend, would this work on that as well?

Will DM you.

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Wed Apr 18, 2018 7:45 am

afaik it only works with the dv800

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Mon Apr 23, 2018 4:02 pm

What are recommendations for component sellers in the US?

Also, what mods have you guys done besides CV/Gate?

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Mon Apr 23, 2018 7:29 pm

In the US best is Mouser but very difficult to navigate if you are new to purchasing components.
Far easier and much cheaper is Tayda

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Tue May 08, 2018 2:48 am

I have all but 3 of the components in my Tayda cart, I can't find

10μF electro (at least 35V rating)
78L15 regulator
100nF capacitor (ceramic ok) (2.5mm spacing)

Are there alternatives I can use from that site?

This is my first circuit building project so I am pretty clueless.
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Tue May 08, 2018 12:55 pm

MrTea_SF wrote:I have all but 3 of the components in my Tayda cart, I can't find

10μF electro (at least 35V rating)
78L15 regulator
100nF capacitor (ceramic ok) (2.5mm spacing)

Are there alternatives I can use from that site?

This is my first circuit building project so I am pretty clueless.
You can use the 7815, its a bit chunky tho. Also be aware its pinout is opposite the 78L15, so install it backwards - Tayda 7815 Prob best to get a 78L15, ebay will have them cheap.

Tayda 10uF cap

Tayda 100nF cap

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Tue May 15, 2018 1:26 pm

Thanks for your help again.

Related question...

When do you know to recap old synths?

I recently got the 800DV, Octave Cat and a rare Soviet RMIF Opus. I don't think any of them have been serviced in a while.
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
elmegil
Super Deluxe Wiggler
Posts: 2947
Joined: Sun Apr 29, 2012 2:57 pm
Location: Chicago

Post by elmegil » Tue May 15, 2018 1:43 pm

MrTea_SF wrote:When do you know to recap old synths?
There's a can of worms.... :-)


Check that the PSU is putting out rated voltages. If not, the PSU alone may be in need of re-capping.

Across the rest of the synth, *MY* watch word is, if it is working to specification, don't mess with it. The main exception being if you see physical changes to caps (usually electros bulging) or leakage, those and ones like them ought to be replaced.

Blindly replacing all the caps in a synth because it's old touches so much of the synth that you're almost as likely to cause a new problem as solve any impending ones.

But there are a lot of more seasoned techs than I am who will disagree. Hence "can of worms".


Edit: IMO more important than how long since servicing is how they were used. If they were in steady use? Probably just fine. If they were mothballed for years, then that's a different matter, there are types of caps that don't like to go without current for extended periods.

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Tue May 15, 2018 1:54 pm

I see. The guy who sold me the Opus said it would need recapping, some of the rotary knobs need replacing etc too.

I read that you can tell sometimes by noises gear makes when the caps are bad.

The 800 sounds fantastic though :love:


FYI this is the OPUS.

Image
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
elmegil
Super Deluxe Wiggler
Posts: 2947
Joined: Sun Apr 29, 2012 2:57 pm
Location: Chicago

Post by elmegil » Tue May 15, 2018 1:58 pm

MrTea_SF wrote:I see. The guy who sold me the Opus said it would need recapping, some of the rotary knobs need replacing etc too.

I read that you can tell sometimes by noises gear makes when the caps are bad.

That Opus is gorgeous.

I have replaced caps that were in the signal path and caused static and noise -- that's *not* performing to spec though.

There's a lot of mythology about recapping or not out there. Like I say, there are experienced techs who would likely agree with the seller, so just take my opinion for what it is -- my opinion :).

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Thu May 17, 2018 7:51 pm

elmegil
Thanks!

Back to topic, what was your final mod for the Korg? You mentioned using various switches. Also did you add the filter mod?

The original parts list was missing a few things like the header and the thing that holds the IC's, what should I get?

Also does anyone have an Octave Cat SRM here?
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
elmegil
Super Deluxe Wiggler
Posts: 2947
Joined: Sun Apr 29, 2012 2:57 pm
Location: Chicago

Post by elmegil » Thu May 17, 2018 8:19 pm

Quite honestly the Korg was so long ago, and for someone else, that I don't recall the entire job.

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Wed May 23, 2018 2:43 am

I am nearly done building the little mod.

Is there anyway to test it before I install it in the Korg?
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Mon May 28, 2018 10:09 pm

Another question, I am looking at the "From Accessory" inputs on the back, I am a little confused as they don't seem to be connected to anything.

Do I need to add my own external inputs?
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Wed May 30, 2018 12:04 am

On mine, I rewired and relabelled the accessory jacks as I did not use them for anything otherwise.

It is up to you.

Re:Testing
if you put a signal into CV in you should see it at CV out, with a bit of gain added.
Putting in a gate, you should see it at Repeat out. EG/vibe/bender is usally held high so willdrop to 0V when the gate coming in is on.

The SH gate is a bit harder as it pulls down to -V. You could use a LED to check. Connect the Anode (long lead) to Ground and the cathode to the output. It should turn on when the incoming gate is on. Use an super or ultra bright LED as it has a 10k resistor limiting the current.

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Wed May 30, 2018 2:28 am

Thanks, I will do the same with the external inputs.

Should I connect the power to the output side of the transformer board is there a better location to do that?
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

User avatar
andrewF
Super Deluxe Wiggler
Posts: 4027
Joined: Wed Apr 15, 2009 7:36 pm
Location: WA
Contact:

Post by andrewF » Wed May 30, 2018 5:17 am

MrTea_SF wrote:Thanks, I will do the same with the external inputs.

Should I connect the power to the output side of the transformer board is there a better location to do that?
Can't remember on mine, but wherever is easy to access will do

User avatar
MrTea_SF
Learning to Wiggle
Posts: 36
Joined: Wed Apr 18, 2018 4:37 am
Location: San Francisco
Contact:

Post by MrTea_SF » Thu May 31, 2018 1:29 am

I read back through this post and trying to figure out the switching, you said you have a switch for everything and elmegil was using 3 switches.

I have 2 x 4DPT switches, can I do it with just those?

1. CV in
2. to switch
3. EG/vib/ben
4. S&H

I was thinking one switch for CV Gate for each voice but elmegil suggested needing another to switch between the gate (master gate?)

Also did you use the foot controller for filter control?
[url]https://soundcloud.com/21stsentry/[url]

-------------

Cubase 9.5
DSI Pro 2
Octave Cat
Korg 800DV
Yamaha RY-30
Make Noise 0Coast
Roland SE-02
Roland TR8S
Roland TR-909
Beatstep 1/Pro
TC Electronics Flashback

Herve
Learning to Wiggle
Posts: 2
Joined: Sat May 23, 2020 5:52 pm

Re: MaxiKORG DV800 CV/Gate mod ?

Post by Herve » Sat May 23, 2020 6:39 pm

Hello
I would like to purchase one of these circuits for my DV800.
Do you still have any?
What is the procedure ?
Thank you

Post Reply

Return to “General Gear”