Synth-DIY Yahoo! Groups Archives

Technical info on Poly800 & analog mods

2015-02-06 by chillipower.uk@...

Hey group,

Been interested in modifying particularly the analog side of a few old analog synths I have.

Particularly with some CV in/out so they can modulate each other, with LFO or oscillator signals.

Doesn't need to be real CV conforming to a standard, I'm not playing pitched notes with it. More gentle modulations or FM modulations, of pitch, cutoff and amp etc. If I can find the routing into the analog side I'll add some jacks onto the back of the synth.

I wondered if:

Anyone has a circuit diagram for the Poly800 and/or has tried this.

Knows about the Korg LFOs, are they software or hardware generated on the Poly800?

Also might have details of a line-in mod. I think I could run the line-in as an alternate (or mixed with) the noise source, so that it runs through the filter and MIDI notes/CC can be used to alter the line signal in interesting ways.

Any thoughts or discussion about these ideas, perhaps some of you have tried out these things already. If so I'm really interested to hear about it.

All the best, Louis

Re: [korgpolyex] Technical info on Poly800 & analog mods

2015-02-06 by Michael Hawkins

Check out the files section and you will find the schematics for the Poly.

The LFO's are all software. But the control signals could be intercepted and set up to be controlled by CV with some op-amps to match the 01V to the required voltage swing range.

VCF cut off is easy. Just intercept the cut off control signal and set up some op amps to converts the 0-1V range to whatever is required. Check the power supply rails to see what the range needs to be.

Amplitude - there are two master control signals for DCO bank 1 and DCO bank 2. They could be intercepted and the same CV with op-amps.

I don't think anyone on this list has done this sort of CV type mod (most use POTS to intercept and get manual control). So you are sailing into uncharted waters but it's relatively straightforward if you know your analog electronics.

Modding to send audio through the filter is very common. Though we don't have any specific mod details in our files section.

/Mike

From: "chillipower.uk@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Friday, February 6, 2015 6:59 AM
Subject: [korgpolyex] Technical info on Poly800 & analog mods

Hey group,

Been interested in modifying particularly the analog side of a few old analog synths I have.

Particularly with some CV in/out so they can modulate each other, with LFO or oscillator signals.

Doesn't need to be real CV conforming to a standard, I'm not playing pitched notes with it. More gentle modulations or FM modulations, of pitch, cutoff and amp etc. If I can find the routing into the analog side I'll add some jacks onto the back of the synth.

I wondered if:

Anyone has a circuit diagram for the Poly800 and/or has tried this.

Knows about the Korg LFOs, are they software or hardware generated on the Poly800?

Also might have details of a line-in mod. I think I could run the line-in as an alternate (or mixed with) the noise source, so that it runs through the filter and MIDI notes/CC can be used to alter the line signal in interesting ways.

Any thoughts or discussion about these ideas, perhaps some of you have tried out these things already. If so I'm really interested to hear about it.

All the best, Louis

Help wanted!

2015-02-09 by Michael Hawkins

Hello HAWK and AtomaHawk fans,

I need your help. I am revamping the HAWK-800 and AtomaHawk web pages. To do that, I would really thank you all for some assistance.

First, I need testimonials from you. They don't need to be long. Two or three sentences (or more if you want to) from you talking about how HAWK or AtomaHawk made your day, helped with a track, made a wonderful sound or made life worth living. Anything you provide will be attributed to your first name only.

Second, I need links to audio files that I can link to that have HAWK or AtomaHawk in them. If you provide a link that uses other synths then a few words about where the HAWK is would be helpful.

That's it. Again, any help you provide will be much appreciated.

/Mike

Re: [korgpolyex] Technical info on Poly800 & analog mods

2015-02-22 by chillipower.uk@...

Hi Mike,

thanks for the response.

I think I'll wait now until Hawk/atomahawk at installed and working, but while I'm in there I'll scope out the circuits for potential mods in this area.

I've ordered a tube of op-amps and a breadboard etc so I can prototype some interfacing, time permitting.

Also got some further mods to do to my sequential circuits synth, so I'll be busy...

BTW, I was considering the simple pot mods for the extreme resonance (moog slayer) but now I wonder if I should, since the 800 will have atoma-hawk added soon. Would both even play nicely. I mean how would the position of the pots and the midi / software derived control voltages interact. Would it make sense to have both, potentially?

Thanks for the help.

All the best, Louis

Re: [korgpolyex] Technical info on Poly800 & analog mods

2015-02-22 by Michael Hawkins

I am bit biased toward not putting the POTS in at all because with the AtomaHawk installed you have full MIDI control over everything. So a controller is all you need to get control over literally everything.

But that's just me.

And yes, putting the POTS in alongside of AtomaHawk does mangle MIDI unless you set the POTS to zero each and every time you want a consistent patch/MIDI experience.

/mike

From: "chillipower.uk@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, February 22, 2015 4:37 AM
Subject: Re: [korgpolyex] Technical info on Poly800 & analog mods

Hi Mike,

thanks for the response.

I think I'll wait now until Hawk/atomahawk at installed and working, but while I'm in there I'll scope out the circuits for potential mods in this area.

I've ordered a tube of op-amps and a breadboard etc so I can prototype some interfacing, time permitting.

Also got some further mods to do to my sequential circuits synth, so I'll be busy...

BTW, I was considering the simple pot mods for the extreme resonance (moog slayer) but now I wonder if I should, since the 800 will have atoma-hawk added soon. Would both even play nicely. I mean how would the position of the pots and the midi / software derived control voltages interact. Would it make sense to have both, potentially?

Thanks for the help.

All the best, Louis