Note: Auction links are affiliate links for which the site may be compensated.
via this auction - learn how to sell on eBay here
"Here are the mods:
-Fresh lithium battery and socket install for voice memory (you won't have to change it for another 20 years!)
-Moog Slayer Cutoff/Resonance mods - (allows you to control the cutoff and resonance manually, just set max resonance to 11 in presets)
-FM Modulation mod (white knob)
-12/24db filter switch
-Audio input (you can run audio through the filter and also use the onboard delay)
-Blue LED numbers
-Internal power supply rebuild (replaced all regulators-- power stable)
There's a reason they call the mod the Moog Slayer!.."
Showing posts sorted by relevance for query Moog Slayer. Sort by date Show all posts
Showing posts sorted by relevance for query Moog Slayer. Sort by date Show all posts
Sunday, September 08, 2013
Saturday, December 31, 2011
Tuesday, November 19, 2013
Korg Poly-800 played through Moog Sub Phatty
Published on Nov 19, 2013 msix Anthony·1 video
"A quick little video to demonstrate some of the sonic possibilities of substituting Korg Poly-800's filter with a Sub Phatty. Not a well prepared or imaginative one, just to give you the taste of this idea.
Poly-800 is sending MIDI to Sub Phatty to trigger it's gate and envelope and retrigger the LFO. Thus Sub Phatty becomes a natural extension to Poly-800 and provides it's multi-pole filter and multidrive circuit for polyphonic use.
Intro/outro music: https://soundcloud.com/messier6/ep-funk"
via Anthony Alfimov on The MATRIXSYNTH Lounge
On a side note, there are some notes there on the Poly-800 via Josh Nursing: "The Poly-800 filter is only limited by the lack of circuitry and control knobs in the Poly-800. It's actually a very powerful and fantastic-sounding filter once you mod the Poly-800, with 12/24dB/oct switchable mode, realtime cutoff and resonance. The actual limitations aren't in its filter but in its oscillator section..." You can find info on the Moog Slayer Mod here. They do come up pretty often on the site as you can see here. Below is a video I missed. Be sure to also see the FrankenKorg 800 Demo here.
Korg Poly-800 Moog Slayer Mod + Switchable Filter
Uploaded on Jul 20, 2011 yashnu·83 videos
Super high resonance right after :30. Watch your speaker levels.
"Synth DIY. Real-time Cutoff and Resonance, with switchable filter mode"
"A quick little video to demonstrate some of the sonic possibilities of substituting Korg Poly-800's filter with a Sub Phatty. Not a well prepared or imaginative one, just to give you the taste of this idea.
Poly-800 is sending MIDI to Sub Phatty to trigger it's gate and envelope and retrigger the LFO. Thus Sub Phatty becomes a natural extension to Poly-800 and provides it's multi-pole filter and multidrive circuit for polyphonic use.
Intro/outro music: https://soundcloud.com/messier6/ep-funk"
via Anthony Alfimov on The MATRIXSYNTH Lounge
On a side note, there are some notes there on the Poly-800 via Josh Nursing: "The Poly-800 filter is only limited by the lack of circuitry and control knobs in the Poly-800. It's actually a very powerful and fantastic-sounding filter once you mod the Poly-800, with 12/24dB/oct switchable mode, realtime cutoff and resonance. The actual limitations aren't in its filter but in its oscillator section..." You can find info on the Moog Slayer Mod here. They do come up pretty often on the site as you can see here. Below is a video I missed. Be sure to also see the FrankenKorg 800 Demo here.
Korg Poly-800 Moog Slayer Mod + Switchable Filter
Uploaded on Jul 20, 2011 yashnu·83 videos
Super high resonance right after :30. Watch your speaker levels.
"Synth DIY. Real-time Cutoff and Resonance, with switchable filter mode"
Sunday, August 07, 2011
Korg Poly 800 Moog Slayer Mod Doth Not a Moog Maketh
via Ununseptium warehouse where you'll find the full post.
"For anyone unfamiliar with this manoeuvre, it involves tapping into a couple of variable resistors on the Poly 800's motherboard and routing them to a pair of potentiometers, which should be fitted onto the synth's outer casing, to control the filter cutoff and resonance. Here's a link to the destructions." Note that is a link to the Moog Slayer Mod instructions and not Ununseptium warehouse's post.
P800 post mod 4 by ununseptiumwarehouse
Thursday, August 12, 2010
Korg Poly-800 Synthesizer with many mods
via this auction
Monday, April 28, 2014
How To Instructions on Korg Poly 800 Moog Slayer Custom Modded Analog Synthesizer Keyboard
Published on Apr 27, 2014
"A video showcasing the Moog Slayer mod for the Korg Poly 800 analog synthesizer. You can achieve amazing results with just simple tools and basic soldering skills.
Details of the custom synthesizer mod can be found here: http://synthmod.net/korg/moog_slayer/
http://synthmod.net/korg/fm800/
More details:
http://www.strellis.com/poly800.shtml
Background music is Washed Out - Paracosm (2013)"
Sunday, November 25, 2012
Korg Poly800 Synthesizer Keyboard with Hawk800 Mods & More
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
"Korg Poly800 Mark 1 Synthesizer
with loads of mods making an extreme uber synth with full MIDI spec and loads of new parameters:
The knobby hardware mods were professional installed by Circuitbenders.co.uk:
The "Moog slayer" mod which allows extreme filter resonance and manual control: Cutoff knob, Resonance knob, 12/24db switch.
The "FM800" mod : Source switch, FM Modulation depth knob
Audio Input: Level Knob, Path switch, Filter CV socket.
Hawk800 and Atomahawk boards both installed with all these extra features:
full MIDI spec whereas the original Poly800 had none.
Loads of new parameters: 4 LFOs, many LFO shapes, masses of modulation routings possible, free running or not.
Flash memory so no internal battery required.
7 sequencer memories (originally 1).
MIDI velocity sensitivity.
Moog Slayer and FM800 mods also included so they can be MIDI controlled.
Portamento Mono mode.
4 patch banks
and much much more.
All these mods turn the friendly Poly800 into an extremely versatile and deep synthesizer.
The synth itself is in good condition with the usual minor scratches of something this age. Supplied also is a printed Poly800 manual (not original) and Hawk800 manual, plus PSU."
via this auction
with loads of mods making an extreme uber synth with full MIDI spec and loads of new parameters:
The knobby hardware mods were professional installed by Circuitbenders.co.uk:
The "Moog slayer" mod which allows extreme filter resonance and manual control: Cutoff knob, Resonance knob, 12/24db switch.
The "FM800" mod : Source switch, FM Modulation depth knob
Audio Input: Level Knob, Path switch, Filter CV socket.
Hawk800 and Atomahawk boards both installed with all these extra features:
full MIDI spec whereas the original Poly800 had none.
Loads of new parameters: 4 LFOs, many LFO shapes, masses of modulation routings possible, free running or not.
Flash memory so no internal battery required.
7 sequencer memories (originally 1).
MIDI velocity sensitivity.
Moog Slayer and FM800 mods also included so they can be MIDI controlled.
Portamento Mono mode.
4 patch banks
and much much more.
All these mods turn the friendly Poly800 into an extremely versatile and deep synthesizer.
The synth itself is in good condition with the usual minor scratches of something this age. Supplied also is a printed Poly800 manual (not original) and Hawk800 manual, plus PSU."
Sunday, February 26, 2012
Modified Casio HT-700 with Drum Pitch and Moog Slayer Filter Mod
"modified Casio HT-700 Synthesizer with Moog Slayer filter mods and Drum Pitch mods. The filter mod is MUCH better than the one done on the wimpy Poly 800, and the drum pitch is insane! The filter mod allows you to adjust Cutoff and Resonance in REAL time, and the VCA is analog."
Friday, December 18, 2020
Korg Ex-800 poly analog synth with Hawk and Moog slayer upgrade
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
"Here is vintage Korg Ex800 synth upgrade with the Hawk 800 and Atomahawk (moog slayer) mod. Serviced and professionally installed."
via this auction
"Here is vintage Korg Ex800 synth upgrade with the Hawk 800 and Atomahawk (moog slayer) mod. Serviced and professionally installed."
Monday, June 19, 2017
Korg EX-800 Polyphonic Desktop Synth (Filter Mod + FM [Moog Slayer] w/ PSU)
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
"Vintage Korg EX-800 polyphonic MIDI desktop synthesizer. It features an analog filter and chrous modifying 8 DCOs, 2 LFOs, and 3 Envelope Generators. The unit also contains a built-in sequencer. In addition to the stock functionality, the Moog Slayer filter cutoff/resonance mod has been added as well as a frequency modulation knob."
via this auction
"Vintage Korg EX-800 polyphonic MIDI desktop synthesizer. It features an analog filter and chrous modifying 8 DCOs, 2 LFOs, and 3 Envelope Generators. The unit also contains a built-in sequencer. In addition to the stock functionality, the Moog Slayer filter cutoff/resonance mod has been added as well as a frequency modulation knob."
Sunday, October 09, 2011
Korg Poly-800 with Moog Slayer Mod & Original Box
via this auction
"For full details check out [this link] which gives technical information and some idea of just what the modification entails."
Two older videos linked in the auction below.
korg Poly 800 Synth with Moog Slayer Mod
YouTube Uploaded by AlexisG73 on May 13, 2007
Korg POly 800 mod
Uploaded by abertronic on Feb 4, 2009 -
abertronix on eBay (RSS)
Note the Poly-800 in this video also has the FM mod which is not installed in the auction above.
Sunday, May 26, 2013
Korg Poly800 with Original Blue Gig Bag & Moog Slayer Mod
Note: Auction links are affiliate links for which the site may be compensated.

via this auction
"This particular example has had the so-called 'Moog-Slayer' mods installed. This means there is a dedicated knob for the analogue filter cut-off and resonance. It makes a huge difference to the hands-on operation of the synth.
It also comes complete with it's original padded soft case, in a very fetching 1980's baby blue and orange."
cE9s4PsOsIBRooM1vr8Q~~60_57.JPG)
via this auction
"This particular example has had the so-called 'Moog-Slayer' mods installed. This means there is a dedicated knob for the analogue filter cut-off and resonance. It makes a huge difference to the hands-on operation of the synth.
It also comes complete with it's original padded soft case, in a very fetching 1980's baby blue and orange."
Friday, October 03, 2014
Korg Poly 800 with Moog Slayer and other filter mods plus a built in BSIAB II
Uploaded on Jun 29, 2011 sizzlemeister
"Korg Poly 800 with Moog Slayer mod, Filter Frequency Modulation mod, 12/24 db Filter switching, and a BSIAB II grafted into the former chorus circuit. I picked up this Poly 800 at a yard sale and it was in very bad shape, so I gave it bath and fixed it up. It needed the power section rebuilt and some other work, plus the joystick knob was missing so I replaced that. I added an internal battery for the memory."
Wednesday, March 16, 2011
KORG Poly 800 with Moog Slayer Mod & Blue Display
korg Poly 800 Synth with Moog Slayer Mod
YouTube Uploaded by AlexisG73 on May 13, 2007
Saturday, April 06, 2013
Korg EX-800 w/ MOOG SLAYER and FM-800 Mods SN 001480
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
"The Moog Slayer Filter mod allows the user to alter the cutoff frequency and resonance with realtime control. This adds incredible lows and ultra highs to your sound. Be warned, it can scream and may cause speaker and even ear damage. Please use at your own responsible risk. Not that it will hurt you, but I feel that fair warning is appropriate.
The FM-800 mod adds a touch of modulation to the sound which is adjusted by its own pot. Adds an interesting flavor if I do say so myself."
"The Moog Slayer Filter mod allows the user to alter the cutoff frequency and resonance with realtime control. This adds incredible lows and ultra highs to your sound. Be warned, it can scream and may cause speaker and even ear damage. Please use at your own responsible risk. Not that it will hurt you, but I feel that fair warning is appropriate.
The FM-800 mod adds a touch of modulation to the sound which is adjusted by its own pot. Adds an interesting flavor if I do say so myself."
Thursday, December 26, 2013
Siel DK70 Analog Synth with Moog Slayer mod
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
"A previous owner installed the 'Moog Slayer' filter mod, which adds knobs for real time control over filter parameters (see photos). This is similar to the mods often installed on the Korg Poly-800 and gives you some hands-on control that would usually be lacking. It's a subtle effect but very useful on a synth that otherwise would be difficult to program..."
via this auction
"A previous owner installed the 'Moog Slayer' filter mod, which adds knobs for real time control over filter parameters (see photos). This is similar to the mods often installed on the Korg Poly-800 and gives you some hands-on control that would usually be lacking. It's a subtle effect but very useful on a synth that otherwise would be difficult to program..."
Saturday, November 06, 2010
White Modified Korg Poly 800 Diabolical Moog/CV VCF
via this auction
Small pics unfortunately.
"Modified Korg Poly 800 by Diabolical Devices with custom paint job. The poly 800 is a great sounding synthesizer with an analog VCF/ Filter. This synthesizer now has several modification installed that majorly expand the capabilities of the filter.
Moog/Slayer mods- adds hard wired controls for VCF cutoff and resonance.
VCF Audio input with level control-Allows you to process external audio through VCF, VCA and Chorus.
VCF CV input- Controls VCF cutoff with external CV source.
Sunday, May 04, 2008
Korg Poly 800 with filter-control-knobs
YouTube via moogfreak. I'm guessing this is the MOOG Slayer Mod.
"Hello. In this video I will show you my selfmodified Korg Poly 800. I have added two knobs for filter-control - one for the cutoff and the other one for the resonance. On the back of the synth you can see a switch, which activates the new knobs. In this video you can see and most important hear how it works. The sequence in the beginning and at the end I have programmed on the Poly 800`s build-in sequencer. In the middle I`ve tried to play "Emerson, Lake & Palmer`s" "Aquatarkus", which Keith Emerson has played on his large Moog Modular. For this sound you need three oscillators per note, so I have done this with the Poly 800`s "chord memory"-function. As you can hear - it works very well. But I`m not as good as Keith. :-) Please excuse the pumping compressor/limiter from my videocam."
Saturday, July 24, 2010
KORG POLY-800 with Slayer Filter Mod
"THIS POLY-800 IS TOTALLY DIFFERENT, THE FILTER MODIFICATION AND MOOG SLAYER TAKE OUT AN INCREDIBLE SOUND. THIS HAS ANALOG FILTERS WITH DCO (DIGITALLY CONTROLED OSCILLATORS) THIS SYNTH IS GREAT FOR PADS, FAT BASS AND VINTAGE SOUNDS."
Monday, May 29, 2017
Reverse Keys Korg Poly 800 w/ Slayer Mods
Note: Auction links are affiliate links for which the site may be compensated.
via this auction
Several non-responsive keys fixed
Button contacts cleaned
Memory battery replaced (worth noting the original battery was still in here, so it has lasted about 30 years!)
Factory patches restored via tape (notoriously difficult to get right on this model - I've saved you the trouble!)
The 'Moog Slayer' mod has been added - giving you real time control over the filter and resonance
FM mod - giving you frequency modulation from the VCF (useful on some patches, horrible on others!)
via this auction

Button contacts cleaned
Memory battery replaced (worth noting the original battery was still in here, so it has lasted about 30 years!)
Factory patches restored via tape (notoriously difficult to get right on this model - I've saved you the trouble!)
The 'Moog Slayer' mod has been added - giving you real time control over the filter and resonance
FM mod - giving you frequency modulation from the VCF (useful on some patches, horrible on others!)
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© Matrixsynth - All posts are presented here for informative, historical and educative purposes as applicable within fair use.
MATRIXSYNTH is supported by affiliate links that use cookies to track clickthroughs and sales. See the privacy policy for details.
MATRIXSYNTH - EVERYTHING SYNTH