MATRIXSYNTH: synth guts

Showing posts with label synth guts. Show all posts
Showing posts with label synth guts. Show all posts

Monday, September 14, 2026

ROM EXPANSION – For EPROM Drum Machines by DUCKTRONIC



DUCKTRONIC has made a ROM Expansion currently compatible with Oberheim DX and Linn drum machines. You can find the user manuals for each on a Google drive here.

The following is the intro in the DX manual: "The ROM EXPANSION extends the Oberheim DX with 104 sounds, most of which originate from the early 1980s. This makes it possible to recreate the sound of drum machines from that era. It is also possible to save custom-assembled soundsets and load them again at a later time.

Installation requires the CONTROL BOARD with the "Sound Control" software, the CONTROL PANEL, and six EPROM BOARDS with EPROMs. If only individual instruments are to be modified, fewer EPROM BOARDS are required accordingly.

Installing the ROM EXPANSION does not require any mechanical modifications or irreversible changes. The original state of the Oberheim DX can therefore be restored at any time."

You can find a YouTube playlist with demos here.

Tuesday, September 08, 2026

1983 Roland MKS-80 Super Jupiter Vintage Synthesizer Module 8-Voice Poly Synth SN 460599

Note: links to listings are affiliate links for which the site may be compensated.


via this eBay listing

Pics of the inside below.

Thursday, September 03, 2026

Yamaha RX21 - A Vintage Drum Machine that Promises Realism


video upload by Manitou Productions

"In 1985 Yamaha released the DX21 Digital Rhythm Programmer, promising the drum sounds were 'indistinguishable' from the real thing. We know better, don't we? That doesn't mean we can't enjoy the RX series of drum machines for what they are: fun and simple beat boxes that still have something to offer in 2026. Let's go!"

Chapters: 0:00 We don't want it that fast! 0:09 Titles 0:17 Intro 0:33 A quick look at the manual 2:22 Wedge shaped 2:36 Ins and outs 3:30 Adapter 4:04 Let's turn it on! 4:48 Sounds! 5:36 Some patterns 6:25 Tempo 8:41 Let's open it up! 9:42 Battery test 10:00 The button matrix 10:56 Cleaning the carbon pads 13:39 Partial reassembly 14:05 The circuit board 14:59 Adjusting volumes 16:52 Recording a pattern 20:27 Playing it through the Rev7 Reverb 23:17 Outro 24:22 Ivy's Corner

Tuesday, September 01, 2026

EMS 256 Sequencer repair Part 5 Finale


video upload by Really Nice Audio

All parts

"Join me in this final video restoring this EMS 256 sequencer.

Watch me fumble around until I finally get the I/O scaled correctly!

Thanks to PCBWay for making the extender boards https://www.pcbway.com

This sequencer is part of the Pete Townshend Studio ay the University of West London.

https://www.uwl.ac.uk/study/study-fac..."

Wednesday, August 26, 2026

Soviet RITM2 Repair


video upload by Really Nice Audio

"Join me on this nice repair of a RTM2 soviet era synthesiser.

The music in the video is from my ATMOS album 'Height Supremacy'.
This track has plenty of my own RITM2 on it.

When the power supply fails a great substitute is the Velleman project
https://whadda.uk/Item/velleman-k8042...

And if you experience the pitch gong flat no matter how you set the calibration, adding half a volt to the positive power rail can really help."

Sunday, August 23, 2026

1988 Studio Electronics MidiMoog Vintage Mini Moog Model D MIDI Analog Synthesizer

Note: links to listings are affiliate links for which the site may be compensated.


via this eBay listing

"1988 Studio Electronics MidiMoog Analog Synthesizer

100% All Original MIDI MiniMoog Rack Mount Synth

Factory MiniMoog Model D Circuit Board!

For your consideration is this vintage 1988 Studio Electronics MidiMoog analog synthesizer. This excellent 100% all original example is in perfect working order. It appears to be a pre-production example, having never been adorned with a serial number placard. Not many were produced, but the Studio Electronics MidiMoog features an actual Moog Model D circuit board within!"

Pics of the inside below.

Friday, August 21, 2026

Sequential Prophet VS With Controller Rackmount 8-Voice Polyphonic Synthesizer SN 0275

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

"With its controller, and exceedingly rare cartridges, this Prophet VS is a very clean example of a pretty hard to come by synthesizer. It was recently given a clean bill of health by one of our in house techs, and it sounds excellent."

Sunday, August 16, 2026

EMS 256 Sequencer Repair Part 4


video upload by Really Nice Audio

All parts

"In this episode we edge closer to getting this legend back in full working order. Now I have my extender cards I can probe the circuits and start debugging the rest of the faults.
After checking around the recirculation circuits and shift registers I decided to remove the 'Time Extender Board'. Now it plays back recordings!
I have to do some more research on this board in the next episode.

Thank you
https://www.pcbway.com
for making the extender boards. They were perfect!

This EMS 256 is part of Pete Townshend synth collection at
https://www.uwl.ac.uk/study/study-fac..."

Friday, August 14, 2026

Roland Super JD-990 Sound Module SN ZE50179 w/ SR-JV80-04 Vintage Synth Expansion Board

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

"With expansion on board, and some truly wonderful sounds at your fingertips, this Super JD has been tested and is working great."

Tuesday, July 28, 2026

KORG KLM-1884 PBS-Tri Sampler Flash ROM for Korg Trinity Series

Note: links to listings are affiliate links for which the site may be compensated.


via this listing

Additional Perfect Circuit listings

Korg MOSS Board EXB-Moss DSP synthesizer expansion for Triton

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

"Excellent condition. Works perfectly.

MOSS board for Triton and Korg KARMA

Removed from Triton Extreme and stored in anti-static pouch as shown."

Sunday, July 26, 2026

Oberheim SEM 1977 via 360 System Spectre

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

Pics of the inside below.

"These used to be a somewhat well kept secret, obviously no more. But if you're not familiar with the 360 Systems Spectre, it was a pretty terrible GUITAR synth (slow & choppy tracking) that 360 Systems produced with Oberheim SEMs as the heart of these units.

Sometimes you'll see these listed as being "Converted to full-functioning SEM" but often there's a thing or two that were missed. You have to reconfigure a few jumpers, add a missing coupling capacitor to each envelope generator, add the missing Decay and Sustain controls to the EG on the Amp VCA, replace the input gain resistor for the external input, add shielded wire for the output, change the output impedance resistor and so on. Everything was done to this unit to make it true full-functioning SEM. An original SEM/CPS-1 power supply (recapped) was also installed inside.

I'm also including a 1977 CPS-1 chassis (complete with recapped PSU) with it so if you do find a faceplate, you'll have a complete SEM. My plan was to find or have someone make me an SEM faceplate in the rare black finish. I thought the gray knobs would look killer on the black panel. But tbh, I really liked the portability of the 360 case. Oh well, someone else can enjoy it now. I've used this in my studio for the last 5-6 years. I will miss it but I'm not doing much synth-based music.

-Synth was fully restored 5 years ago with some basic maintenance in the last 2 years

-All electrolytic and tantalum capacitors have been changed

-VCOs & VCF tuned/calibrated

-AC cord was removed from the front and an IEC was added to the rear of the case

-pots and switches were recently cleaned

-Sub OSC ckt. was added (non-invasive, made by Pete's Gear Garage in Sweden, uses 'Guitar' knob in mixer section)

-Each Jack on the bottom row has a function such as Hi & Low outputs, CV & Gate in, Ext. Input, LFO retrig, VCF in and out (for use with modular) and VCF CV.

-I still have the 360 Systems Control board. It was robbed of a few parts but the PSU and the Transpose rotary switch are still on it. If you want it, send me a msg and I'll include it with the sale."

Tuesday, July 21, 2026

Vintage ARP Quadra 2463 Analog Synthesizer & Keyboard SN 24630157

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

Pics of the inside below.

"Tested and Working. This was pulled from a working environment. Please look at all pictures before purchasing, only what is included in pictures is included in sale."

Monday, July 20, 2026

EMS 256 Sequencer Repair Part 2 Re-Cap circuit cards and devising a plan.


video upload by Really Nice Audio

Really Nice Audio EMS 256 Sequencer posts

"What is the likelihood due you think I will get this sequencer fully functional? I am now able to see the memory fill up when using a key input. The hardest thing for me to work out was a strategy for the repair. Considering how old this unit is will I find many broken logic IC's?

It is hoping to play some music in September, let me know your thoughts below.
https://paymentportal.uwl.ac.uk/confe...

This is part of the Pete Townshend Synth Collection at the University Of West London

https://www.uwl.ac.uk/study/study-fac..."

Thursday, July 16, 2026

ARP 2600P V3 (1972–1974) with 3604P Keyboard – Classic Semi-Modular Analog Synth

Note: links to listings are affiliate links for which the site may be compensated.


via this eBay listing

Pics of the inside below.

"ARP 2600P V3 Synthesizer with 3604P Keyboard
Power cable
5 patch cables
Keyboard-to-module cable
Case covers and original manual

Condition:
This unit is previously used and shows normal cosmetic wear consistent with age. It is fully operational, including all oscillators, filters (4012), and modulation sections, and functions as intended."

Thursday, July 09, 2026

EMS 256 Sequencer Repair Part 1


video upload by Really Nice Audio

Really Nice Audio EMS 256 Sequencer posts

"Join me in a quest to get this incredible sequencer back up and running.

It is part of the Pete Townshend Synth Collection at the University of West London
https://www.uwl.ac.uk/study/study-fac..."

SN 6014

Wednesday, July 08, 2026

Roland System 700 Modular Synth Repair | Full Teardown & Service #183


video upload by Synthchaser

"We explore the workings of the ultra-rare Roland System 700 Modular Synthesizer as we repair and service one of only 40 systems ever made!

🌐 Find me here:
https://synthchaser.com/"

Tuesday, July 07, 2026

Yamaha DX100 Restoration


video upload by Runningonair

"In this video I restore a Yamaha DX100 keyboard and replace the screen with a modern illuminated blue display."

Music/Support:

https://runningonair.bandcamp.com/

https://open.spotify.com/artist/5fNUf...

https://paypal.me/runningonair?

Tuesday, June 30, 2026

Moog's Extremely Rare Synth- The Minitmoog!


video upload by synthpro

"Hey Guys,

In this video, I take you through the Minitmoog synthesizer. from my understanding this was a one year only model with only a few hundred manufactured.

Thanks for watching!
Jareth"

Sunday, June 21, 2026

EMS Rehberg Logik Analog Synthesizer & Keyboard (Made in Germany)

Note: links to listings are affiliate links for which the site may be compensated.


via this Reverb listing

Pics of the inside and the user manual below. "This edition is rare, and cannot be found anywhere as a set. Made by EMS London, and works differently than the Synthi A, although it appears to be the same. Here is a breakdown of what you get below:

In addition to the power supply, new patch cables as well as the original patch cables (standard mini jack), the lid of the "suitcase synthesis" and the original manual (or textbook) are included.

The modules of the EMS Synthis work perfectly, the overall sound and especially the filter sound very high-quality.

VCO – Voltage Controlled Oscillator • with the vibration forms sine, sawtooth, triangle and rectangle with external control voltage input for pulse width modulation • VCF – Voltage Controlled Filter • Multimode filter with 12 dB slope, low-pass, high-pass, band-pass and phaser • LFO – Low Frequency Oscillator • with the vibration forms sine and rectangle • SRG – Slow Ramp Generator •

with
the vibration form sawtooth • NG
– Noise Generator •
the noise generator offers white
noise • EG –
Envelope Generator (Envelope
Shaper)
• A-D-S-R • RM
– Ring Modulator • INV – Inverter • SL – Slew Limiter (Portamento) • EF – Envelope
Follower • External Audio
Input • Output/Mix
• Control Inputs"

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