MATRIXSYNTH: synth guts


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

Thursday, April 24, 2025

Akai S900 MIDI Digital Sampler (1986) /// SERVICED + UPGRADED

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


via this Reverb listing

Pics of the inside below.

"The power cable is the original (rare).
The floppy reader has been removed, and replaced by a new Gotek just for the sale, coming from CPmagneticmedia UK (80 €). It is just perfectly fitting, and solid.

Gotek is a game changer. I decided to replace because the floppy reader was not always responsive.
Now you have 4 user banks of 500 slots each + the possibility to organize your data on 16 Go USB key + some installed Akai Libraries + last version system and a screen to read your file names.

See the complete manual online, here is a short list of features I am enthusiastic:

12 bits sampling 7.5-40kHz.

analog low-pass filter
3U format rack
backlight screen
super easy navigation ansy edit
individual transposing + general tuning
velocity sensitive + aftertouch behavior
MIDI in (16) / out
8 voices polyphony and separate outputs
According AKAI themselves, the S900 is their first professional sampler. I confirm the engineering and build quality is superior to other models I owned (S700, S1000 and S1100)."

Akai S1000 MIDI Stereo Digital Sampler (1988) /// SERVICED w/SCSI Card + Floppies

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


via this Reverb listing

Pic of the inside below.

Wednesday, April 23, 2025

Oberheim OBMx Restarting issue - Longer Repair Video


video upload by South London Repair

"Oberheim OB Mx Restarting issue Repair
We try to repair this and restore to original glory."

Views of the individual voice boards.

National Panasonic RD-9844



No listing for this one, just a few pics in via M Me, including one of the inside.

You can find a demo of one in previous posts here.

Tuesday, April 22, 2025

Roland RS-09 Synthesizer Repair


video upload by gstormelectro

"Audio + Video by G-Storm Electro c. 2025

Today I am going to service a Roland RS-09 having some issues. I'm going to
address the tactile button actuator assembly
troubleshooting the dead button panel circuit
address some metal panel rust
replace some felt dust filters for fader pots
deal with the rickety plastic rivet fasteners for the front panel.
Lots of fun stuff.

0:00 Introduction and Symptoms
0:57 Teardown
2:40 Dead Button Diagnosis
4:31 Tests
5:12 Button Actuator Assembly
6:23 New Felt Dust Filters for Slide Pots
7:33 Rivets, Chassis Rust, Final Test

Be sure to check out my cool eurorack modules I make in my Reverb Store
REVERB https://reverb.com/shop/gstormelectro
MUSIC https://gstormelectro.bandcamp.com/
BLOG http://gstormelectronica.blogspot.com/
LISTEN/DOWNLOAD http://soundcloud.com/gstormelectro

Saturday, April 19, 2025

E-MU Systems SP-12 Turbo 8-Voice Drum Sampler

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


via this Reverb listing

Pics of the inside below.

Dynacord Percuter - 8 tracks Digital Drum Computer + 8 cartridges & Dynacord P20 + 5 cartridges

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


Percuter via this Reverb listing

P20 via this Reverb listing [demo here]

Pics of the inside below.

You can find a few demos of a Percuter in previous posts here.

"The Dynacord Percuter is a simple drum module that lets you trigger 8 sounds with pads or sequencer. Very basic features, only a pan and sensitivity control for each channel, as well as independant outputs, and a master stereo output and headphones outputs. There is a cool global pitch control though.

And of course the real nice feature is the ability to change cartridges and thus change sounds as you like. They were many cartridges made and their sound quality is extremely good, in the league of the Linn Drum, Oberheim DMX and such, if not better.

Unit was cleaned and checked and It's fully working and response well to trigger pulses.
8 cartridges are included and they build a full drum kit (a ride or crash could be nice though)

- 111001 Electrified Bass 2
- 111020 Natural Snare 8"
- 111002 Electrified Snare 2
- 111004 Electrified Tom 1
- 111005 Electrified Tom 2
- 111006 Electrified Tom 3
- 111047 Accent Hi Hats Cymbal
- 111048 Closing Hi Hats Cymbal

Please note that P20 and Percuter sound roms are the same (nature snare for instance) they are totally different sounds. The Percuter sounds are 8 bits and the P20 are 16 bits I think. Samples are brighter and longer."

NDK Vintage Rhythm Machince

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


via this Reverb listing

This appears to be the first one to be featured on the site. You can find additonal NDK creations in previous posts here.

Pics of the inside below.

"This nostalgic drum machine is for sale due to studio downsizing. Probably one of the first .

One example is said to be in the German museum.

It is fully functional and still looks quite fresh.

A piece of plastic is missing from 2 gray toggle switches at the front.

All the capacitors have been replaced so that it runs without any background noise.

Very organic, powerful sound, produced by coils and germanium transistors, among other things.

230V

Width: 60 cm, depth: 28 cm Height: 9 cm"

Thursday, April 17, 2025

Tubbutec MC-2oh2 Modded Roland MC-202

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


via this Reverb listing

Pics of the inside below.

"Classic machine, newly and comprehensively pro restored and serviced, upgraded with the top-of-the-line Tubbutec MC-2oh2 High Res Mod, and in perfect working order. The Tubbutec 2oh2 Mod stretches the capabilities of the machine vastly beyond what the original machine is capable of, and also integrates MIDI I/O, while retaining the original sound. See listing video below for more details. Compatible power supply included.

Wednesday, April 16, 2025

Linn Electronics LinnDrum LM-2 Drum Machine w/ Forat Midi Kit

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


via this Reverb listing

Pics of the inside below.

Additional SYNTH CITY Listings

"1980s Linn Electronics LinnDrum LM-2 w/ Forat midi kit professionally installed. Works and sounds fantastic aside from it's cosmetic wear/age. Includes AC power cable.

Service notes:

-Rebuilt 5vdc supply PCB and capacitors
-Replaced electrolytic capacitors on CPU and panel PCBs
-Cleaned all controls and faders"

Saturday, April 12, 2025

Original R.A. Moog 904-A Low Pass Filter

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


via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

Pics of the inside below.

"One of the classic modules of all time, and in its original R.A. Moog incarnation, dating from January (or possibly November) 1969. This example has a 'Bypass' switch mod. This looks very much like a factory modification requested by the original buyer - the style of switch and the black Dymo label seem exactly what Moog would have used at the time. Bought by the current owner in 1999, with light use in a smoke-free home studio. Working well. At some time in the past this actual module was sent to Paul Schreiber to help him design the MOTM 940, and Paul calibrated it to self-oscillate correctly. Situated in the USA but light enough to send economically worldwide."

Ultra-rare Waldeck 70s US Synth

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


via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

Pics of the inside below.

"One of the rarest synths ever - this one is serial number 7 out of about 10 that were built. They were designed in the late 70s by Steven Waldeck, professor at the Art Institute of Chicago. Although there are so few of them there is a good deal of information gathered at the excellent matrixsynth site: https://www.matrixsynth.com/2016/05/more-info-on-vintage-waldeck.html?m=1 We had this example imported from the USA with the aim of having Dani at Hideaway do her magic - but sadly she has too many other projects on the go, and could give no idea of how many hours it would take - and how economically viable it would be. She did check it for electrical safety: 'If it was a 240V piece I'd say it would need some serious attention to detail and most definitely grounded - at 120V, I would say at the very least it should be checked over properly and some addition of sleeving/insulating sheet of the mains wiring on the transformer, fuse and switch terminals.' Bear that in mind along with Mark Verbos' honest appraisal of another example from the matrixsynth page, and consider it a fascinating project, inspired by the VCS3 but definitely not a VCS3. Good for sound effects and weirdness, but not accurately pitched notes. Dani's general verdict as it stands: 'This was clearly intended to be aimed more at making sound effects than to be used as a well calibrated and stable musical instrument - the whole thing is extremely drifty with very narrow usable control ranges on the oscillators - there is a fair amount that doesn't work but I still had some fun making some sort of recording with it to mark the occasion.' https://soundcloud.com/hideaway-studio/1978-waldeck-on-the-waldeck/s-2j3HAUd60BE (corrected URL!)"

Friday, April 11, 2025

Beautiful Vintage Columbia Rhythm Box SN 4645

Note: Auction links are affiliate links for which the site may be compensated.
video upload by Vintage Audio Nagoya

"Star Record echo chamber and Vintage Columbia rhythm box demo from Vintage audio Nagoya (space echo)"



via this Reverb listing

Pics of the inside below.

You can find another demo of one previously posted here.

"The cabinet is real wood with beautiful wood veneer. It's a simple compact unit that sounds great. It has an output and a footswitch jack at the rear. The front has two gorgeous aluminum ringed knobs to control volume and tempo and ten choices of rhythms to choose from. I really like Rock 2 but they are all pretty good. You can push down more than one at a time and really lose your damn mind. I cleaned the pots and switches and hit the wood with some lemon oil. It is ready to rock!

The YouTube video is old and of one I sold a few years ago. The video is terrible but gives you an idea of the sounds."

Thursday, April 10, 2025

Vintage Oberheim DMX 8-Voice Drum Machine SN F40805

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


via this Reverb listing

"Mint condition vintage Oberheim DMX drum machine and sequencer. Iconic piece of music history that is truly inspiring to work with. Brand new battery, factory installed DMX memory expansion, three additional sound cards. Works perfectly and sounds incredible."

Wednesday, April 09, 2025

Anvil UNIQUE 80sPercussion Synth NW



via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

Pics of the inside below.

"The rarest drum machine in the world – the Anvil Percussion Synthesiser prototype. As featured in a major (four-page!) Electronics & Music Maker article in the magazine’s June 1985 edition. The Anvil prototype drum machine was intended to offer user-sampling and programmable rhythm sequencing as well as a drum synthesizer section that could be triggered by pads. However the project was perhaps too ambitious and the development money ran out in mid-October 1985 before it could be completed, leaving the Anvil residing in its flight-case in a London basement for 33 years before being tracked down. The Anvil prototype is not currently functional. A final update provided by engineer Roy Gwinn indicated the top board (control panel etc.) had been operational for a year (to October 1985) and was reasonably reliable. The bottom board (sample/synth) software had been able to sample into memory, replay from memory and save/load to floppy disk. The synth section was seemingly nowhere near completion, and some software had not yet been written. This was late-1985, and the Anvil has probably not worked since then. The Anvil has been powered up recently but the 40-character display was non-functioning. The 3.5 inch disk drive appears to be non-functioning. There are various builds of software/firmware on 12 EPROMs, some of which are populated on the two boards (PR for top board, BB for bottom board), along with two BIOS EPROMs. One early build EPROM (BB) has had a pin repair, and the other has a missing pin altogether. Some EPROMs have been confirmed as having data on them, and two have been copied in a limited (unsuccessful) attempt to get some life out of the Anvil’s top board. The internal battery has recently been removed from the unit. The auction includes the Anvil, the now-external/separate XLR-XLR input 240V mains power supply (with original UK plug), original Bulldog flight-case, the EPROMs, the schematics it came with (which in some cases differ from the current internal layout), a faded computer printout of the menu commands and final summary of work outstanding (16/OCT/85), and a unique (copy 1 of 1) professionally printed Preliminary User Manual written by the current owner collating all the paperwork, user guide, scans of schematics and his own personal full-colour photographs. CAUTION: PROTOTYPE – Should only be powered up by a suitably qualified electrical technician under close monitoring. The Anvil will require significant work to be restored. Weight: 22.3kg in flight-case. Dimensions 68cm wide by 43cm deep by 21cm high (in flight-case)."

Roland's Last Fully Analog Drum Machine - The PB300 Rhythm Plus

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


via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

Pic of the inside below.

"Greetings everyone and hope you are having a lovely day. Im putting up for sale this rare very last member of Roland's fully analog drums era... 42 years ago. Instrument itself is in pretty good condition (few minor bruises and scratches, nothing major) and actual drum machine works perfectly (I cannot confirm the other features like chord or bass, since they are active only in cooperation with Roland HP keyboards). Also a sidenote, since it is a very early midi instrument and mainly designed to work with mentioned keyboards, midi works as clock in/out or start, but doesn't allow to trigger individual drums or accent. Unit was originally for Japanese 100V and has been internally switched to 240V and while I was at it, I have replaced power supply filtering capacitors with new ones for good measure. Thank you all the best."

Tuesday, April 08, 2025

Vintage Heathkit Audio Scope AD-1013 Quadraphonic Oscilloscope and Oscillator (1970's)

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


via this Reverb listing

Pic of the inside below.

"Heathkit AD-1013 Quadraphonic Oscilloscope | Rare 1970s Vintage | Fully Functional & Beautiful

Up for sale is a rare and stunning Heathkit AD-1013 quadraphonic oscilloscope from the 1970s. This piece is fully functional and in remarkably clean condition, especially considering it’s over 50 years old.

The AD-1013 is a unique vintage unit designed for visualizing sound in both stereo and 4-channel quadraphonic modes—perfect for adding immersive, retro visuals to your synth setup, studio, or hi-fi system. It also features a built-in sine wave oscillator (20Hz to 20kHz), making it useful for testing or generating signals right out of the box.

Functionally:

• All features tested and working flawlessly

• Bright, sharp CRT trace

• Stereo + quadraphonic display modes

• Built-in sine wave generator (20Hz–20kHz)

Cosmetically:

• Front panel is clean and vibrant with no major wear

• Chrome accents are shiny with only minimal spotting

• Original knobs are in fantastic condition

• Wood cover has a few light marks but is smooth and attractive

• Reticule and brand sticker are bright and intact

• Black side panels complete the sleek vintage look

This is an incredible and rare unit that delivers both function and serious retro vibe. Whether you’re after vintage test gear, synth visuals, or a killer display piece for your studio, the AD-1013 is the real deal."

Saturday, April 05, 2025

EMS Synthi A with Robin Wood mods, mint

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


via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

Friday, April 04, 2025

Yamaha GX1 w/ Speakers, Programmers & MIDI+

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


via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

"A GX1 is an iconic instrument in any condition, but this one has had the benefit of Colin (Sequentix) Fraser's close attentions over many years. It was bought by Richard James [Aphex Twin] at VEMIA many years ago from Mickie Most's studio. It spent some years in his studio, until it was transported to Colin and eventually to his studio in Berlin, with the principal aim of getting it 100% working again and installing MIDI.

It is complete, with the main console, bench, pedals, two massive speakers, two programmers, and all cabling.

Working order: after some painstaking work at the Sequentix studio it is in full working order as envisaged by Yamaha all those years ago. The two original programmers attach to the Tone Board (patch CV controller) for the Solo keyboard. That board connects on an internal loop to the other manuals, so the programmers can be assigned to any manual for patch editing.

Under the surface there has been an incredible amount of work from Colin: he is in the process of producing a preliminary brochure for his MIDI retrofit, which makes fascinating reading and shows the depth of his exploration of the GX1's architecture - and his huge ability to problem-solve and create new possibilities as well. This brochure would of course be included with the GX1, along with all other literature available. It can also be emailed to prospective buyers on request via Peter Forrest.

At present the polyphonic manuals have full MIDI control. The Solo and Pedal manuals have external CV input Colin has been driving from Cirklon CV outputs. The Rhythm machine has external trigger inputs added, and they are being controlled by a Cirklon D-mux drum trigger module.

Extras: there are a lot of further permutations that could be arranged direct with Colin after the auction. This would depend on the new owner's wishes. For instance one person might want the GX1 as original as possible, and another might want bells and whistles - Colin has designed and prototyped a programmer for the extended sound capabilities he has envisaged, and if required, could extend the MIDI capabilities to the bass pedals.

Cosmetic condition: please see the photos. It is generally in gorgeous condition. The louvred flap on top of the keyboard seems to have some paint damage on the two inner sections, but that looks simple to remove to respray if necessary.

Transport: this is not as daunting as you might imagine. Colin has devised an excellent system for moving it, so that either transporting it by road or crating it for air or sea shipment will be well practicable and safe.

Extras: if the new owner is tempted by Colin's possible add-ons, such as his improved additional Sequentix GX1 Programmer, MIDI bass pedals, or other add-ons, these would be negotiated separately directly with him after the main auction payment."

Adventures in Audio - E Mu Proteus 1 Plus


video upload by Manitou Productions

"Adventures in Audio looks at the E-Mu Proteus 1 Plus Orchestral, a MIDI synthesizer module from 1992. This unit needs a new internal battery, but there are still a few sounds lurking in the RAM. Let’s investigate!

Chapters:
0:00 Rudely interrupted
0:21 Titles
0:28 Intro
0:48 The internal battery
2:29 The Musicstar MIDI controller
3:16 Interlude: hooking up all the things
3:53 Power on & first sounds
4:49 Searching for 'ghost patches' in RAM
10:25 We reach the patches in ROM
11:13 Phantazia!
12:16 Outro
13:28 Ivy's corner

Featured music: The Manitou - The Glow of Screens"

Inside an E-Mu Proteus.
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