MATRIXSYNTH: Search results for ohm_studi_ohm

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Showing posts sorted by relevance for query ohm_studi_ohm. Sort by date Show all posts

Monday, April 24, 2023

family meeting: Roland MRS-2 Promars and Roland Jupiter 4

video upload by ohm_studi_ohm

"Since I just serviced a Promars for a friend of mine I decided to compare it to my JP4.
Both units are fully working, recapped and calibrated. And both are from latter revision with IR3109 filters. Basically they have same motherboard, module board and module control board.

First a quick impro taking advantages of what makes them different: Promars has a second VCO with 2 tuning settings so it can sounds thicker than the JP4, whereas the latter is of course polyphonic and has a builtin arpeggiator and stereo chorus effect.
They share the same CPU and 'compuphonic' technology and have (almost) the same presets.
You can hear when I compare both synths that the presets don't sound exactly the same but this is more a question of calibration and preset values then synth character.
Calibration method are different for the 2 synths and there are slight different adjutements, especially on the filter frequency, width, resonance and hi pass filter setting.
Also i'm quite sure the presets value are a bit different in the JP4 and Promars. Most obvious is the "voice" preset with is one octave higher on the JP4 ! And listening to other presets some a bit brighter on the Promars while other are brighter on the JP4.
But you can observe when I edit the JP4 presets that it's very easy to get the same sound from both unit.

They do get along quite well and their respective particular features make owning the two of them even more desirable."

And some pics via ohm_studi_ohm:

Saturday, March 18, 2023

Jen Synthetone SX-2000

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


Quick demo of a recently serviced and modded Jen Synthetone SX2000 italian mono synth.
CV/Gate and Fiter inputs were added, see the other video where I showcase the synth with external control. (

• Jen Synthetone SX... )
Recorded straight with no FX nor treatment.

The SX2000 is one of my favorite mono synth, I always had at least one in my setup. Just one oscillator but thaks to a ladder filter inspired by the EMS VCS3 it sounds very nice, it can be beasty and funky. Very simple architecture but some nice features like both VCF and VCA enveloppes can be set either in Attack Decay mode, Attack Sustain Release mode or repeat mode, rate being set by the LFO. This alone broadens the sonic range. The added CV/Gate kit (based on the Kentron one) enables this one to be interfaced by sequencers and/or modular synthesizers."

Jen Synthetone SX-2000 externally controlled demo

video upload by ohm_studi_ohm

via this auction

"Synth was serviced:
- fully recapped
- busbar and key contact were cleaned
- faders were cleaned and lubbed
- CV/GATE/Filter kit was added
- full calibration

It is in perfect working condition.
I have to point that the faders are not great on those synths, and though they were serviced they can be sometimes be hard to move. It's because the have a little play on the lever so when you engaged the move sometimes this play brakes them. Nothing dramatic but I just prefer to point it out, it's not Roland SH smooth faders. You just have to get how to grab them and then it's easy.
All the different SX-2000 I own had this issue and no cleaning or lube will ever make them perfect.

Cosmetic wise the synth has some wear but still looks more than decent."

Saturday, October 21, 2023

Programming Crumar BIT99 with MIDI Controller

video upload by ohm_studi_ohm

"This synth is for sale. You can buy it directly ( for 1450 euros or buy it on eBay ( or Reverb [pics captured here]

This is demo mainly to show how easy it is to program this synth thanks to the amazing work Bob Grieb (Tauntek) did by rewritting the firmware and enabling Midi Control Changes messages on this synth.

The only drawback (due to the hardware) is you have to retrigger a note for every change you make on a parameter, except for a few ones that a real time (resonance, DCO and LFO waveshape for instance). Just a minor annoyance compare to the original programming method (which is actually not the worse of that kind).

The BIT99 and BIT01 are very nice sounding and quite comprehensive 6 voice analog synth. They feature 2 DCOs with triangle, sawtooth and pulse waveform, in octave from 32 to 4 and you can combine the 3 waveforms on each oscillator. Dedicate ADSR enveloppes for filter and amp with velocity control, 2 LFOs, noise generator, split or stack possibilities etc

IMO they only lack a mixer for the 2 oscillators, LFO PWM (though you can control the PW with velocity) and a hi pass filter.

But the sound is very nice, I favore it over the Oberheim Matrix 6 for instance. It sits very easily in the mix. Build quality and keyboard are also of upper level."

Wednesday, November 29, 2023

The Ace Tone Rhythm Ace family: FR-1 Full Auto

video upload by ohm_studi_ohm

"Here is a glimpse of the analog drum machine range from japanese manufacturer Ace Tone. Quite popular in the late 60s and early 70s, they were probably the leader in those presets rhythm units at the time before Roland came into the game.

Full analog, only transistors and diodes, no integrated circuit yet.

FR1 and FR2 are basically the same unit. They do sound similar (same PCB) and have the same presets. The main difference is the cancel buttons. On the FR1 you can cancel "bass drum", "cowbell", "claves" and "cymbal", whereas on the FR-2L you can cancel "snare", "claves" and "cymbal".

Of course it is very easy to mod these units and add other mutes buttons, individual levels, outputs etc

The FR20 is quite similar soundwise to the previous ones. The patterns are different, they are fewer but you have 3 "customizable" presets with differents variations of snare and cymbal, thus effectively giving it a wider range of possible patterns, and this time you have cancel for "bass drum", "snare" and "cymbal" which make more sense then the previous ones' choices.

But the main feature of the FR-20 is that it has a built in amp powered speaker cabinet. And it sound loud and deep, it's a great combo. Plus ther is an input so you can plug you organ or synthesizer and play along the rhythm (start stop with foot pedal is possible on all units btw).

The FR6 is quite a different beast. It sounds very different to the other 3, soundwise and in terms of patterns. Sound is brighter, crispier even harsher.

Note all the units where fully recapped so difference in sounds isn't due to ageing component but to design. I don't have the schematics for this one but it's definetly not the same layout. It might have been designed or "inspired" by some other model available at the time. (could be the Roland TR-66 with which it shares many features).

So here is a demo of the first one: The FR-1.

Recorded through a Teisco 120 to add some reverb."

Tuesday, June 20, 2023

Wersi CX5 / german 12 bit drum machine from the 80s

video upload by ohm_studi_ohm

This one is currently listed for sale on Reverb here, and on eBay here. You can find pics from the listings and an older demo posted here.

"Very quick demo of the Wersi CX5 drum machine. Classic 80s 12 bit sounds. There are 26 of them including a analog drum synth sound plus a chromatic timpani mode (!)

Very comprehensive it has 8 analog outputs, MIDI IN and OUT, Tape, Sync and a dedicated connector to plug some pads in order to trigger the sounds.

The video focus on the MIDI control of the unit and as you can see you can easily play the sounds over midi with velocity.

And thanks to the global pitch control it is a great live performance tools in the right hands (oblivously not mine)."

Sunday, November 27, 2022

Vermona ET-3 all transistor East German combo organ

video upload by ohm_studi_ohm

"Here is a quick demo of a recently serviced Vermona ET-3 combo organ. This one is the early model that is 100% transistor (silicon). Later revisions used chipsets.
Very simple and yet quite versatile organ. You can mix 16 / 8 / 4 footages in both formants and flutes voices, with an added low pass filter ("brillant" fader) and a nice vibrato with speed and depth control.
Very clean sounding, much better than most italian ones IMO.
Recorded straight with no eq, fx or treatment."

Friday, August 25, 2023

Crumar Bit99 + Wersi Wersivoice

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

"Quick demo of the Crumar BIT99 i fully serviced. In the frst part i flip through a few patches to let you hear how this one can sound, mainly for bass/lead/keyboards sounds. And in the second part I focus on pads and i run the synth through a custom built Wersi Wersivoice analog triple chorus. As you can hear i can turn the BIT99 into a great string machine and more.
Record with no other FX or treatment.
Pardon my playing, I'm better at servicing these instruments than playing them :-)"

via this auction

"Here is your chance to grab a unique combo in the form of 6 voice analog polysynth and a custom made BBD triple chorus ensemble effect.

The Crumar BIT99 was fully serviced:
- power supply electrolytic capacitors replaced
- voice board electrolytic capacitors replaced
- firmware upgraded with Tauntek one: you can now easily control and program the synth with any midi controller
- keyboard dismantled and contacts and bus bar cleaned
- meticulously calibrated
- panel board and case fully dismantled, cleaned and polished
- custom made real wood side end cheeks

It sounds, plays and looks awesome. It does has some wear and scuffs but it is in great condition.

The Wersivoice was custom built and is a great addition to any synth, analog or digital. It simply can turn anything into a great string machine, and more.
Very simple, no control: sound in sound out. There is a 3 positions switch with ON / MUTE / (true) BYPASS positions.
It runs directly from 230v.
Since it's DIY it doesn't look perfect."

Saturday, February 17, 2024

rare birds: Powertran Transcendent 2000 with sub oscillator mod

video upload by ohm_studi_ohm

"Here is a Powertran Transcendent analog synth I just serviced.
I took the opportunity to make some modifications, mainly adding a sub oscillator circuit.
I used a simple 4024 chipset and routed the -1 and -2 octave outputs to the "noise" volume pot with a 3 positions switch so that I can chose either octave sub or the Noise generator as the source for that pot.
I also made modification to the CV and gate circuit which originally are not the common 1v/octave V-trigger kind.
Now it can be used with any standard CV / gate interface.
And last modification was a lighter one: adding a LFO rate blinking led.
Very nice synth, capable of quite a wide range of sound thanks to dual resonant filter mode (Low Pass / Band Pass), S+H, repeating enveloppe, PWM etc … and now with a sub oscillator :-)

PS: this synth is not unstable in pitch. If you look carrefully you'll notice there is a slight amount of lfo (saw) modulation applied to the OSC pitch almost all the time"

Monday, November 13, 2023

Crumar Multiman S / Orchestrator

video upload by ohm_studi_ohm

"The Crumar Multiman S (Orchestrator) is one of those classic multi instruments of the 70s. 4 sections: bass / brass / piano / strings
Each section (except for the bass) can be assigned left or right of the keyboard with dedicated volume faders and mute switchs.
Brass has a Moog inspired ladder filter with simple AD enveloppe and cutoff and resonance control (resonance can get wild if you want to).
Strings are composed of Viola and Violins, with timbre adjust. It uses a triple chorus based on the TCA350Y BBD chipsets, basically the same as the Eminent String Ensemble.
You have control over the release of the strings (called "sustain" on the panel). This also control the release of the Brass sound.
Piano section consists of Piano and Harpsichord sound. You can control the sustain (again it's the release actually) with a pedal only. Without a pedal plugged in the release is always at its maximum. And the release is common to the bass sound, which by the way sound huge.
And to finish you have a vibrato that affects all the section."

Friday, May 17, 2024

SoundMaster ST-305, Roland Jupiter 4 & Echolette SE251

video upload by ohm_studi_ohm

"Quick impro to demo the Sound Master Stix Programma ST-305 (!) analog drum machine syncing the Roland Jupiter 4 arpeggiator. The Echolette SE251 provides echo/reverb.
The ST-305 is an 80s programmable analog drum machine. Very basic, no sound editing but you get 7 sounds, an accent track, dedicated volume faders and outputs for every instrument.
And the icing on the cake is it can be synced to external gear and/or sync other gear, which is a nice feature (you can use it slaved to a sequencer and in the same time slaving a synth, so it acts as a 'through').
I did not know this one till recently and it was a pleasant surprise."

Klemt Echolette SE-251 tape delay.

via this listing

Pics of the inside below.

"This is quite a rare tape echo manufactured by Dynacord. It seems to be one of the very last tape echo introduced by the brand (with the Echolette Echo 400).
It shares many parts with the Echocord line of delays like motor, pinch roller, heads, oscillator board etc
But this one used op amps instead of only transistors for amp stages (the Echocord Super 76 also already used one op amp for the output stage).

The unit has 2 heads which you can mix with the dedicated pot. Otherwise classic features like input volume, tone, echo send level, echo feedback and echo level.
In the back the original DIN socket enabled output and aux input. In this case you only get the wet signal out of the delay, which is nice in a studio environment.

Unit was fully serviced and modded:
- all electrolityc caps were replaced (except 3 bipolar ones )
- original 4x op amps were upgraded to better one (TL081)
- original DIN socket was replaced by 2 jack sockets, one for the output and one for the aux input. Also a pot was added to attenuate the level for the aux input
- unit was meticulously cleaned
- heads were cleaned, demagnetized and aligned
- unit was calibrated
- tape is new

The unit is in perfect working order and in excellent cosmetic condition."

Thursday, April 18, 2024

Roland Juno 106

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

"First part I demo a few presets and most of the controls.
On the second part I enter test mode and let you listen to the 6 voices filter calibration.
This is a good test to check if your Juno 106 needs calibration. Most of the calibration procedure is dedicated to the filter setting, since oscillators are DCO they won't drift, but the filters can. By entering test mode and selecting bank 3 you basically recall a patch that has filter in self oscillation with keyboard tracking, thus you can easily hear if any of the 6 voices is off. Just play notes in the high and low notes and listen to the pitch (and amplitude). The 6 voices should sound the same, like on this unit. If one or more is way off it's time for calibration."

via this listing

Friday, August 25, 2023

Korg Mini Pops 3 & Korg Mini Pops 7

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

Update: video added.

via this auction

"2 Korg analog drum machines: the Minipops 3 and Minipops 7

Both units were serviced and partially recapped and are working and sounding as they should. Cosmetic the Mini pops 3 is in very good condition. The MP7 has the red lettering for second row of rhythm almost erased and it's missing the Mini Pops sticker. Case is hower in good condition.

Please note these are the Korg (Keio) genuine Mini Pops model, not the Univox SR55 and SR95."

Sunday, May 05, 2024

Hohner String Performer

video upload by ohm_studi_ohm

"The Hohner String Performer was one of the very last effort to release a string synth, in the early 80s I think. This was the only one genuinely manufactured by Hohner. The early ones like the String Melody, StringVox or String Orchestra were italian rebadged ones.
The Performer features 3 strings presets, 1 piano, 1 harpsichord, 1 bass (only on the left part of the keyboard) and a monophonic 'solo' section on the right part of the keyboard only. Just like other 'orchestral' synths like the Crumar Orchestrator/Multiman or the Elka Rhapsody 610 you have individual volume faders for each sound on each side as well as a mute switch per section.
The 'bass' preset overides everything on the left part of the keyboard when selected.
Overall this is one of the most refined string sound you can get, very polished, maybe too polished for some. I like it a lot, I find it very cinematographic.
The solo section is not very interesting in its own but when layered with the strings it adds a very nice lead touch.
The instrument features 3x seperate outputs in top of the general output, and jack input for piano/harpsichord sustain pedal and a volume pedal.
There were 2 revisions made to this instrument, and the only difference is the power supply. The most common you will find is this one and it uses an external power supply (18v DC but you can use anything between 15 and 24 since this supply gets regulated inside the synth). The second one has a built in 230v power supply and you can easily recognized it because it has a red translucent on/off switch.
The builtin power supply probably lowers the tendency to hum and magnetic interference you get with the first one, which can be quite picky on the power adapter you use. But I never had a second version at hand to compare to the first one so i can't be sure.

This is the 5th String Performer I serviced and though they had all different issues one common issue it that they ALL had cracks on one or more PCB, leadind in cut traces.
The design of the instrument is clever but not sturdy enough. The case is very well built and solid and it's very hard to seriously damage it.
But all the 12 oscillators and filter PCBs are socketed to the motherboard which is underneath the keys, and are screwed to a hinge that tends to get bent when the instrument is subject to violent transport, so the pcbs bend too and crack.
This result usually in some mute notes on all poly section (just like if a divider has died) or on some section only, and very often the solo is also dead because of a cracked pcb.
This is one of the synth I would advice not to have shipped, the chances to receive a 100% working instrument is closed to null."

Monday, November 21, 2022

Hillwood SY-1800 Analog Synth

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

You can find another demo previously posted here.

via this auction

"This is probably the rarest and strangest bird I've met. You may think it's a kind of simple monophonic analog 1 oscillator synth like the Roland SH 2000, but there is more than meets the eye. It took me some time to understand what's going on and to this day I am still not sure exactly how it works but it looks like the oscillator is a kind of very early FM based oscillator. Check the video, especially the "bell" presets and you'll know what I mean.

Tone is shaped by 3 faders labelled "Fundamental", "Overtone" and "Brillance", and these are interconnected.
There is a simple envelope which works as attack decay (labelled "attack" and "sustain") by default but can be switched to attack release by the push of a button ("sustain long"). Funny thing is the attack fader is inverted compared to classic synth topology: when raising the fader the attack gets shorter.
All the presets have their own envelope setting and depending on the presets the attack and decay faders do not behave exactly the same, ie the envelope faders do not totally overide the presets envelope.
You can also have the envelope assigned to the filter by switching on "VCF expand", and control the envelope to VCF amount with the "Expand" fader.
The "Expand Envelope" seems to invert the VCF envelope. It's quite efficient on some presets and not on others.
"Touch portamento" switch is actually a key retrigger option. When activated envelope retriggers on every key stroke (low note priority) otherwise the envelope is legato. So it has nothing to do with the "portamento" fader which is indeed a portamento effect. "Gride" is basically a pitch bend (upwards only).
"Growl" switch adds... growl: it adds a kind of brassy attack to the sound. Not efficient on every preset but can add to the realism of the sound on others.
There is also a LFO which can be delayed (it's more like a slow attack then a proper delay), consisting of either pulse or triangle wave shape, that can be assign to "vibrato", "wow", "chorus", "tremolo", and you can have the envelope repeat on the lfo speed thanx to the "repeat" switch.
And finally there is a noise generator with dedicated fader level and a "Noise only" switch that is self-explanatory.
This makes for a uncommon and interesting monophonic synthesizer. Very expressive in my opinion, once you managed to tame it.

I did service this one as much as I could but without any information and service manual it's hard to be sure it's sounding as it should. There are like 15 trimpots inside to calibrate the synth and you definitely can hear most are changing tone and harmonics.
Anyway it seems to fully function, it's scaled and tuned and it sounds great but again I can not be 100% sure it's sounding as it was intended.

Cosmetic wise the synth is in good condition, especially considering the rather cheap build quality. But of course it has some scuffs here and there."

Friday, June 07, 2024

Rare birds: Vermona Phaser 80

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

"Quick demo of the vintage DDR phaser unit by Vermona, based on classic TCA350 Bucket Brigade Device."

Phaser is for sale here.

and Roland Juno 106 Kiwi upgraded here. [pics previously captured here]

Pics of the Phaser for the archives:

via this listing

"This is a rare DDR analog phaser based on the classic TCA350Y Bucket Brigade Device. The unit is in fully working order and in good cosmetic condition. Original DIN sockets were replaced by more convenient jack ones."

Monday, May 22, 2023

Jen SM 2007 italian string machine 1979

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

Update: now listed on Reverb.

"Here is a demo of a quite rare Jen SM 2007 string machine. Unit was fully serviced and is for sale. Get in touch if interested.

The SM 2007 is a very nice stringer for whomever like these classic sounds. Very compact and lightweight and still gifted with quite a number of features.
There are 3 strings sounds (cello, viola and violin) that can be individually mixed, variable attack and sustain, a tone control and of course a triple BBD chorus.
The later has 3 presets: ensemble, solo and organ that are basically different setting of the chorus effect, 'ensemble' being the full triple chorus, 'solo' uses only 2 of the choruses for a less dense sound and "organ" is the dry sound of the string sounds, thus enabling to use external fx with more flexibility.
"Auto sustain" switch makes it possible for sustain notes either to be cut when new ones are played or be left to release. And the sustain length can be massive !
Soundwise it is silky and lush, the closest I can think of is the Logan/Hohner string melody. A bit like Elka rhapsody too but denser since it has triple chorus, not a double one.

Recorded dry with no treatment."

And some pics. Note the stand is not original. Perfect fit though.

Saturday, December 02, 2023

rare birds: Elka Drummer One

video upload by ohm_studi_ohm

"Quick demo of an Elka Drummer One I just serviced. Every single electrolytic capacitors were replaced. You really HAVE to do it on those units, otherwise it doesn't sound like it should, and deserve. There is no way the bad quality capacitors italian manufacturers used in the 60s and 70s could still be in shape 50 years after. And it impacts the sound a lot in those analog drum machine, especially the attack and decay of the sounds.
Apart from that and trimmers that need attention it is a quite well built unit and easy to service.
I tuned the sound with quite long decay, I like when the sound, especially toms and congas, are bouncy. You could of course make them tighter if you like.
It's a pity the unit doesn't have more patterns that use the Cowbell and Conga sound. There is only one pattern using them each.
It is however easy to add MIDI or trigger input should you want to play the sounds as a regular drum expander.

Please note there is a slight distortion at some point in the video, it doesn't come from the Elka but from the Teisco Vocal 120 mixer it is plugged in, which has some very dirty gain attenuator switches i never manage to really clean, so eventually i'll replace them. Anyway, here is the Elka Drummer One.
Listen with headphones or decent speakers !"

Tuesday, February 07, 2023

Roland DC-50 analog BBD chorus / delay + Roland Juno 106

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

"Unit is for sale here.

Here is a demo of the Roland DC-50 with a Juno 106.
I use a footswitch to turn the effect on/off and also compare it to the built in Juno chorus to give you an idea how they differ.
Main difference is the DC-50 is mono of course, but it can do echo. Also chorus effect is much more pronouced than the Juno one and depth can be adjusted.
Recorded straight with no treatment nor eq."

via this auction

Tuesday, June 06, 2023

DIY Farfisa analog triple chorus / ensemble FX

video upload by ohm_studi_ohm

"Quick demo of a custom made ensemble FX box based on a Farfisa analog Bucket Brigade Device triple chorus. Basically it's the ensemble fxfrom the Farfisa Synthorchestra 4.
Introduced by Eminent in their Solina String Ensemble, the triple chorus is what makes in most part for that luscious string machine sound typical of the 70s, and these fx have been built in all the major string synthesizers, from the italian ones (Crumar, Logan, Elka etc) to the Japanese ones (Roland RS 505, Korg Poly Ensemble etc), and to the american ones (Arp Omnis, Moog Opus 3 etc) with minor differences in design.
As you can hear you can turn any synth sound in a gorgeous string sound.

I built unit like these from time to time so if you’re interested in buying one get in touch."

Monday, June 19, 2023

Custom Made Wersi Wersivoice Ensemble FX on Roland Juno 106

video upload by ohm_studi_ohm

"Very quick demo of a custom built Wersi Wersivoice analog triple chorus i'm selling just to showcase once again how lush these boxes sound and how they transform any synth in a great string synth.
I adressed the Wersivoice and it's cousin the Böhm Phasing Rotor in more lengthy and detailed videos [posted here] if you're curious about these units."


Switched On Make Synthesizer Evolution Vintage Synthesizers Creating Sound Fundlementals of Synthesizer Programming Kraftwerk

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