Arp Omni 2 with external ensemble FX (Wersivoice)

video upload by ohm_studi_ohm

"if you've watched some of my videos you know I love string synth and string ensemble FX, I collect the former and build the latter.
I wanted to test how an Arp Omni would sound through a Wersivoice unit.
To do so I used the synth section of the Omni and plugged it to the Wersivoice, since the waveshape of the synth and string section of the Omni are basically the same.
In the first part I A/B the 2 chorus sounds by using a foot switch. It's quite obvious which is what so you'll figure out. As you'll probalbly find out the Omni built-in chorus sounds mellower than the Wersi, which is brighter and harsher. Not better or worse, just a different taste. It's worthy to note the Omni 2 chorus is build around Reticon SAD512 BBD chipsets (so is the Moog Opus 3 btw) and this Wersivoice is build around Panasonic MN3004 (the same used in Roland Jupiter 4 / VP330). Early Wersivoice units (FM76s and WV3 / WV7 pcb) are build around philips TDA1022 and sound mellower. I'll make a demo with the Arp and one of those at some point.

Then in the second part this is when it gets really interesting... Since we use the synth section of the Omni we have access to a full ADSR enveloppe and a resonant filter with control over it by enveloppe, LFO and external pedal.
And this allow for a much wider sound palette.
Thanks to the enveloppe shaping the VCA you can get some string articulations that are not possible in the string section since it has a ASR enveloppe (meaning you can control Attack and Release but there is no Decay and Sustain is always maxed). Great for swell, staccatos, stabs etc
It's also worth mentionning that the release of the ADST (synth) enveloppe is tied to the string section release, this one being the "master" or final release. If you want a long release on the ADSR you have to bring the String release up. This is not an issue, it is the way it is designed and that's one of the drawback of paraphonic design.
And then comes the resonant filter... with it you can shape the tone of the sound to almost choiry / vocaly ones. And you can bring this more lively by using the LFO or an external pedal to open the filter like I did at some point.
And of course you can always run the string section through the Wersivoice, which I did in the last part. And that, when the builtin Omni's chorus is set to phaser mode gives a very thick (sick ?) sound.
Hope you like the video.

00:00 builtin chorus / Wersivoice comparision
02:48 quick discovery of ADSR and filter
05:19 example of ADSR use for string articulation
08:19 example of Filter use for tone shaping
10:56 use of external swell pedal (not on screen) to control filter and then LFO
14:41 BONUS string section in phaser mode through Wersivoice"

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."

rare birds: Welson Ritmo / analog drum and accompaniment unit

video upload by ohm_studi_ohm

Also see this one from 2022 with a smaller keyboard controller.

"The Welson Ritmo was a accompaniment unit intended as an add-on to some of Welson's organ line. It consists of a rhythm unit, a bass section, a chord section and an arpeggiato section. All sounds are of course fully analog. It is very similar in features and sound to the Elka Wilgamat, Böhm Böhmat and Wersi Wersimatic CX1. They are actually built around the same chipset family (SGS M2xx), but the Ritmo cannot be programmed.

It was never intended as a standalone unit so I built a custom keyboard to make it so.

Unit is very easy and straightforward to use with some nice features: for instance you can play it in "free chord" or 'one finger chord'. In the first mode you need to make a 3 notes chord to trigger the arp sound. With one or 2 notes you only trigger the bass and chord sounds, this make for some nice performance variations. The bass section can be set to 'walking bass', and in this mode you also need 3 notes to trigger the melody.

In 'one finger chord' you play a major chord with one key. There is a pedal input on the back to make the chords minors. I also added a switch on the keyboard to alternate between major and minor chords when playing in the "one finger chord" mode.

Other nice features are "keystart" (obvious functionnality) and 'memory' which holds the played notes (and rhythm). And like almost all the preset rhythm units you can combine different rhythms together."

Pics via SALES.OHMSTUDIOHM@GMX.FR

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rare birds: Technics SY-1010 analog mono synth

video upload by ohm_studi_ohm

"Demo of a recently serviced (and converted to 230v) Technics SY-1010 analog mono synth.
Only produced for the japanese market you don't find many out of there.
Very simple design but very nice sounding, a bit like Roland SH-101.
The VCA initial gain control, continuous oscillator pitch adjustement and fast LFO give this little synth a lot more possibilities that you would first think of.
Extremely compact and lightweight too.

Get in touch if interested: sales.ohmstudiohm@gmx.fr"

Wersi Wersimatic CX1 / CX2

video upload by ohm_studi_ohm

"Demo of a Wersi CX1 I just serviced. Showcasing the general functionality of the instrument by fiddling with some presets I made.

This unit is actually more a CX2 since it was upgraded at some point to a CX2. This was a possibility given by Wersi when they released the CX2 not too long after the CX1. Basically it replaced the full analog drum sounds with 12 bit PCM drum samples. Otherwise the CX1 and CX2 shared the same analog arranger and programming unit. There are still 4 analog drum synthesized sounds in the CX (maracas, claves, tambourine and "synthdrum", the latter being only manually triggered).

The CXs also have 3 SSM2044 filters for the 3 analog parts (bass, chord and arpeggio) and it features a great Wersivoice BBD triple chorus card to give that ensemble sound to the string presets sounds (check my videos about these units if you dont know how they sound).

Both drum and arranger parts are programmable and you can store your own 16 presets, in top of the 48 builtin presets. Instant 80s and italo disco sound with this unit. Very close in philosphy and sound to the mlighty Bohm Digital Drums, with the latter being a much more advanced unit though."

Programming Crumar BIT99 with MIDI Controller

video upload by ohm_studi_ohm

"This synth is for sale. You can buy it directly (sales.ohmstudiohm@gmx.fr) for 1450 euros or buy it on eBay (https://www.ebay.com/itm/305202255093) or Reverb https://reverb.com/item/74807341) [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."

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.
STAND IS NOT INCLUDED.

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."

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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."

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Crumar Bit 01 demo with midi controller

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

"Here is a demo of this italian 6 voice analog polysynth i'm selling (via this auction)
Unit was upgraded with the great Tauntek firmware and can now be controlled remotely over midi by Control Change with any controller.
In the demo I basically flip through the unit presets and edit some of them on the fly just to show how easy it is now to program this otherwise austere synth.

I didn't demo the bi-timbral feature of the rack. You can have 2 different presets, lower and upper, either layered ("double") or split. Lower and Upper parts can have their own audio output.
Preset from 76 to 99 are allocated for the performance presets and need to be dialed in (you can't use the + and - value switch to select those like I did on the video)."

SN 00522 via this auction

"Italian 6 voice analog polysynth. This is the CEM 3328 version, not the SSM 2044 one, in the rare white colour.

This unit was serviced and upgraded and is in perfect working condition, see video.
What was done:
- power supply capacitors were replaced
- new battery was installed
- Tauntek new firmware eproms were installed. You can now control the unit directly over MIDI with CC with any hardware or software controller
- Midi thru socket was modified so that you can export your preset by sysex dump over midi (original could only export presets through the "tape" function)

It also comes with some goodies (well especially for french speaking person)
- original owner's manual + preset lists (in french)
- original schematics diagram
- original Crumar Bit range advertissement (in french)
- original inspection card from factory (this unit came out from factory in November 1985)

Condition is very good with only minor scuffs to the nice white metal paint."

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Custom made Farfisa analog drum machine with Korg Stage Echo SE-300

video upload by ohm_studi_ohm

"DRUM MACHINE FOR SALE HERE: https://reverb.com/item/71915584

This is a scavenged rhythm unit from a 70s Farfisa spinet organ. Sounds are of course 100% analog on this one, no IC only transistors and diodes.
10 rhythms that can be combined and only volume and tempo control.
Sounds nice with the tape delay and spring reverb unit Korg Stage Echo."

Pics captured here.

Custom Made Wersi Wersivoice triple analog chorus / string ensemble effect

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

Update: "THIS IS A NEW VIDEO. THE CHORUS WAS NOT PROPERLY ADJUSTED IN THE PREVIOUS ONE."

"A VENDRE / FOR SALE HERE

This Wersivoice unit is based on later revision model that uses 3x Panasonic MN3004 Bucket Brigade Device chipsets, the same chipsets used on Roland VP330 or Jupiter 4 chorus for instance, instead of the more classic Philips TDA1022 you find in earlier Wersivoice units.

No fuzz in this unit, it only does the string ensemble effect. Mono input / mono output. 3 positions switch with true bypass and mute position. Unit has a built in power supply that runs on 230v.
Case is DIY so don't expect manufacture quality.
Works perfectly of course.

recorded dry with no further treatment."

via this auction

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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)."

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."

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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."

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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.

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Vermona ET-3 combo organ + Dynacord Echocord Super 75 tape delay

video upload by ohm_studi_ohm

"Quick demo of a nice organ / delay in the form of a Vermona ET3 and Dynacord Echocord Super 75.
You can get quite a large variety of sounds with this combo, for 60s pop to experimental droning."

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:

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Jen Synthetone SX-2000

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

"FOR SALE HERE

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."

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Rare Elex Excelsior EK4 Strings & Brass Synth SN 6937

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

This appears to be the first post to feature one. You can find additional string machines by Elex in previous posts here.

via this auction

"Extremely rare italian string machine, built by Elex (ELettronica EXcelsior), also sold by Hohner at some point. Very close in sound to the Crumar Performer or Elka Rhapsody.

It offers Strings and Brass section, with independent volume for each instruments, a very nice filter in the brass section, as well as vibrato, and the string section has long crescendo and sustain settings.

Unit was serviced and is in very good working order except for the attack in the Brass section that doesn't work. This synth use a very rare SSM2050 chipset as the enveloppe generator on the brass section. This is the same chip used in the Sequential Circuits Prophet 5 and the RSF Kobol for instance. It simply can't be found anywhere. But if you are lucky to own one you can most probably fix the attack on the brass section ;-) Apart from that everything is working. Capacitor in the power supply were replaced and synth was calibrated. It uses the typical "ensemble" effect based on a triple BBD chorus, with the same TCA350 chipsets you have in the Eminent Solina, Crumar Performer, Logan String Melody and so many more classic string synths.

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."

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SIEL Orchestra for sale / a vendre (ARP Quartet)

video upload by ohm_studi_ohm

"Quick video of a SIEL Orchestra I just serviced, in order to demonstrate the differents sounds you can get out of this instrument.
Also sold as the ARP Quartet this keyboard offers 4 parts: Brass / Strings / Reed / Piano
Nice filter on the brass part and strings sounds are not too bad either. They do use the same TCA350 BBD chipsets as other classic string machines like the Eminent Solina, Logan String Melody or Crumar Performer.
I use a sustain, pedal as some point, mainly on the piano part.
Recorded dry and no treatment."