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

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."

Monday, November 20, 2023

Seuential Circuits TOM with Tauntek TOM16 extansion

video upload by ohm_studi_ohm

"The Sequential TOM was already a great drum machine at the time it was released, with a lot of nice features, especially regarding MIDI implementation. You could play, record, synchronise the machine over MIDI and adjust sample direction, volume, pitch and pan of every sample either on the device or over MIDI, in real time and for every step ! That gives you lots of possible variations. Not many drum machines could could achive that at the time.

And now thanx to another amazing engineering by Tauntek you can have 16 kits in the instrument at all time, without the need to switch cartridges. And even more important: you can swap the internal kit samples as well as the cartridge ones, enabling for any combination of 2 kits you wish. This is impossible with cartridges or other upgrade available, and only possible thanx to Tauntek firmware. And that makes a huge difference. Note that you can only have 15 sounds at hand not 16. The 8th pad from the cartridge layer is always a trigger out message and won't trigger a sound, even if the loade kit has 8 sounds.

You can even make your own kits if you have access to an Eprom programmer.
Check Tauntek dedicated page for more info (
This unit also had its RAM maxed out, expanding the internal 8k to 32k and thus bringing the stock 2,300 notes capacity to a whopping 10,400. And believe me you run very quickly out of memory if you make some complex patterns with different variations.

So here is the demo, i didn't make patterns demos for each of the 16 kits but you'll get the idea, and I didn't go too deep into external MIDI playing/programming but bare in mind you can record instrument tuning pitch, volume, pan and sample direction (reverse) for every instrument on every step.

Here is the timeline:
00:00 stock kit patterns
02:28 TR808 kit patterns
03:56 TR909 kit patterns
05:08 TR606 kit patterns
06:25 CR78 kit patterns
07:17 sound preview of all the kits included in the box
11:18 quick realtime patterns programming using external pads

list of the kits included in the TOM16:
SCI Internal
SCI Basic Percussion
SCI Contemporary
SCI Latin Percussion
SCI Special Effects
Drumware Rock Drums
Drumware Techno Drums
Drumware Orchestral
Drumware Percussion 3
Drumware Hippefex
Drumware Analog Drums
Roland TR808
Roland TR909
Roland CR78A
Roland CR78B
Roland TR606"

Friday, November 17, 2023

Rare birds: Elka Wilgamat 1 / analog drum machine and accompaniment unit

video upload by ohm_studi_ohm

"Here is another "one man band" from the 70s I just serviced. Many dead CMOS chipsets, lots of bad connections on the motherboard daughterboards sockets (broken pins, bad solder joint) and a dying voltage regulator, among other things. Custom built keyboard to trigger the accompaniment unit, with jack socket input for pedal that introduce drum breaks. A different flavor than the Welson Ritmo I recently demoed but definitely in the same mood.
Recorded through a Teisco 120 to add some reverb."

This appears to be the first post to feature the Elka Wilgamat 1. Note the "1" on the right. The Elka Wilgamat minus the "1" has been featured on the site before in previous posts here. Which came first? :) You can find additional Elka Wilgamat models here.

Update: according to Ohm Studio: "Electronics are exactly the same. I think this one is later and was an add for some Elka organ, maybe Concorde or something. The black color is I think factory since it’s all over the case even inside. It’s clearly the same fake wood as the original but painted black, probably to better match the organ aesthetics. I definitely remember seeing auctions with Elka organ and this wilgamat unit bundle. Also the complete wilgamat electronics and controls are fitted in some Elka organ, spinet and combo. Don’t remember which model but I did scavenged à spinet one to retrieve all the pcbs."

Wednesday, November 15, 2023

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"

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."

Tuesday, November 07, 2023

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."


Thursday, November 02, 2023

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:"

Saturday, October 21, 2023

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 ( 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."

Friday, August 25, 2023

Crumar Bit99 + Wersi Wersivoice

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."

Korg Mini Pops 3 & Korg Mini Pops 7

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."

Tuesday, August 08, 2023

Crumar Bit 01 demo with midi controller

video upload by ohm_studi_ohm

"Here is a demo of this italian 6 voice analog polysynth i'm selling (
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."

Saturday, August 05, 2023

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

video upload by ohm_studi_ohm


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.

Tuesday, July 25, 2023

Custom Made Wersi Wersivoice triple analog chorus / string ensemble effect

video upload by ohm_studi_ohm



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

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)."

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."

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, May 22, 2023

Jen SM 2007 italian string machine 1979

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.

Wednesday, May 03, 2023

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."

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:


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

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