Blue Mondayish ELKA OMB5 with Custom Drum Kit

video upload by ohm_studi_ohm

"I just finished servicing an Elka OMB5 and building a custom drum kit for it so I had some fun with it.
All sounds are from the OMB5, no fx used."

ELKA OMB 5 with custom drum kit

video upload by ohm_studi_ohm

"herre is a demo of an Elka One Man Band with custom drum sounds.

The OMB5 is a nice 4 part arranger with rhythm channel, bass channel and 2 accompaniment tracks. Sounds are FM (from the elka ER/EK/EM 44) and the drums are PCM sampled from the Drumstar 80. It has MIDI in and out so you can either control and play the different part from the keyboard or from MIDI, it syncs and transmits clock as well as single input notes or sequenced notes. I like using it with external midi controller so I can play the 3 different melodic part separately (when playing from the keyboard notes always trigger the 3 part together).

Though the drum samples are actually quite good if you like 80s sounds (especialy percussion and cymbal sounds), I decided to replace some of them with some I favor more, using sounds from LinnDrum, Oberheim DX, Roland TR808, CR8000 and TR707. I also adjusted level by using compression on some other stock sounds.

The audio format used in the OMB5 (and the Drumstar 80 which drum part is derived) is the same as in those classic 80s PCM drum machines, ie 8 bit µ-Law unsigned sample. Sample rate is 25000 hz (or so) in that one.

Replacing sound is not as straightforward as in those drum machines because instead of using 1x eprom per sound there are several samples per eprom (7x 256 kbyte eproms are used in the OMB5 to accomode for 32 sounds) so you need to edit the audio file and replace the existing sample with your own but it needs to start at the exact same adress as the original one and it should have the same length or be shorter.

So basically what you do is:
read the eprom bin
convert to uncompressed audio
edit that file and edit/replace the sound you want making sure you dont change file size nor start adress of the sound
convert the uncompressed audio to µ-law 8 bit
burn the new bin file

if you're interested in getting those sound I can sell you a full 7x eproms kit ready to use. I can be fitted in the DrumStar 80 too.

here is a list of the 32 sounds, with original and replacement when there is:

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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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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 Performer MK2 (SSM 2040 filter) / analog polyphonic synth

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

"The Crumar Performer is a string and brass synth that has some features that grants it to be part of the hall of fame of paraphonic analog synths.
First it's a quite compact and lightweight contender in such a category.
Then it has a very nice and warm sounding resonant filter, based on the SSM 2040 and 2050 chipsets, just like in the Sequential Prophet 5. First version of the Performer used a Moog inspired transistor ladder filter, also resonant. It sounds good too but I definitely prefer that one.

The string sound have variable attack and release time and those can be quite long, great for pads and ambiance. But in my opinion what makes it special is the 3 band Eq which allows for quite a large panel of variety of tones, and it can get into almost vocal territories (check video at 05:49).
recorded through a Dynacord VRS23 for added reverb."

via this Reverb listing

"the Crumar Performer is one of the classic string synth. This one is the second version with the updated filter (SSM 2040 like on the Sequential Circuits Prophet 5).

Unit was serviced and is perfectly working. Power suply was recapped and everything was cleaned and calibrated. Cosmetic is quite good, despite some scuff and wear here and there.
It's quite compact and lightweight compared to others string synth (77x35x19cm 12kilos)"

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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."

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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)."

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."

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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Akai AX80 with realtime MIDI controller

video upload by ohm_studi_ohm

"Demo of the Akai AX80 8 voices analog synth with Tauntek upgraded firmware that allows among other improvements MIDI Control Change editing of all the synth parameters.
Just tweaking a bit on a bass preset and a pad preset, and further demoing a few patches I made. No FX were used."

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"

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: Farfisa Rhythm Maker 16

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

via this listing, also on Reverb

"rare analog drum machine from the 60s.

Basically it's almost 100% the same circuit as the Ace Tone FR1 / FR2L and as the Farfisa Melodic Rhythmer CER-60 in a different case.

Was also sold / rebranded by other manufacturers like NDK, Nomad or Goya, often in slightly different cases and different names but sharing the same pattern and cancel switches.

Unit was serviced: every electrolytic capacitors were replaced and unit was calibrated. Sounds and works as it should.
Cosmetic is in quite good condition except sor some minor scuff and wear."

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rare birds: Rolling REC-4 analog BBD delay & spring reverb with no so rare Elka Solist 505

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

"The Rolling REC-4 is rebadged Evans Echopet EP-250, exact same PCB (labeled EP-250 by the way). It's a very nice spring reverb and BBD delay combo. It uses 3x Panasonic MN3005 chipsets, the same used on more famous BBD delay like the Yamaha E1005 / E1010 and Ibanez AD202 among many others. What's make it quite unique is that the delay sound goes to the reverb tank so you can get some very dense effect. If you want only the spring reverb sound you need to leave the "repeat" control of the delay fully counter clockwise.

The Elka Solist 505 is a simple italian monophonic analog synth with preset and some limited sound editing control, like a simple attack release enveloppe that can be routed to VCF or VCA, a 'wow' effect, which is more or less a resonance control; cutoff control, vibrato depth (speed is fixed) and 'bend'.
It is however very nice sounding because of the Moog inspired transistor ladder filter."

via this listing

"The Elka Solist 505 is a simple italian monophonic analog synth with preset and some limited sound editing control, like a simple attack release enveloppe that can be routed to VCF or VCA, a 'wow' effect, which is more or less a resonance control; cutoff control, vibrato depth (speed is fixed) and "bend". It is however very nice sounding because of the Moog inspired transistor ladder filter.

Unit is in fully working condition, see demo.
Cosmetic is not so great, mainly the front panel paint and lettering."

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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."

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Farfisa Syntorchestra demo and tech tips

video upload by ohm_studi_ohm

"i've serviced several Syntorchestra and I found out that because of the age, build quality and design limitation of the synth, owners can sometimes wonder if their unit is working and sounding how it should.
So here you have an example of a properly working unit, with its strength and weakness. These instrument are quite unique. Before I laid my hands on one I was not really convinced by the demos I heard. Sure is sounded nice but nothing to rave about. But I must admit that when you have the chance to play with one you get quite quickly drowned in its sound. There is something very unique about that instrument, nothing I can really compare it too. Especially when you play both sections together, something magical happens.
First part of the video is a quick performance using a Welson S12 drum machine and Vermona VRS23 for reverb. Second part is recorded dry from the synth with no production. I go over every sound and parameter of the synth in that section so you can compare to your unit.

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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

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Simmons SDS7 Digital Analog Drum System (1983) / hybrid analog drum synthesizer & 8 bit PCM rompler

video upload by ohm_studi_ohm

"in the first part of the video I run a simple pattern on a Roland TR8s that triggers the SDS7, and I demo a few kits I programmed.

On the second part I play live drums over a simple kick / hat / clap pattern and review the same drum kits and finally I play the sounds alone.

I'm no drummer so forgive my playing. These last parts are mainly intended as to demo how the SDS7 handles dynamics.

recorded through a Tapco 4400A reverb. No other fx or editing.

The Simmons SDS7 combines analog drum synthetis and 8 bits sample playing.
Each voice lets you blend 1x VCO (CEM3340), 1x 8 bit sample on eprom (like many 80s drum machines ie LinnDrum, Oberheim DMX, Sequential Circuits DrumTraks etc), 1x noise generator and 1x click generator.
Then those 4 sources pass through a nice 24db resonant filter (CEM3372), which doubles as VCA. There is a simple cutoff enveloppe and vca release parameter, and both the VCO and sample have a simple pitch enveloppe as long as a lfo to pitch modulation depth. The lfo speed can go to audio range thus enabling FM tone, great for bells and fx.
All voices card pcbs are the same except for the eprom containing the sample and this can be replaced with other sound (the clap on this unit is a CR8000 clap i programmed for instance).
There is however a second type of card, hi hats card, that differs from the basic one with some more components that let the voice be controlled by the hi hat pedal (decay of the sound mainly). It's easy to modify a regular card to a hi hat card, and to build a simple adapter in order to use a momentary switch pedal to act as the hi hat pedal. You can even use a progressive pedal to mimic the opening of the pedal, this is what I'm using and doing on the video (off screen). Info on how to achieve this are available on this site (thanks to the author for sharing this ): https://www.drummachines.de/beatboxer... If you're interested in these units tons of info are available on that site (again thanks to the author for the great job): https://snw.lonningdal.no/sds7.php"

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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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.

TECH TIPS:
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."