An edited version of this text also appears in
SOUND ON SOUND magazine Vol.12 No.12. OCTOBER 1997

Review by Chris Carter


Sporadic sightings of MIDI to CV converters have occurred since MIDI keyboards first appeared in the eighties, with at least half a dozen models that I can think of without much effort. Some have been more successful than others, early units were as temperamental and unreliable as the gear they were supposed to be controlling. However with the advent of cheaper and more accurate D-A converters it's now possible to build very stable, reliable and feature laden units. At the moment Kenton is probably top dog in this specialised area but E.E.S, who aren't exactly novices when it comes to designing and building for the electro-music industry either, with a creditable pedigree building interfaces for C.Lab, are hoping to muscle in with this new feature bursting MIDI-CV7 interface.

Each of the seven MIDI-CV7 channels work independently and each has an extensive range of programmable parameters. The system is menu driven, using a nice, clear 2x20 digit, backlit LCD and in its factory fresh state arrives out of the box with 30 identical pre-sets in its user-programmable memory locations. Four arrow keys allow navigation through the system pages and two buttons and a data knob enter and change parameter values. There are also nine (extremely bright) LED's to indicate CV/GATE, MIDI in and MIDI clock activity. It was a nice surprise to find an internal power supply, particularly considering the size of the case, because although this is a rack mounting unit it has to be one of the smallest I've come across, being only 1 rack unit high and 12 cm deep, (not including the somewhat superfluous, front mounted grab handles). The crowded rear panel has fourteen 1/4 " jack sockets for the seven CV and GATE output channels, plus the usual MIDI in/out/thru sockets, a DIN Sync output socket and an IEC mains connector.

The erasable factory pre-sets are configured as seven CV/GATE channels assigned to corresponding MIDI channels 1 to 7 with each individual CV output programmed to transmit a control voltage containing NOTE, PITCH BEND and LFO information, while each GATE output is set to transmit a positive 5V trigger. The CV outputs are set to Octave/Volt scaling, which is fine for most users, but this can be changed channel by channel if needed to Hertz/Volts for Korg and Yamaha systems. Using one of these pre-sets it is possible to use the MIDI-CV7 straight out of the box, assuming your gear is compatible that is. However to get the best out of MIDI-CV7 the first thing you need to do is to calibrate the interface to your analogue synths using a very straightforward process in the CV/ADJUST pages.

Using a MIDI sound source and MIDI keyboard you first play the bottom note on your keyboard and use the MIDI-CV7 data knob to adjust the lower tuning of your analogue synth or VCO , you then play a MIDI note at least 2 octaves higher and tune the upper range, the display then reads 'OK' and that's it, piece of cake!

The CV tuning range is very wide, 1.5 octaves at either end of the scale, and allows plenty of scope for taming troublesome VCOs. Things can get a little laborious if you need to tune all seven channels for seven different synths but at least you do have this option available, and is particularly useful if you have a large collection of analogue synths or VCOs. There is also the added bonus that any special patches or set-ups can be named and saved as a User Preset into one of the 30 memory locations.

There are a number of output options available for each CV and GATE channel (see box). For regular use, most channels will be set to NOTE+PITCH+MOD, this gives you a control voltage mix of keyboard note, pitch bend and LFO modulation. The pitch bend range and LFO depth can be programmed from go from zero to ± 1 octave in semitone steps and the LFO modulation can be introduced by MIDI mod wheel or channel pressure. The GATE/TRIGGER signal can also be programmed to transmit 5V, 9V and 13V low to high (standard) or high to low (S-Type) triggers, which along with the Hertz/Volt option means you can drive almost any type of synth.

The amount of programmable parameters available for each CV/GATE channel add to the versatility of the unit immensely. Any CV/GATE channel can be assigned to any MIDI channel, including the option to assign multiple CV/GATES to a single MIDI channel and the benefits of this method become apparent if, for instance, you want to send separate LFO or velocity control voltages through additional CV channels to a VCF, VCA or to modulate a VCO pulse width. The only drawback here is that if a CV channel is programmed to transmit anything other than keyboard note information then the associated GATE output is disabled. This is a shame because, as anyone seriously into analogue synths or modular systems will tell you, separately programmable gate signals can be put to all sorts of good uses, such as triggering analogue sequencers, arpeggios, ADSRs, sample and hold generators and even triggering noise gates and effects units. Hopefully this omission can be addressed with a future software update.

There are fundamentally two ways the MIDI-CV7 handles note information, Mono and Poly. In Mono each CV/GATE channel looks for any note activity on its assigned MIDI channel. There are Mono Priority playing options for highest note, highest note follow, lowest note, lowest note follow, newest note and newest note follow. Most of these are self explanatory, however the Follow feature is used when chords are played in Mono mode. As you release held notes the next valid note of the chord will be transmitted. This happens independently of all other channels, unless more than one CV/GATE has been assigned to a specific MIDI channel, in which case you can use Poly. With Poly Priority On, any playing note will be active until released, even if a new note is played. Or there is Poly Priority New which replaces the oldest note in priority to any new notes played. Of course the number of notes playable depends on the number of CV/GATE channels assigned to the current MIDI channel but remember you can have up to 7 note polyphony if you have enough VCOs, also additional MIDI-CV7s can be cascaded for greater polyphony.

Having extra LFOs at your disposal opens up all sorts of creative avenues with analogue synths and half the fun of using such gear is thinking up more and more devious and mind boggling patches. If you have multiple CV inputs on your VCOs, VCFs, VCAs, VCADSRs and even VC effects then the modulation possibilities are almost infinite. To find 7 programmable LFOs in anything, let alone a MIDI/CV interface, is rare but that's what's on offer here, one for each channel and while they may not be as well specified as types found in most synths they're pretty good nevertheless. Each LFO can produce three basic waveforms, SINE, TRIANGLE and PULSE and each waveform has a variable duty cycle and negative, positive and symmetrical waves available. In addition, the speed and waveform cycle of each LFO can be set internally, or synced to an incoming MIDI clock and the duty cycle can be modulated by a selectable MIDI controller. The depth of LFO modulation appearing at the CV outputs can be programmed to a pre-set level or introduced using a MIDI controller such as a mod wheel or after touch. I would like to have seen a ramp waveform and possibly a sample & hold or random setting but these features will probably be available on the analogue gear you are using. It's quite possible (and pretty easy) to put this interface to use as a multiple LFO generator with a different LFO and waveform on each and every channel, I love it!

As mentioned earlier there are almost seven of everything and this includes the Portamento and Glissando options. The Portamento is pretty standard with adjustable settings for Time and Slope, plus various playing modes: Legato, Continue and Update. But what I found more interesting was the Glissando option. If you haven't come across this feature before then it could be described as a basic type of arpeggiator. As with Portamento the notes flow across the keys depending on which are held down, however the flow of notes with Glissando occurs in semitone steps. When Time Mode is on the time taken from one note to the next is variable ( in ms steps ) from a plod, plod, plod through to a fast trill. It would be nice if the Glissando speed could be synced to MIDI but still, this is a welcome and unexpected feature. I had great fun setting different channels to different Glissando speeds for some really complex, syncopated sequences, all in real time too. Great stuff!

Default mode for the 5 pin DIN Sync output is a standard +5V, Sync 24 signal, suitable for driving pre MIDI, Roland drum machines, BassLines and such like. The are options to change the sync trigger from a 'leading' to a 'trailing' edge and to enable a Clock Continue signal. There is also a MIDI Clock Divider parameter which controls the output resolution of the DIN Sync clock with an adjustable range of 1-128, where 1 is the default value and 2 halves the speed and so on and so on. At its fastest setting of 1 the display also reads '96 Notes', which I assumed meant 96 ppqn, however it probably refers to the MIDI resolution as I couldn't get the Sync clock to produce an output faster than 24 ppqn. This is a shame, as Korg drum machines require a 48 ppqn clock and I'm pretty sure some American drum machines used 96 ppqn. Two LED's on the front panel also indicate DIN Sync Start/Stop and Clock activity and could be useful tools for trouble shooting lost clock signals and dodgy leads.

My only real disappointment with the MIDI-CV7 is the way in which it handles User Presets (a slight misnomer, as by nature they are not really pre-sets at all). On the review model only one pre-set was immediately available for use and to access any others, they first had be loaded from memory, one at a time, into what is in effect an editing buffer. This is a pretty ham fisted procedure and also very annoying. Obviously a better way would be to have all 30 User Presets accessible at all times, as you would normally find on a synth or sampler and would enable you to quickly and easily step through your User Presets trying out different CV/GATE configurations and set-ups. I did mention this quirk (plus a few others) to the designers who couldn't really see a problem with it, however they did say (at my request) that the next software update may include the ability to access User Presets via MIDI program changes and the ability to save and load Presets as MIDI SysEx dumps. In fact the designers are quite open to any user suggestions and can be contacted through their Web site, nice one!

So what's the verdict then? Well it has to be... guilty, of being a fine upstanding MIDI/CV interface. With the MIDI-CV7 hooked up to my analogue system I haven't had so much fun for ages. The rock steady clock output and wide ranging and stable CV tuning made my VCOs sound brand new and all those LFOs and Glissando, mmm pure heaven! It has an easy to use, logical operating system with 24 clearly labelled parameter pages to scroll through and enough editable parameters on offer to satisfy even the most industrious programmer, which can't be said of some 'budget' interfaces. Apart from the few points mentioned elsewhere, the unit was a pleasure to use. Controlling all 7 channels and the DIN Sync from a bloated MIDI sequencer file the interface worked flawlessly, without any hiccups or slowdowns. There's nothing quite like the sound of a bunch of analogue gear stomping along in full flow and with this interface you can certainly drive a lot of synths, modules and drum machines simultaneously.

In a way I suppose this could be a deciding factor, do you have enough analogue gear to justify using this unit to its full potential? You could argue that CV synths are a dying, if currently fashionable, breed of instrument and most professionals that own any CV gear are quite likely to own a decent MIDI/CV converter already, if so, is there room for another MIDI/CV unit in this pretty specialised area?. However if you need to upgrade an old interface (like me!) or you're serious about all this analogue malarkey and need one with a LOT of channels, then the MIDI-CV7 would make an excellent choice. It may not look as polished as the Kenton models, and if anything it looks bit 'Maplin', but the build quality is actually very good with a solid feel to it. There are enough CV/GATE options to satisfy most analogue users, plenty of real-time MIDI controllable parameters (see box) and of course the obligatory DIN Sync socket. I would like to have seen the option of a Wasp and/or DCB output and possibly a few channels with dual CV outputs but that would have pushed the price up, beyond the quite reasonable asking price of £449. The E.E.S. MIDI-CV7 is another of those essential studio tools that pop up occasionally, with just enough extra features or lower price to make them stand out from the crowd. As the guy in the TV ad says 'It does what it says it does on the box' and very well too, I might add.




30 user memory locations.
7 Note Polyphonic.
16 bit resolution on all CV channels.
Seven CV outputs, each fully programmable.
Seven GATE outputs, 5-13V positive or negative types.
Programmable Oct/Volts or Hz/Volts on each CV channel.
Programmable LFO on each CV channel.
Programmable Portamento/Glissando on each CV channel.
MIDI channels assignable for each CV/GATE channel.
DIN Sync24 output.
MIDI In/Out/Thru
Backlit 2x20 LCD.

Price: £449 incl. VAT

Cimple Solutions Professional Ltd.
Unit 2-17 Wembley Commercial Centre
80 East Lane, North Wembley
Middlesex. HA9 7UR

T-0181 904 4141
F-0181 904 1200

A fully featured, easy to use product with stable, wide ranging outputs. It may lack a few of the more esoteric options and elegant looks of some competing models but makes up for this by having seven of almost everything and a reasonable price. If you are looking for a pro spec, multiple output MIDI/CV interface then look no further.

Wide ranging and stable CV signal.
Logical, easy to use interface with a clear display.
Effortless calibration procedure.
Enough output options to satisfy most analogue synth users.
System software upgradeable.
Units can be cascaded for greater polyphony.
Internal power supply.
Reasonably priced.
Poor access to User Presets.
GATE channels always tied to CV channels.
No Wasp or DCB option.
No separate clock/pulse output.
No mini-jack connectors.
Very bright LED's are a bit distracting.

Once calibrated the MIDI-CV7 produces an extremely stable and wide ranging CV signal and in fact I couldn't believe my ears when I first calibrated it to some old Roland 100M VCOs, because they stayed in tune over a staggering 6 octaves. For the past 8 or 9 years I've relied on an ageing Groove M2CV interface and it has never been able to manage more than about three octaves before drifting hopelessly out of tune, even after the obligatory 15 minute warm-up (which of course the MIDI-CV7 doesn't require). Funnily enough a Roland interface and a home made version I used before the Groove also suffered the same problems and I've always assumed that the fault lie with the design of the 100M VCOs. Boy was I wrong! Using the MIDI-CV7 has breathed new life into my beloved system 100M which, since my only CV master keyboard packed up, was gradually turning into a glorified filter bank.

As if all these features weren't enough the MIDI-CV7 also has a number of parameters editable via MIDI and the ability to transmit a CV signal derived from MIDI controller information:

01-Contr. 7
02-Contr. 11
03-Contr. 19
04-Contr. 20
05-Contr. 21
06-Contr. 22
07-Contr. 23
08-Contr. 24
09-Contr. 25
10-Contr. 26
11-Contr. 27
12-Contr. 28
13-Contr. 65
14-Contr. 120
15-Contr. 121
16-Contr. 123
18-After touch
19-Pitch bend

01-LFO Modulation Depth.
02-Portamento Time.
03-As selectable CV.
04-As selectable CV.
05-Portamento Mode.
06-LFO Waveform.
07-LFO Speed.
08-Clock Divider, for LFO sync.
09-LFO Duty Cycle .
10-Pitch Range
11-As selectable CV.
12-As selectable CV.
13-As selectable CV.
14-DIN Sync Divider
15-Port or Gliss On/Off
16-All Notes Off.
17-Reset Controllers.
18-Valid MIDI Channel Off.
19-As selectable CV.

Each CV output can transmit a control voltage from the list below.
The CV information is derived from MIDI controller information:
Key Note, Oct/Volts.
Key Note, Oct/Volts + Pitch bend.
Key Note, Oct/Volts + Pitch bend + LFO Modulation.
Key Note, Hz/Volts.
Key Note, Hz/Volts + Pitch bend.
Key Note, Hz/Volts + Pitch bend + LFO Modulation.
LFO Modulation only.
LFO Modulation + Pitch Bend.
Pitch Bend only.
After touch
MIDI Contr. 1
MIDI Contr. 7
MIDI Contr. 11
MIDI Contr. 25
MIDI Contr. 26
MIDI Contr. 27

Copyright © 1997 Chris Carter / SOS Publications.