EES MIDI-CV7

Got lots of analogue synths? This could be your one‑box solution to bringing them into the world of MIDI. Chris Carter gets converted.

Sporadic sightings of MIDI‑to‑CV converters have occurred since MIDI keyboards first appeared in the '80s, 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 stable, reliable and feature‑laden units. At the moment Kenton are probably top dog in this specialised area, but EES — who aren't exactly novices when it comes to designing and building for the electro‑music industry either, with a creditable pedigree of building interfaces for C‑Lab — are hoping to muscle in with this new MIDI‑CV7 interface bursting with features.

Seven Times Seven

Each of the seven MIDI‑CV7 channels works independently and has an extensive range of programmable parameters. The system is menu‑driven, using a nice clear 2‑line x 20‑character backlit LCD; in its factory‑fresh state, the unit emerges from its box with 30 identical presets in user‑programmable memory locations. Four arrow keys allow you to navigate the system pages, and there are two buttons and a data knob for entering and changing parameter values. There are also nine (extremely bright) LEDs 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 — although this is a rackmounting unit, it has to be one of the smallest I've come across, only 1U high and 12cm deep (not including the somewhat superfluous front‑mounted grab handles). The crowded rear panel has 14 quarter‑inch 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.

Name That Tune

The erasable factory presets are configured as seven CV/Gate channels assigned to corresponding MIDI channels 1‑7, with each individual CV output programmed to transmit a control voltage containing note, pitch‑bend and LFO information, and each Gate output 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 presets, it is possible to use the MIDI‑CV7 straight out of the box, assuming your gear is compatible.

There are enough editable parameters on offer to satisfy even the most industrious programmer.""With the MIDI‑CV7 hooked up to my analogue system, I haven't had so much fun for ages.

However, to get the best out of the MIDI‑CV7, the first thing you need to do is 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; then you play a MIDI note at least two octaves higher and tune the upper range; the display will read 'OK', and that's it — piece of cake! The CV tuning range is very wide, an octave and a half at either end of the scale, allowing 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 it's particularly useful if you have a large collection of analogue synths or VCOs. There's also the bonus that any special patch or setup can be named and saved as a User Preset in one of the 30 memory locations.

Channel By Channel

There are a number of output options available for each CV and Gate channel (see the 'CV Output Options' box). For regular use, most channels will be set to Note+Pitch+Mod, which 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 zero to an octave up or down 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 number of programmable parameters available for each CV/Gate channel adds immensely to the versatility of the unit. Any CV/Gate channel can be assigned to any MIDI channel, and there's also the option of assigning multiple CV/Gates to a single MIDI channel. 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 or VCA, or to modulate a VCO pulsewidth. The only drawback here is that if a CV channel is programmed to transmit anything other than keyboard note information, 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, triggering analogue sequencers, arpeggios, ADSRs, sample and hold generators and even noise gates and effects units. This omission could be addressed with a future software update, though.

Roly Poly

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, but the follow feature is used when chords are played in Mono mode. As you release held notes, the next valid note of the chord, whether highest, lowest or newest, 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 it's released, even if a new note is played. Or there's Poly Priority New, which replaces the oldest note in priority with 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 that you can have up to 7‑note polyphony if you have enough VCOs, and additional MIDI‑CV7s can be cascaded for greater polyphony.

Lotsa Fun Oscillators

Having extra LFOs at your disposal opens up all sorts of creative avenues with analogue synths — 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, VCA EGs and even VC effects, the modulation possibilities are almost infinite. To find seven 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. 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 sync'ed 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 preset level, or introduced using a MIDI controller such as a mod wheel or aftertouch. I'd like to have seen a ramp waveform and possibly a sample and 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!

A Gliss Of Port Please

As I 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, it could be described as a basic type of arpeggiator. As in portamento, notes flow across the keys depending on which are held down, but with glissando this occurs in semitone steps. When Time mode is on, the time taken from one note to the next is variable (in millisecond steps) from a plod, plod, plod through to a fast trill. It would be nice if the glissando speed could be sync'ed 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 — and all in real time too. Great stuff!

In Sync

Default mode for the 5‑pin DIN Sync output is a standard +5V, Sync24 signal, suitable for driving pre‑MIDI Roland drum machines, Basslines and suchlike. There are options to change the sync trigger from a 'leading' to a 'trailing' edge and to enable a Clock Continue signal, as well as 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, 2 halves the speed, and so on. At its fastest setting of 1, the display also reads '96 Notes', which I assumed meant 96ppqn, but it probably refers to the MIDI resolution, as I couldn't get the Sync clock to produce an output faster than 24ppqn. This is a shame, as Korg drum machines require a 48ppqn clock and I'm pretty sure that some American drum machines used 96ppqn. Two LEDs on the front panel indicate DIN Sync Start/Stop and Clock activity, and could be useful tools for troubleshooting lost clock signals and dodgy leads.

A Load Of Old Saves

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 presets at all). On the review model, only one preset was immediately available for use; to access any others, I had to first load them 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'd normally find on a synth or sampler; this would enable you to step through your User Presets quickly and easily, trying out different CV/Gate configurations and setups. I did mention this quirk (plus a few others) to the designers, who couldn't really see a problem with it; they did say, though, that the next software update may include the ability to access User Presets via MIDI program changes, and 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, which is nice.

Silence In Court

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, stable CV tuning made my VCOs sound brand new, and as for all those LFOs and glissandos... pure heaven! The MIDI CV7's operating system is logical and easy to use, 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 seven channels and the DIN Sync from a bloated MIDI sequencer file, the interface worked flawlessly, without any slowing down or hiccuping.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 the CV7 to its full potential? You could argue that CV synths are a dying breed of instrument (even if they're fashionable at the moment) and most professionals who own any CV gear are quite likely to own a decent MIDI/CV converter already, so is there room for another MIDI/CV unit in this specialised area? However, if you need to upgrade an old interface as I do, or you're serious about all this analogue malarkey and need a unit with a lot of channels, then the MIDI‑CV7 would make an excellent choice. It may not look as polished as the Kenton models — if anything, it looks a bit 'Maplin' — but the build quality is actually very good: it has a solid feel. There are enough CV/Gate options to satisfy most analogue users, plenty of real‑time MIDI‑controllable parameters (see the 'Real‑Time MIDI Control' box) and, of course, the obligatory DIN Sync socket. I would like to have seen the option of a Wasp or DCB output, or both, and possibly a few channels with dual CV outputs, but that would have pushed the price up beyond the quite reasonable figure of £449. The EES MIDI‑CV7 is another of those essential studio tools that pop up occasionally, with just enough extra features or a low enough price to make them stand out from the crowd.