Gear Change: Siel DK-70

Before I move on from Siel products, I've got to talk about a synth I truly adore, and am sadly parting with. The Siel DK-70 is an 8-voice DCO analog polysynth in the vein of the Korg Poly-800. It has a built-in two track polyphonic sequencer (real time key-presses only, though it does apparently output MIDI) and a wonderful, though strangely implemented, chord memory function. It runs on 6 D-cell batteries (or C? It's been too long since I used batteries), and has guitar-strap pegs on each end. These are the only part of the construction which are actually made from metal, the case itself being manufactured plastic of a quality similar to a Roland SH-101.

The programming interface on the DK-70 is, again, similar to the Korg Poly-800. The parameters are listed on the upper right of the synth (same as the later CTS-2000, except without the membrane button/menu system), and one selects the parameters to edit via the same membrane push-button phone-style pad that one uses to select a patch. The membrane buttons of the pad, I should mention, are surprisingly high quality given the obvious budget mindset of the design, and have been in good shape on both of the DK-70's I've owned. I compare this to the two Sequential Sixtraks and the Sequential Split-Eight I've had, where the membrane buttons were in absolutely abysmal condition despite the fact that the hardware appeared to have been well cared-for. Age is probably not an issue with the DK-70's interface, although this brings us to the memory issue.

The internal memory of the DK-70 was obviously designed as a consumer keyboard, with the lions share of patch save memory reliant upon a cartridge which was offered with the keyboard, which apparently nobody bought, or at least kept. The internal patch memory consists of 40 preset patches, which are very same-y, though usable if the Siel sound is something you're looking for (i.e. if you bought the thing), and 10 user patches, which are not battery backed-up internally and require that one keep the D-cell batteries in the synth, similar to the Casio CZ-101. Keeping it plugged in via the power supply does not ensure that your patches will be saved. When the 10 user patches are reset, the internal rom refills them with the remaining 10 of the 50 preset patches.

That's not so bad, since the final ten patches of the 50 are quite good with a little editing, and editing is extremely easy for anyone familiar with analog synthesizers. The built-in patches are best described as 'standard analog fare' for 1985, though they do exemplify why Siel and other Italian manufacturers were relegated to a sort of ghetto compared to their Japanese and American competitors. The quality of the piano patches on the DK-70 is horrid even in comparison with the standard synth piano patches of the Korg Polysix from four years prior to the release of the DK-70. Strings, perhaps unsurprisingly given Siel's background with the SCI Prelude, strings are where the DK-70 shines. The oscillators have a warm quality which is immediately comparable to the Korg Poly-61, but the Curtis filters paired with the unique design Siel employed give it a clarity and subdued warmth which totally destroys any possibility of comparison with the Poly-800 in terms of sound. Pair this synth with a cheap 80's reverb unit, and you can create the warmest, most enveloping wall of strings, or the most proper techno bleep bass you've ever heard (especially with the Moog Killer modification on the filter which expands the resonance and gives you knob control for that and the Cutoff).

I've owned two of these, and just sold the last one due to money issues, so let me describe some of the issues I've run into.

First, the power supply is a terrifically oversized 12v ungrounded brick, similar to the bricks which came with the Atari ST 520. It can be very noisy, but since I'm not too familiar with electronics I couldn't explain the factors which contribute to this. My building has a truly terrible electrical system, but behind a surge protector power-strip which shared power with my mixer and most of my other equipment, there was very little noise (caveat: my mixer is a first-gen Makie CR1604, which may have a noise floor above that of the DK-70, or there may be some kind of electrical equivalent of audio frequency cancellation, the correct term escapes me but it's the sort of thing that you deal with when miking a drum kit in the studio). However, when I brought the Siel into the audio studio at my university to allow my friend to use it as backing for a track we were working on, it had a terrific amount of hum. Here again, the caveat would be that I don't know how well that studio is wired and we were using it for something which they apparently never anticipated it would be used for.

Second, the keys tend to degrade over time in a fairly common but strangely unpredictable way. In most of the analog synths that I've owned, keys degrade and fail because the mechanism of the key contacts degrade a very slow rate between the contact and the conductive rubber plunger which the key presses down upon them. It can happen through frequent playing, where the rubber plunger wears down simply through overuse, or, more often, because dust accumulates on the conductive plunger and prevents full contact. However, the DK-70's keyboard is, and I state this having only used two of them, very, very cheap. There seems to be about a millimeter of space between the keys. I've only seen something similar with a quite well-worn Korg Polysix, and on that a simple cleaning of the contacts worked perfectly. With the DK-70, it seems to have been a point of the inexpensive design, possibly reusing a keyboard structure from another more expensive synth. The keys are slightly more mushy than other keyboards, probably due to the cheap feel of the keys themselves, which allows dust to act in different ways on them. A key pressed a certain way will not connect, but if massaged enough or if pressed in a different way will connect perfectly. Further caveat would be that I never bothered to try to clean the contacts, as the DK-70 responds very well to MIDI and I have been using another synth as a controller keyboard the whole time I've owned them. I don't think this problem poses any real issue, and if it does there are several cheap fixes in the case that a simple disassembly and cleaning with a q-tip doesn't work. If you have this problem with this synth or any other, look around for some Wire Glue or Conductive Paint (the former is cheaper and just as effective in my experience).

I would highly, highly recommend the DK-70 for someone in the market for a new analog synth to add to their established MIDI rig. On it's own, it provides wonderful sounds, but sampled it can provide an entire palette of analog-style patches to warp and alter which will sound like nothing which has come before.

Gear Change: Keytek CTS-2000

At the recommendation of more than a few friends (and since I'm not able to upload music from any new rips I might make) I'm switching gears and will post my thoughts/reviews of music hardware that I own or have owned in the past. I've spent the last seven or eight years buying and selling synthesizers on eBay, keeping those that I liked and selling those that I either disliked, couldn't afford to hang on to, or simply needed the money to buy the next synth that caught my fancy. The first of what I hope will be many posts is dedicated to the rarest synth I've ever owned, which also happens to be my current favorite as well as the keyboard which easily wins the award for 'the synthesizer with the least information available,' the Keytek CTS-2000 (second place goes to the Elka EK-22, which has a superb write-up by legowelt and a Vintage Synth Explorer page all it's own).



Keytek was the final moniker of italian synth manufacturer Siel, who produced some of my favorite synthesizers (primarily the DK-70, a beautiful example of the sonic qualities of italian synths as well as of the poor quality which ghettoized them compared to the japanese and american offerings, but to give them their due I'll also mention the Opera 6 and the Mono). Siel was facing bankruptcy in the mid 80s, and their budget synth lines in the later DK double digit series couldn't buoy them up above the ravages of the post DX-7 synth market. Luckily for them, Gibson were looking to expand beyond the guitar markets into keyboards, so along with Oberheim the italians were purchased with an eye towards remaking their brand and exploiting their unreleased synthesizers. In much the same way as Yamaha invested in Korg in order to enable their survival prior to the release of the Wavestation and the M1, Gibson hoped that the engineering division that produced the superb DK-700 polysynth as well as several other extremely successful synths just a few years before (to this day rumors abound that Dave Smith or Bob Moog himself designed one or the other of the Siel line) would pay off.

Unfortunately, Siel's unreleased line didn't quite live up to that hope. Where Yamaha could simply license Korg their FM technology until Korg could exploit the knowledge of the engineers they hired away from Sequential Circuits after their collapse, Gibson had no familiarity with the synth market and Siel apparently had a completely fucking terrible bunch of engineers designing the interfaces for their gear. I mean, just godawful for the time. Not so terrible for us today, in certain ways, kind of.

Siel was rebranded as Keytek under Gibson, and they released a series of horrifically outdated products, with a single exception. They produced the Keytek MDP-40, which I owned for a while as the Siel MDP-40, which was a preset drum machine with poorly sampled 8-bit drum sounds and ultra-generic preset patterns, saved only for it's ability to sync with MIDI clock and ability to play each sample by the non-velocity sensitive pads as well as through MIDI notes (I should mention that I never tested this). Also in the product line was the CTS series, which consisted of the CTS-1000 preset keyboard, the CTS-2000 "Cross-Table Sampled" synth, and the CTS-5000 rackmount piano preset unit. The 1000 is reportedly a Casiotone level preset keyboard with no editability and unknown features (there's zero information about it out there), and the 5000 is a fairly respectable for 1987 electric piano unit aimed at the Roland MKS-20 market. The CTS-2000, however, is a true gem in sound and a prime example of bad design.

The architecture of the CTS-2000 is rather impressive to an analog synth aficionado: two sampled waveform oscillators (OSCs from here on), with two envelope generators (EGs) for tuning and frequency, a deliciously warm 24db Curtis Digitally Controlled (analog) Filter, with two Digitally Controlled Amplifiers and three more independent EGs for the two DCAs as well as the DCF. It also includes internal stereo mixing with level controls and eight placements across the stereo field and is capable of five part multi-timbrality along with it's eight voices. This is both a tremendous point in favor of the 2000, and an hilarious point against.

Before I get to that, I should also mention that the CTS-2000 features 6 faders (not including the volume fader) which are the primary controls of the synth settings, although there is the by-this-point standard up/down increment buttons. The programming works through a menu system on a 2X16 backlit LED, where each setting on a given menu is spelled out above the button on the right side of the keyboard, which matches to one of the 6 sliders on the right side, and to select a given function one must move the slider. Annoying, but slightly more hands on than on a Roland Alpha Juno or JX-3P, especially since everything changes in real time (that includes filter cutoff and resonance) and once you've selected the appropriate menu and placed the sliders to the setting you want, they'll match the existing setting. With the immediacy of the LED readout, it would work quite well for the analog freaks out there.

The bit of hilarity comes in here, once you've figured out how to actually do a little bit of fiddling with the internal presets. The CTS-2000 was designed with the future of MIDI in mind, and multi-timbrality was essential for any new synth in the marketplace of 1986/7. Unfortunately, the engineers of Siel/Keytek either didn't quite grasp how to make this a consumer proposition, were constrained by Sequential Circuits patents on multi-timbral analog equipment, figured that a market which bought 100,000 DX-7s wouldn't have a problem with a ridiculous interface, or were just pressed for time to put out a synth after the Gibson buyout: Either way, the CTS-2000 has one of the most ridiculously idiotic implementations of multi-timbral synthesis ever conceived.

The keyboard is five octaves. Each of the five octaves must be programmed individually. That is, each octave of the CTS-2000 acts as an individual synth which can play a different patch from the other four octaves, with the 8 shared voices able to change for each octave/note demand. It's kind of impressive for the time, if it weren't so incredibly stupid given that each octave must be programmed individually. Thankfully, there's a kind of copy-paste available, although it doesn't work quite right (it's a bit like loading a Roland sample bank on an Akai sampler or vice-versa, there's bits left out that you have to reprogram to get right). The end result, and apparent intent, was that the CTS-2000 acts as five different polysynths, each limited to a single octave and sharing eight voices among them, kind of like some digital version of the Oberheim 4-voice or Korg Mono-Poly , except you can assign each octave of the 2000 to any given octave, and each octave to any given MIDI channel. This brings me to the MIDI implementation.

In his commentary on the Elka EK-22, Legowelt mentions the MIDI implementation in particular. That is, he mentions that the thing drops MIDI notes when stressed too much. Like when you send two messages to it at once. The biggest weakness of the CTS-2000 lies here. The keyboard itself is absolutely wonderful, the action is easily the best I've ever played (and I'm comparing this to every model of the Korg Poly series, all of the Roland Junos, Kawai's K series, Sequential's Sixtrak, Split-Eight, and Prophet-600, even Akai's AX-60 and X7000), it just feels wonderful to play and the velocity response is nice and on point. I imagine this is the same thing people talk about when they say the Elka EK-22 plays like butter. I want to use this as my master keyboard, but that's where I run into problems.

When I set the CTS-2000 up as my master keyboard, I run into issues with the internal capability to keep up with MIDI messages. For example, the preset patch "JAKO-FIFTH" is absolutely going to be the foundation of a future track. The keyboard is divided so that the bottom two octaves are the JAKO solid bass patch and the upper three are a beautiful evolving analog-style fifths pad. When I try to play both patches at once, transmitting MIDI to my sequencer on two MIDI channels, the keyboard misses notes. That is, it literally misses notes that I play in real time, failing to produce sounds when keys are pressed. This explains why there is a MIDI On/Off button, as well as a MIDI Local/Remote button (I have yet to discern the difference between the two, since the MIDI Off setting should do the same thing as the MIDI Local setting does, but I'm not much of a hacker). This is a 'feature' that the CTS-2000 shares with the EK-22: the internal processor is fully capable of handling the various settings the keyboard itself was designed to allow, but nothing beyond that.

Having said all that, I'd like to move into the actual capabilities of the thing. The CTS-2000 has (according to the promo lit) 333 possible waveforms, these provide the basic sound which is processed through the analog filters and is shaped by the various envelope generators. The waveforms are divided into a series of three different sounds which are shared between the two 'oscillators'. The 'oscillators' provide a basic functionality for linking the three transitional waveforms together, a sort of attack/release for the transition between each sound. The resulting sound is comparable only with the implementation of multi-timbrality I described above. It's brilliant in it's own way, but terrible in comparison with similar synthesizers of the same period (namely the PPG and most other wavetable synths). It provides a good level of control over the transition speed between the waveforms, and what I suppose you would call the 'mixing' of the wave transitions is even and allows for very interesting pad sounds which would be impossible to reproduce on any other synthesizer. Add this in to the filtering capabilities and you've got an absolutely amazing source for pad sounds which couldn't be created any other way, even if sampled. I don't know how good the sysex implementation is, but I'd wager it's good-but-strange. If the sysex allows for external control of the waveform transitions as well as the other features (stereo placement control could be amazing), the CTS-2000 would be a monster easily surpassing the similar synths of the time.

The sampled waveforms are about what one would expect for the period, comparable to those found in the Korg DW series or the Kawai K3. Low bitrate, but when processed through the analog filters, very warm and a happy fit for mixing. The bass sounds in particular are phenomenal: the preset bass sounds are extremely usable, though they mostly suffer from being the bottom two octaves of a split with the higher three being some generic-sounding bit obviously aiming the patch towards one-man-band pub type situations (the JAKO-FIFTHS patch being the exception). However, that criticism was leveled at the 303/606 combo in it's time, so take it with a grain of salt. The bass presets are head-and-shoulders above the FM Solid Bass preset of the sought-after Detroit classic DX-100 or the Lately Bass preset of the TX-81z, and would easily hold their own against the M1 basses. The other samples tend towards same-ness, just as the Korg DW waveforms do, but the transitional nature of the design provides for a level of creative interaction which neither of the Korgs nor the Kawai K3 allow. The 'attack' of the sample transitions on the CTS can be set very fast or extremely slow, giving you the ability to provide a weird punchy bass blip or a long evolving lead.

My own taste in synth programming tends towards the moving pad chord style, and I really enjoy programming synths, so I'll advise against the CTS-2000 as a first keyboard. But for the heads? Get one of these if you can find it. I bought mine for $100, and I feel overpaid tremendously given the nonexistent market (I don't price synths based on what I feel they're 'worth', as anyone who has ever bought a synth from me will affirm, I value them based on the market price and essentially only worry about whether something is over-priced. That is, the less I pay, the better the deal, as opposed to "the less I pay, the worse the item.") The week after I bought my CTS from a seller in California, I saw a seller from Queens offering one for $200, which, I might add, sold for that price. I wouldn't pay more than $100 for one, but as I make more posts about synths in the future you will probably notice (especially in light of the above guiding rule) that I lowball prices.

Up next: Siel DK-70, Akai X7000, and possibly XoXBox.