The Dark Time had a failure. Not really sure why at this point, but when I started it up yesterday it showed an odd pattern of lights and was entirely unresponsive. Repeated power cycling. And I’ll admit that’s a kind of pretentious-sounding phrase especially as applied to something you do just switch on and off rather than go through a more macroscopic shutdown/startup process, but it’s a bit more concise than ‘turning off and on again’. Did nothing apart from eventually change the pattern of lights.

So I thought, let’s check the power supply. The Dark Time according to the labelling uses 12V AC and this is the original adaptor I got with it (though not Doepfer own-brand, which may be normal), and is also rated 12V output. It’s actually giving 16V no-load, which seems a little high. Some PSUs limit the voltage until they detect a load but starting up high is less common. But a little online probing tells me that some Dark Times were supplied with 15V supplies, so maybe this is in-range. Powering the thing with 12V AC from a lab supply makes no difference. ^[1]

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A quick and dirty drawing and translation for non-Cyrillic-readers of the main control panel of the Estradin Altair (Эстрадин Альтаир) 231. (A rough copy of the Minimoog built in Ukraine in the mid-1980s.) The drawing focuses on clarifying the points I’ve found confusing while trying to learn about the instrument, either due to my limited Cyrillic or the unexpected nomenclature.

There were different versions of the box lines and dials, and the original cap colours seem to vary. This concentrates on the words, ^[1] and doesn’t show one specific version of the rest. Or screws. For clarity, I’ve simplified the waveform shapes. It may not be exactly to scale or be too accurate about knob shape, as I’m working from some indistinct photos. (Hoping to get exact measurements one day.)

(Full size here).

Like the earlier Estradin 230, the Altair replicates most of the controls (if not the sound) of the Minimoog, but leaves off the output switch and has only a single key CV → cutoff switch. ^[2]

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Shall I say that DX7s need no introduction? Well there are more web pages than I’d try to count about them, so if you need an introduction, go get it.

The original DX7 to me was that sleek thing with membrane keys which, in 1984, someone I knew got hold of, praised the capabilities of effusively, and left me with unattended for a few minutes. Being sort of used to simple analogue synths, I thought, well, let’s see? And pressed a few membranes, managing to change what it was doing out of all recognition in a few short seconds, with no idea how to change it back. Up DX7 creek without a manual, nor any clue how I got there. I thought it would be best to just leave it rather than make things worse. Leave it at speed, before its owner returned. I never saw it again.

Clearly this memory has stayed with me. In fact it’s probably the exact reason why I prefer proper synthesisers, i.e. ones with a control for each parameter, that you can see, adjust, and then put back where you found it. Nevertheless, I’ve always thought that one day I would like to find out how to use the thing. One of my own, without the risk of wrecking someone else’s setup again.

So, here we have one of the DX7 updates, a DX7S, from 1987 I think, and in need of some attention. I’m not sure what’s wrong with it, but battery replacement is apparently wanted. Hopefully not much more than that.

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A summary of investigations into Hohner analogue electronic pianos and string machines. (To date. There have been some updates and more may happen.)

HIPs and Strings

Ephemeral photos of most of these instruments turn up occasionally in online sales; longer-term linkable references are given below. Different branding seems to have been used by Hohner in different national markets, however, so even if this list is comprehensive technically (which I can’t guarantee), there may be alternative names in some parts.

Drawings below are sketches intended to highlight the distinguishing characteristics of the instruments, rather than be exhaustively accurate. Or get the perspective right or anything. Slider caps in particular may vary even in the same model; so I’m not trying too hard to represent the exact types found — where they haven’t all vanished or been replaced.

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Side by side shots of the Korg SD delays, the -200 opened for comparison while I convert the -400 for 240V.

The SD-400 (brown) has the bypass, short/long delay option, swell, and ADT settings, but no tone control. I haven’t quite worked out which I prefer; the -400 seems to have a fixed filter; it’s smoother than the SD-200 (silver) on simple delays, unless you turn the -200 tone down. Maybe the -200 is better for harsher delays. The only online technical information I’ve found for them suggests they have roughly the same range of 30–400ms for the -200 and 25–400ms for the -400. Presumably the -400 should go lower on its Short setting, but it’s the same as the -200 on its Long setting. In practice, comparing these two, the -400 gets up to around 10% longer delay, but that could just be a calibration thing on one of them.

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