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Yamaha DX7S repair notes

Posted under Musical Technology at .
Tags:DX7S, hardware, instrument, repair, synthesiser, Yamaha

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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Red Dock

Posted under Miscellanea at .
Tags:photographs

Rumex obtusifolius leaf on grass Rumex obtusifolius leaf on path

Rumex obtusifolius

Doing well this year. Or at least, doing red.


Got Me

Posted under Other Technology at . Last updated 2022-07-24 02:52.
Tags:drive, hardware, security, software

got U

I’m trying to work out what happened to someone’s disk. This is one of a rotating pair of external drives used to backup an Ubuntu laptop. One of the pair, Backup 2, failed to mount the other day. I confirmed the problem and ran a backup to Backup 1. I now think that may have been a mistake, but we’ll see.

I tried fsck from the administrator account with no result, but noticed along the way that Backup 2 is seen as a single exFAT partition, which seems a little odd as I’d have expected ext3 or ext4.

Switching over to an OSX laptop where I have a better range of tools to hand, I can confirm that it reads as GUID/exFAT. But a look at it with a sector editor is puzzling. I see nothing in sector 0. Moving on to the sector 1 I have what looks like an EFI header so that should be fine. Sector 2 seems to be part of the same system. And I went back to 0 but this time scrolled down. That helps.

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A Spotter’s Guide to HIPs and Strings

Posted under Musical Technology at . Last updated 2022-05-05 17:11.
Tags:artwork, ELEX, ELKA, Hohner, Logan, piano, reference, string machine

A summary of investigations into Hohner analogue electronic pianos and string machines. (To date. Not planning any updates at this point, but you never know.)

Not long after the technology became reasonably affordable, Matth. Hohner AG sold several electronic piano and string machine models under their Hohner International brand, apparently aiming at cheapness and portability compared with their acoustic and electromechanical keyboards. Most of these were either rebadged ELEX (Excelsior) products or perhaps Hohner-inspired modifications of them. Some were rebadged ELKA and Logan instruments, and they produced a couple of their own designs. [1] (Hohner did also produce organs, bass keyboards and pedalboards, acoustic and electromechanical piano-like instruments amongst others, but that’s not today’s topic.)

The plethora of these instruments from different manufacturers, some sold as Hohner, some not, some easily distinguished, some not, some modified either inside or out over their production span, has led to a certain amount of confusion in the years since, and poses a puzzle for people interested in obtaining and/or repairing them. But perhaps it’s possible to construct a comprehensive overview which will allow them to be identified and distinguished?

[...]

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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Honour

Posted under Miscellanea at .
Tags:politics, satire

The Russ’s children are a wild bunch. We knew that all along. They’ve never been easy neighbours, though sometimes their parents were our friends. But yesterday we heard a scream from the little sister and wondered what it was now. Turned out that the biggest brother was dragging her into a cage he’d built. She’d been trying to get out and meet people, and the brothers didn’t like that. The littlest of them was always too small to dare to do anything himself, and too scared to talk to anyone or to disobey. So he’d helped build the cage and kept quiet.

We wondered what to do. Could we, should we, do anything? Sometimes everyone knows what’s going on, but no-one says anything. This wasn’t the first time she’d been dragged into the house and tied down, while Big Brother did whatever he wanted with her, and the Little Brother sat and watched, giggling to himself about the things he’d do when he grew up. How she got over that and still had enough nerve to talk to anyone, I don’t know. Perhaps she wants to believe that it’s good to be friendly, so long as people are friendly to you.

But this time I don’t know. I’m afraid. I’ve heard of it happening before in other villages. Maybe they’ll just tie her to the bed again and Big Brother can use her like before. Or maybe he’s so crazy about her, so mad that he’s not the only thing in her world. Maybe it’ll happen this time. Maybe he’ll say, it was an honour killing. And all the people looking for excuses will just say, well, honour. Yes, that’s important, isn’t it. It’s traditional. It’s their family business, after all.

Stop looking at me like that. You’re not helping.


Korg SD pictures

Posted under Musical Technology at .
Tags:BBD, Korg, musical equipment, photographs, SD‑200, SD‑400

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

Korg SD-400 and SD-200 front panels

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.

Korg SD 200 and 400 open

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