The Crumar GDS Restoration Blog...

[MiK]

Awesome job. Congratulations!

I have a large box of keyboard to throw away, if i find the time over the weekend, i will scan through them if there is something with similar key contacts, if so, i'll throw it in your direction :)

[HideawayStudio]

Just finished recapping the last S100 bus card in the IMS8000 host CP/M computer today - the floppy disk controller...



Each card is not a huge job to recap given the right tools but its somehow curiously satisfying to undertake...



I then used the opportunity to power up the full system with the newly resurrected original ADDS Terminal for a couple of hours.

For the first time this has enabled me to enjoy the user interface on the original serial terminal without having to endure a sea of misinterpreted control characters and failed screen clears. It also feels much more apt to be using the beast on an ancient terminal which eagerly beeps every time a slider or control knob is activated...



Lord knows how many hours this beast had run up in the hands of its original owner but judging by the severe screen burn on the original tube which I removed last week I'd say a h**l of a lot!

...you can actually just about read the lines of the main GDS Performance page in screen burn!

A quick picture of the full system together as one before cosmetic restoration commences.

[Dr. Phibes]

Looking good!

[HideawayStudio]

It always fascinates me how some materials seem to last forever (Bakelite being a nice example of a supremely stable substance) and some go depressingly unstable or simply crumble into oblivion with age...

Yesterday was a particularly messy example of this...

Unfortunately the 32 long throw sliders on the GDS have rubber dust guards and these really have not faired well with age. At first I was hoping to save these but on closer inspection the rubber had become so perished that it was literally crumbling with several fragments already sitting inside the slider mechanisms.



I completely stripped down the front panel assembly on the keyboard console only to find that the rubber strips where integral to each slider rather than a single large dust guard sheet sandwiched between the sliders and the underside of the front panel as I was expecting.



I removed a slider and found it dismantled in a very satisfying manner. The sliders themselves are clearly quite decent quality.



A fair amount of heat was required to remove the slider from the pcb so on determining that it was in fact possible to remove the rubber strips without dismantling it I decided I wasn't going to take the risk of removing them all.



The resulting exercise resulted in a frustratingly tedious task of gently peeling and scraping a horrible black sticky mess from each slider.

After taking the opportunity to polish the empty front panel the reassembled console minus the multitude of wonky rubber strips is definitely looking better.

A quick test with the KPTEST utility confirmed that all 32 sliders were working as they should.

[HideawayStudio]

Now that I have an original working 1979 ADDS Regent 20 terminal that is correctly interpreting the extensive use of cursor control on the GDS I managed to program my first sound patch in the Voice program and went on to record a quick improvisation.



What has really hit home is how responsive this early digital polyphonic wonder is to velocity and playing style. There is a tremendous amount of control over the dynamic range. There is also a lot of scope for modulation with independent 16-stage loopable envelopes for each of the 32 digital oscillators.

[HideawayStudio]

It is thought 10 GDS Systems were built. I can account for the following 5 examples and their original owners:

1. Klaus Schulze (Death of an Analogue. Here in restoration, UK - 1 of 2 EU spec units)
2. Chris Franke (Tangerine Dream. In Germany. Sadly only the keyboard console survives - 1 of 2 EU spec units)
3. Brian Kehew (Believed to be an ex demo unit. Currently in the UK awaiting overhaul)
4. Wendy Carlos (Tron Soundtrack - Very much still with Wendy in NYC)
5. Stoney Stockwell (On original design team - Sadly GDS is no more - had a very unfortunate end!..)

UPDATE: I now have a potential lead on a 6th system in the US.

So one has to ask the question - where are the rest of them? Do they even exist??

In all seriousness - if any of you have the slightest notion where there might be more of these beasts please let me know as I'm very curious to know where they all ended up.

...and now, all the way from LA on a cargo plane, a second GDS is joining the restoration effort here..

Makes you wonder how long its been since two GDS systems were sitting side by side!

[madtheory]

...and now, all the way from LA on a cargo plane, a second GDS is joining the restoration effort here..

Awesome! What was the story with Stoney's one?

[HideawayStudio]

...and now, all the way from LA on a cargo plane, a second GDS is joining the restoration effort here..

Awesome! What was the story with Stoney's one?

I almost can't bring myself to say...

It stood several days outside before it ended up in landfill...

[synthroom]

Which landfill, and how far down???

Did you hear about some people that figured out where all the "ET" Atari games had been disposed of when the game was determined to be so bad that it could not be released for sale??
http://www.cnn.com/2014/04/27/tech/gami ... ideo-game/

[ppg_wavecomputer]

...and now, all the way from LA on a cargo plane, a second GDS is joining the restoration effort here..

Awesome! What was the story with Stoney's one?

I almost can't bring myself to say...

It stood several days outside before it ended up in landfill...

Which is the more devastating as he had announced in KEYBOARD magazine that he had a working GDS in his basement, free to the one who would come and collect it.

I guess this sounded so unbelievable that nobody bothered to ask whether he was for real...

Stephen

[HideawayStudio]

...nervously awaiting the arrival of Brian's GDS today all the way from LA in three large flight cases!

Two full GDS Systems under one roof?... eek, now that really is a rare occurrence!

[HideawayStudio]

The 2nd beast has arrived here in the UK from LA in an impressive flight case you could practically drive a tank over!



This is the original case the sales team at Crumar/MTI/DK would have used to haul the beast around the country as a promotional unit.

This houses the IMS8000 computer (which houses the GDS synth itself). The keyboard console and serial terminal are in their own cases.

[BrianK]

Yes, Stoney had announced his unit for offer, but no one knew about the announcement. We all learnt of its "passing" too late! Somewhere, there is also a landfill with over 1,000 Roland TB303s outside of Los Angeles, "new" in box!

I'm glad my unit has arrived safe and sound. I think the alligator case for the keyboard section is more photogenic, though! All the cases will get a re-foam when I get them home... Unless you have someone close by who does that? they are on the verge of liquefaction!

[HideawayStudio]

I'm glad my unit has arrived safe and sound. I think the alligator case for the keyboard section is more photogenic, though! All the cases will get a re-foam when I get them home... Unless you have someone close by who does that? they are on the verge of liquefaction!

There is no doubting the flightcase the IMS8000 was shipped is impressively robust but sadly the foam is indeed slowly turning to goo. It is such a shame foam does this with age.

Speaking of things deteriorating with age...

Very unfortunately a serious problem is rather too apparent in Brian's GDS.. (but curiously not apparent in the KS GDS) 26 keys are not working because the plastic key contact actuator spigots (which also carry the track the torsional return spring runs in) have gone brittle with age and fractured at the point they screw to the back of their metal levers. It is worth pointing out that the force applied on the plastic at this position in the key mechanism is limited by the end stops so I fail to see how this is the result of excessive key force.





I have spent quite some time now trying hard to identify the key action in the GDS with no success. Rather like a VW Golf carries some design/build hallmarks shared with an Audi A4 but doesn't actually share much in the way of common parts, the keybed in the Elka Synthex looks like it could have been made by the same company (FATAR?)



I have already sent out photos of the key action to several fellow synth engineers now and we've all drawn a blank. There is some general agreement that due to the metal key levers being almost twice as long as most synth actions this might actually be a keybed from an e-piano. What we can say pretty much for sure is that it is highly unlikely the keybed was custom made for the GDS as the tooling costs would have been prohibitive.

If anyone recognizes this key action and/or knows of an instrument with a very similar/identical one (apart from the DK Synergy) then please let me know.

At present it is starting to look like the only way we're going to obtain more parts is to 3d model them and print them on an FDM rapid prototyping machine in ABS unless we get lucky and find a donor keyboard from a different instrument.

[ppg_wavecomputer]

How about the Crumar DP electric pianos (or the Baby Grand, perhaps)? They were later but...

Stephen