The Crumar GDS Restoration Blog...

Discussions about anything analog, digital, MIDI, synth technology, techniques, theories and more.
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madtheory
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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Mon Dec 22, 2014 12:29 pm

I reckon it's Tomita's Cosmosynth next ;)

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HideawayStudio
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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Sun Jan 18, 2015 8:57 pm

Finally after much detective work and frustration I've found a modern serial terminal emulator that actually supports ADDS Regent 20 terminals so that Brian can run his GDS without having to have the real thing!!

Image

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It won't be long now before both beasts are returned to their owners - I will definitely miss them after all this time working on them!

Image

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Re: The Crumar GDS Restoration Blog...

Post by abruzzi » Mon Jan 19, 2015 6:50 am

Man, someone should dump all the rom images and write an emulator for those of us that will never see one live...

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Mon Jan 19, 2015 7:03 am

abruzzi wrote:Man, someone should dump all the rom images and write an emulator for those of us that will never see one live...
I have this on my schedule, just waiting for the next vacation to find time for this :)

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Re: The Crumar GDS Restoration Blog...

Post by ppg_wavecomputer » Mon Jan 19, 2015 11:44 am

HideawayStudio wrote: [...] It won't be long now before both beasts are returned to their owners - I will definitely miss them after all this time working on them! [...]
I'll give you the accurate shipping address for the Schulze unit...

Stephen
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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Thu Apr 02, 2015 4:17 pm

Now that both GDS restorations are complete with Brian Kehew's beast already on its way back to LA from the UK I wanted to pass on my sincere gratitude to those who have helped to make this project possible.

I am hugely indebted to the following people for playing their part in assisting, no matter how large or small, in the restoration of two out the three world’s surviving Crumar G.D.S.

Mercer “Stoney” Stockwell – original designer, provided schematics and much technical advice
Hal Alles – original designer, sent me original patents, high speed digital oscillator description
John Strawn – original manuals - interesting project background information
Jerry Kaplan – original firmware - project background, introduced me to Hal Alles
Laurie Spiegel – very kindly send me some rare footage of Max Mathews and Hal Alles
Wendy Carlos – for her support & very kindly sent me pictures of her GDS and front panel overlays
Michael Kukat – custom MIDI Interface, drawing up the front trim strip on his GDS keyboard (ex Chris Franke)
Ken Waywell (GW Engineering Ltd, Trowbridge) – Fabricated new metal front trim strip
Sunbase Ltd, Swindon – bead blasting and powder coating
Chris Pretlove (CM Pretlove, cabinet makers) - performed the superb cabinet restoration on the KS GDS
Littlediode Ltd – sourced a number of more difficult to source replacement NOS ICs
Farnell Ltd – replacement capacitors, IC sockets
Jean-Bernard Emond – helped to convert the 50 way Shugart I/F to 34 way for HxC retrofit
Jean-Francois Del Nero (HxC2001) – helped to prepare the first IMS8000 8" CP/M disk images for HxC
Przemyslaw Krawczyk aka Lotharek – supplied the superb HxC Rev.F Disk Emulators
John Leimseider – for his continuing support resurrecting all things vintage
Brian Kehew – supply of a large collection of Barry Gould’s GDS Disk collection for imaging
John at Vintage Micros – Replacement Apple Lisa Cherry Foam & Foil keyboard contacts
Ian Primus – Assistance with CRT Replacement for ADDS Regent Terminal
Peter Edgley – An IMS8000 owner - Comparing notes over IMS8000 IPL Boot ROMs
Daniel Beardsmore – Help with Cherry Keyboard Foam & Foil contact identification
Will Kranz (Vintage Computer Forums) - ADDS Terminal Identification
Herb Johnson – Assistance with 8” Shugart disk drives
John Dumont, Andromeda Research Labs (supply of EPROM+ programmer for 2708s)
Richard Thwaits (help with locating IMS8000 IPL ROM binaries)
John Monahan (Owner of the superb S100computers.com site) – IMS8000 manuals & schematics
Jase Furneaux (Flightcase Warehouse Ltd) – Custom flight cases
Rock-It Cargo – Shipping Brian Kehew’s monster to and from the UK to LA
Mark Murray, Laser Lines – 3d modelling and rapid prototyping the broken key actuators
Stephen Parsick – providing some very interesting background on the KS GDS
Mark Vail – providing some interesting background on the GDS early in the project
Peter Forrest – for his support throughout the project
Jolene - as ever, for putting up with my endless obsession to return mountains of vintage gear to life!

In Memory Of...

This project is dedicated to the memory of my father Dr John Anthony Wilson and Professor Max Mathews both scientists at Bell Labs, Murray Hill, NJ throughout the 70s. BTL’s extraordinarily dedicated and passionate staff worked tirelessly over the decades to bring us so many inventions and scientific discoveries that have shaped the modern world as we know it today.
Last edited by HideawayStudio on Tue Aug 25, 2015 1:06 am, edited 9 times in total.

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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Thu Apr 02, 2015 4:42 pm

Bell Labs is in the blood. That's amazing. :)

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Re: The Crumar GDS Restoration Blog...

Post by BrianK » Sat Apr 18, 2015 4:32 pm

Nicely the GDS system returned to Los Angeles, with the help of RockIt Cargo, who are the most experienced movers for musical sound gear. I've used them for years, especially with tough things like this, or a Mellotron MkII I once had sent to LA from Scotland. Best thing is to tell them "there's no hurry" - as it can then wait until another shipment is planned and your shipment rides along with it for less cost.

Sadly - I picked up the system 2 days before I leave for a 6-week tour! So no time to plug and play, but it looks quite amazing, nearly new condition again. Such a superb restoration and can't wait to play and post some audio/video. Back home in June....

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Re: The Crumar GDS Restoration Blog...

Post by desmond » Sun Apr 19, 2015 9:37 am

BrianK wrote:can't wait to play and post some audio/video.
Please do!

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Mon Apr 20, 2015 9:59 pm

BrianK wrote:Nicely the GDS system returned to Los Angeles, with the help of RockIt Cargo, who are the most experienced movers for musical sound gear. I've used them for years, especially with tough things like this, or a Mellotron MkII I once had sent to LA from Scotland. Best thing is to tell them "there's no hurry" - as it can then wait until another shipment is planned and your shipment rides along with it for less cost.

Sadly - I picked up the system 2 days before I leave for a 6-week tour! So no time to plug and play, but it looks quite amazing, nearly new condition again. Such a superb restoration and can't wait to play and post some audio/video. Back home in June....
Hi Brian,

Glad you like it - both machines were a true labour of love to resurrect but to see and hear the final results was hugely exciting for me. I feel your frustration though... that's a long time to wait.

All the Best,

Dan.
Last edited by HideawayStudio on Tue Aug 25, 2015 1:01 am, edited 1 time in total.

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Tue Aug 25, 2015 12:41 am

Huge excitement here...

Before the beast is finally sent to its new home back in the US we were set one final challenge...

With the help of an exceptionally talented engineer in Germany, who has considerably better firmware programming skills than I, our challenge to design a MIDI interface for the KS GDS has come to fruition!!

Image

Although the GDS is an all digital instrument, it predates MIDI by several years and so the task was to basically spoof the serialised data from the key and pot scanners to and from the keyboard console. This is no easy task. The timings are really quite critical and there are an awful lot of pots, switches and keys to scan.

The solution was eventually based on an STM-32 processor running many times faster than the poor old Z80 running then entire synth!! It turned out to be beautifully elegant solution too consisting of a small metal box plugged in-line with the 25-way umbilical from the main System Unit to the Keyboard Console.

Well after some slightly tense moments making last minute tweaks to the firmware (the firmware has had to be developed off site away from the GDS which makes the undertaking all the more impressive!) the MIDI interface has successfully driven the beast rendering not only a full set of five-octaves but with full velocity sensitivity, pitch bend and sustain pedal... in both directions!!

And if that wasn't enough... any slider can be read and written via midi!

I nearly fell off my chair... and was equally delighted to receive a nice email from Wendy to say she was very impressed as she'd been told back in the mists of time that such a retrofit was near impossible.

Its quite strange to think this beast was build in the US, shipped to Germany in 1979 and is only now returning to its mother land to enjoy an exciting new chapter in its life...

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Tue Sep 08, 2015 3:35 pm

The Big Farewell...

Well after approaching a year on since I first embarked on restoring the 1979 KS GDS I have finally undertaken the last few tests including flashing and verifying Michael's latest firmware for the custom midi interface. The beast has been placed in its three large shiny new custom flight cases ready to begin the long voyage to its new owner in the US and I must admit feeling just a little emotional fastening down the lids.

During testing I made a final test recording of a live improvisation - this time via the Custom Midi Interface:


Well here's to an exciting new future for this 36 year old digital monster!

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