The Crumar GDS Restoration Blog...

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Re: The Crumar GDS Restoration Blog...

Post by ppg_wavecomputer » Mon Sep 29, 2014 10:51 am

MiK wrote: [...]
ppg_wavecomputer wrote:The old Schulze GDS looks so much better than I remembered (with beer and coke spilled over it, and cigarette ashes all over it). I guess the GDS keyboard controller that recently was up for sale on eBay was TD's old one, then (the seller was a bit secretive about it).
Did you mean eBay Germany, half a year ago? (And maybe a year ago, it was listed twice). If yes, that's mine now :) [...]
Congratulations. I was tempted to bid but I thought I couldn't afford yet another behemoth keyboard to gather dust in here :). I take it the seller was Mirko or someone else from the Synco crowd?

Is that a CS80 you are delving into? Looks familiar...

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Mon Sep 29, 2014 11:04 am

ppg_wavecomputer wrote:Congratulations. I was tempted to bid but I thought I couldn't afford yet another behemoth keyboard to gather dust in here :). I take it the seller was Mirko or someone else from the Synco crowd?
I also was a bit mislead by the description not stating explicitly that it's not a full GDS, just the keyboard. I paid too much for the use (or lack of) of this beast, but okay, it's ultra-rare and i will find a purpose, so i don't regret it meanwhile :)

I lost the communication with the seller as there was nothing of interest beyond basic eBay transaction handling (i asked where this thing came from and if there is a chance to get the rest of the system also, but he said he has no idea and no, it's all he had) and eBay also seems to delete messages after a while.

Checked the bank transactions - it's an Andre and the machine came from Berlin.
ppg_wavecomputer wrote:Is that a CS80 you are delving into? Looks familiar...
Good eyes :) Installed a MIDI retrofit in the CS80 of a friend some years ago, this is one of the photos he took.

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Mon Sep 29, 2014 11:18 am

A very nice man at a local metalwork fabricator has produced a quote to make a duplicate of the missing front trim plate on the keyboard console which is badly letting down its general appearance.

This will definitely be going ahead.

Speaking of the keyboard console - I had some fun last night trying to match up one side of the keyboard with the side view of the beast in a picture of Klaus's studio from many years back.

The results are interesting....

Image

I have spent this morning trying to work out what the heck the paint/metal surface finish is on the top of the GDS/IMS8000 computer which is badly scratched and has subsequently rusted in storage. The surface finish is like a crinkle texture but is only on the external surface despite the colour of the paint being identical on both sides leading me to think the plate has been embossed with a texture prior to painting.

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Tue Sep 30, 2014 11:41 am

Last night I scanned a rarely seen guide detailing the GDS keyboard console controls.

For those who'd like a more detailed look at the GDS I have posted both the original user manual in full and the guide here - download link via WeTransfer:

http://we.tl/BvfwjMDpwn

Get them while you can, they are both very difficult to find on-line.

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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Tue Sep 30, 2014 3:05 pm

Fantastic. Great to see this info. Some great diagrams in there, made with a typewriter/ ASCII terminal!

On the topic of ASCII, I noticed your screen grabs were from source. How do you grab the monitor output? Some kind of standard interface?

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Tue Sep 30, 2014 3:22 pm

madtheory wrote:Fantastic. Great to see this info. Some great diagrams in there, made with a typewriter/ ASCII terminal!

On the topic of ASCII, I noticed your screen grabs were from source. How do you grab the monitor output? Some kind of standard interface?
D'oh!... You got me..

I was coming round to this one... one of the bigger problems with the GDS at the moment is that almost comically the back of the CRT has at some point broken off inside the ADDS Regent 20 terminal complete with the neck pcb!

..bet that went with a pop... phhhssssssssssss....

Amazingly I have found a brand new equivalent replacement tube for this 35 year old museum piece but its expensive and is coming from the US. In the meantime I've been using a terminal emulator hooked up to the serial port on the IMS8000 host computer.

Last night I stripped down the terminal and cleaned it all out finding several small balls of tobacco inside (Klaus'??) and removed the monitor chassis. I tested the PSU in isolation and then powered up the remaining terminal electronics which, with the aid of a scope, appear to be initialising and producing sync and video signals.

As a parallel task I'm trying very hard to source a replacement ADDS Terminal but with the exception of one owner who doesn't want to part with his boat anchor I've not had any luck to date.

I really want to keep the system looking authentic hence why I'm putting some effort into returning the original terminal to life. It is after all the terminal Klaus would have sat in front of for hours on end (and the really bad screen burn definitely has a story to tell there - you can the GDS performance menu burnt into the phosphor!!.) It is also the terminal that is seen in many pictures of his old studio.

Image

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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Wed Oct 01, 2014 11:19 am

I think it would look cool with an LCD in there instead, but you're right it wouldn't be authentic.

Does your terminal emulator run on a modern PC? So is it possible to run the system from that? Again not authentic, but perhaps more convenient?

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Wed Oct 01, 2014 12:00 pm

madtheory wrote:Does your terminal emulator run on a modern PC? So is it possible to run the system from that? Again not authentic, but perhaps more convenient?
You get a terminal emulation for nearly every OS, even Windows has it's Hyperterminal included (at least it had, didn't see Windows for a while).

And then, there are some cool emulations that at least emulate the look of the old ones:

http://swordfishslabs.wordpress.com/201 ... is-coming/

But Dan is right, this exotic machine really deserves being restored completely - including the original terminal. Really bad that the CRT neck is broken :(

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Re: The Crumar GDS Restoration Blog...

Post by BrianK » Wed Oct 01, 2014 9:23 pm

I'm wondering if there is a REMOTE possibility that that Tangerine Dream controller keyboard could be made to work - you'd have to make PCBs (not easy but possible from scans and photos of ours) and stuff them, flash some ROMs etc etc. But considering what the system could be, you actually have the HARD PART, that controller. The rest is an old computer, which might be buildable...

We're working to share the software/discs and additional parts and info. I'm certain we'll have at least two highly functioning GDS systems after this...

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Thu Oct 02, 2014 6:07 am

BrianK wrote:I'm wondering if there is a REMOTE possibility that that Tangerine Dream controller keyboard could be made to work - you'd have to make PCBs (not easy but possible from scans and photos of ours) and stuff them, flash some ROMs etc etc. But considering what the system could be, you actually have the HARD PART, that controller. The rest is an old computer, which might be buildable...
While possible in theory, i don't plan to copy the original system. I will recreate it with current technology, so maybe this ends up with a small box that is attached to the DB25 connector of this keyboard, with USB to the computer, where you have Audio, MIDI any a serial terminal collection. Just as an example, my ideas are not complete to this level of detail. There already was a project like this, based on FPGA, my original idea. But as FPGAs have proprietary windows-only development environments, i still boycott them but go for generic micros, having enough experience with them.

I don't want to spam this thread with this recreation project (but i might create a new thread about it when the time is right), due to lack of time, there is not a lot to tell anyway currently. But i meanwhile carefully analyzed all the functional units (DK Synergy, not GDS, but this is just because there i have all the schematics, firmware and software sources and so, and later, it should be possible to adapt it to GDS-style with a small amount of changes) and even started recreating the heart of it, the oscillator board, with some lines of code.

This oscillator is a very fascinating design of a DSP running some simple microcode, built with tons of then-current logic gates and PROMs. It should not be a problem to recreate the functionality (not emulating the circuitry!) 1:1 with a modern Cortex-M micro. Using the original tables, the final results of the calculations will be the same, and after re-implementing the firmware and synhcs in C/C++, the firmware and the oscillator code can be integrates enough to get exactly the same behavior as the original, synhcs might end up with a wxWidgets based GUI, talking to the rest via USB.

But it will take time. The project it too complex to work on it from weekend to weekend, i need some weeks in a block for this, so it has to wait until the next summer vacation. And even then, it's not sure if not other stuff eats up this time once again. It's not that i started the DK Synergy recreation idea yesterday, i have this in mind since at lest 4 years. But at least i have the necessary materials since half a year now, so technically, i can start now, and from time to time, i take some hours and try something.

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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Thu Oct 02, 2014 11:35 am

So you're talking about making a Mulogix Slave 32, or an Atari AMY? Yes, that's a lot of work!

http://en.wikipedia.org/wiki/Bell_Labs_ ... ynthesizer
http://en.wikipedia.org/wiki/Atari_AMY

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Thu Oct 02, 2014 11:39 am

madtheory wrote:So you're talking about making a Mulogix Slave 32, or an Atari AMY? Yes, that's a lot of work
Not exactly, you can more compare it with a software emulation (which is possible with the code base also, a virtual GDS) interfacing to the original keyboard controller (which in fact will just talk MIDI later).

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Re: The Crumar GDS Restoration Blog...

Post by madtheory » Thu Oct 02, 2014 5:55 pm

Right. The AMY took a team of coders, and the Mulogix was made by two of the GDS people. Sounds like a big job to me. But it would be amazingly cool to have this synth in existence again!

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Re: The Crumar GDS Restoration Blog...

Post by masstronaut » Thu Oct 02, 2014 8:04 pm

That terminal is a beaut. Shame you didn't find any vintage balls of hash.

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Re: The Crumar GDS Restoration Blog...

Post by MiK » Fri Oct 03, 2014 8:54 am

madtheory wrote:Right. The AMY took a team of coders, and the Mulogix was made by two of the GDS people. Sounds like a big job to me. But it would be amazingly cool to have this synth in existence again!
And they both were hardware designs, while at least the Mulogix was based on the GDS/Synergy circuitry. I'm talking about most of the functionality being implemented in software. The hardware side is just interesting to have a standalone unit and to connect the original GDS controller to it.

It is possible to recreate the GDS/Synergy in pure software, as it's a fully digital synthesizer and modern computers are fast enough to easily handle this. And due to the ways APIs like CoreAudio or an USB audio device work, you can even allow jitter in the implementation, giving you some more flexibility in the algorithms to recreate the exact same functionality. You just might get 1-2 miliseconds more latency compared to the original.

For the effort - the main part is understanding the original design in depth to be able to create the necessary algorithms at all. But if i'm done with it, i will open source it if there are no legal reasons against it. But after this time, i don't think so, as i don't copy the hardware and if there were patents on the way this thing works, they should be expired since a while.

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