Author Topic: the e/g computer - actually a direct to disc recording system  (Read 1805 times)

Konnektor

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the e/g computer - actually a direct to disc recording system
« on: November 06, 2013, 08:20:23 PM »
hi guys,
one of the first decisions would be to define the border between existing SSL and new electronics
i could see the use of existing SSL interface cards rather than designing an entirely new system - here's why

the existing computer is actually a hard disk recording system with 12bit resolution and up to 128(?) i/o lines
the voltages on the in and outputs are analogue and range from 0V to +10Vdc
0V (fader down)
5V (fader up)
10V (channel cut)

so you could probably use any existing daw (with slight modifications) to substitute the computer!

some years back i thought of using some of the SSL computer cards and interfacing them to a new box, rather than starting from scratch at the ribbon connectors
hardware in small quantities (even a couple of 100 units) is costly
to incorporate the SSL ribbon connectors onto a pcb takes up lots of space (which is the factor that defines it's price)
and everything is there already

the ribbons carry analogue voltages from/to the console, so for a fully digital (cheap and easy) solution you'd have to replace the vcas in every channel for digitally controlled gain elements
this would be expensive, time consuming and change the sound of the desk dramatically - but not for the better
you'd need to move digital serial information through the fader lines which would be audible - you can probably hear what i mean when using total recall to scan the desk
i personally would not consider any solution down that line

the actual interface cards for analogue i/o and leds+switches (trim/abs leds + their adjacent status switch switches) are widely available for reasonable prices and can be serviced easily
most folks already got them anyway

the analogue output cards contain sample and hold circuits for every channel - to come up with a substitute could be costly
they were designed to respond quickly enough (= they support fast fader moves) + also cater for the largest number of channels
the 'sample and hold' circuit buffers information (in our case the level of a channel)
the automation computer outputs updated information periodically (i.e. it updates every channel within specific intervals)
i guess the value of that frequency relates to the channel count which has to be set in the setup pages of the e/g series software
i actually thought that very large consoles respond more sluggish
maybe a modern processor could get away without s&h..?

for me the 12bit (1024step) resolution is no bottleneck either - so many of the worlds best sounding tracks got away with it

like i said, these i/o cards can easily be maintained
it's the processor and floppy drives (+ controllers) which eventually could create problems


i'm quite confident we could come up with an interface circuit which translates the information to a commonly used protocol - based on ethernet or something?

but then there's the software bit..
to make use of this information, sequentially record it with sufficient resolution, rock solidely linked to smpte t/c, represent it graphically + provide a gui for editing and control the transport of the daw

needless to say, another requirement is to provide up to date insults on user errors  :)


just my thoughts..cheers, werner
« Last Edit: November 06, 2013, 08:24:59 PM by Konnektor »

Artur D'Assumpção

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Re: the e/g computer - actually a direct to disc recording system
« Reply #1 on: November 06, 2013, 08:51:02 PM »
Hi Werner,

Thanks for your valuable opinion as always.

I think that we should come up with a solution that replaced totally the old computer, which means no cards from the computer would be used. This would be important to accommodate users that don't have a computer and these old cards are not getting cheaper. On the side of the console we would maintain intact all the electronics and use the already existent flat cables.

From what I've studied from the design i believe the only thing we will actually need to do are only the interfacing, serial i/o and AD/DA for the VCAs and other stuff that might need AD/DA (maybe total recall values?).

Also another reason to not use any of the old cards is its size. The idea is to have a compact, small and low power solution. I've been researching effortlessly for a good hardware base option for us and I think i might have found one (Raspbery Pi but much more powerful):

http://beagleboard.org/products/beaglebone%20black

This is a solution that will give us insane amount of power, lots of I/O ports, and support for stuff such as Ethernet, SD Card, HDMI, etc. This would fit perfectly for the idea I have for the software and features. If you look at the page you see that there is lots of add-ons that were made by the community and that can be connected by the I/O ports. If possible our logic to interconnect with the SSL console can be connected the same way. I wish to make a special thread about this to show the pros and cons of such system.

What your opinion on this possibility?

Cheers,

Artur


Konnektor

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Re: the e/g computer - actually a direct to disc recording system
« Reply #2 on: November 06, 2013, 09:37:56 PM »
anything can be done :)
it's just a matter of time

due to the footprint of the ribbons the box will have a certain size anyway
if there's a way to output voltages with a beagle board or sthg similar without the need of sample&hold circuits that would be awesome!
maybe we could use an lcd controller? i think these use s&h on every dot

i totally agree Marc!

I guess my main point is, let's ONLY develop what is needed and not come up with any redundant stuff.


TOTAL RECALL to DAW:
i did some packet sniffing on digidesigns pro control (ethernet) which would be ideal for pro tools
it would make already large sessions into extremely large ones, though
« Last Edit: November 06, 2013, 09:42:19 PM by Konnektor »

Artur D'Assumpção

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Re: the e/g computer - actually a direct to disc recording system
« Reply #3 on: November 06, 2013, 09:57:20 PM »
Guys these feature discussions move them to the thread I created ok ? Lets keep this specific discussion there.

http://forum.sslmixed.com/index.php?topic=446.0

Artur D'Assumpção

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Re: the e/g computer - actually a direct to disc recording system
« Reply #4 on: November 06, 2013, 10:45:20 PM »
For what I've been reading the Beagle is really powerful and the thing that caught my eye are the insane amount of GPIO it has, we're talking about 65 GPIOs we can use to interconnect our logic. It has also a bunch of 12 bit AD/DAs that we can also use. This was only common on ATMegas, but having this power on new ARM chips is insanely hot!

The GPIO ports are very low current and work at 3-3,5 VDC and is powered by 5V.

Also prices are insanely low fpr a hardware base. When compared with a commercial 10000 dollar computer for the SSL we are still left with a big margin of progression on the price side. ;)

Heres a quick feature image:





Cheer,

Artur

anything can be done :)
it's just a matter of time

due to the footprint of the ribbons the box will have a certain size anyway
if there's a way to output voltages with a beagle board or sthg similar without the need of sample&hold circuits that would be awesome!
maybe we could use an lcd controller? i think these use s&h on every dot

i totally agree Marc!

I guess my main point is, let's ONLY develop what is needed and not come up with any redundant stuff.


TOTAL RECALL to DAW:
i did some packet sniffing on digidesigns pro control (ethernet) which would be ideal for pro tools
it would make already large sessions into extremely large ones, though
« Last Edit: November 06, 2013, 10:48:41 PM by Artur D'Assumpção »

Artur D'Assumpção

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Re: the e/g computer - actually a direct to disc recording system
« Reply #5 on: November 07, 2013, 01:53:14 PM »
Refer to the following thread to discuss about the hardware platform for the development: http://forum.sslmixed.com/index.php?topic=449.0