How to make an STDM cable for cheap

Tips and advice for getting the most from Scope. No questions here please.

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moxi
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Post by moxi »

You're right, I hope none will follow me in such thing, I agree that it's really hard to justify (the environment things was rather kidding from my side)..

but how to say that I'm now looking at each buck spend, when you see that some years ago Iv'e spend with my S&B org' so many dollarz in gears..

maybe it's the price to go on such a long time Non-commercial and keep all services as free as they was when my personnal bank account was more filled...

I can say you that musicians and multimedia/performers artists really don't care about the crappy looking of my stdm connections when they record or prepare their songs/performance for only the price of a beer...

and I've to say that the buy of a third board was never envisaged from my side, this pretty Luna is arrived here as a donation from a guy that probably don't feel me so stupid, so..

:wink:

....and I will never send my beloved boards back to second hand market to replace my SC stuff by shitty cracked VST, be sure of that!
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Neutron
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Post by Neutron »

I finally did it.

You can make them exactly for your situation.

The middle one has to be slightly modified with a sharp knife and/or dremel if you want the cable to come out straight, the connectors are supposed to be for "ends" not in the middle of the cable.

The spacing between PCI slots is 0.8 inches, the connectors are 0.4 inches wide, so if you do like this you can use one of the connectors as a guide.

gap between cards_____space between edges of connectors
0 __________________0.4"
1 __________________1.2"
2 __________________2.0"
3 __________________2.8"

looks nice with black cable :) its just asus floppy cable reduced to 20 (take of 14 they are 34 conductors). I stopped using floppies ages ago but they keep giving me those :)

and they STAY ON TIGHT!
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stdm.jpg
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Tau
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Post by Tau »

You guys are inspiring!

Today, I installed 3 cards on the same computer, only two were in a magma chassis with a PCI interface, and the other was on the PCI slot of the Motherboard. How did i do this? A home made 1 meter long STDM cable connecting the first connectors of each card!

This is great!

The flat cable comes out of the Magma through the open slot (it has 3) in the back, and into an open slot on the back of desktop, so everything is shut. Right now, both cases have to be close to each other, and when I want to take the Magma away, I have to disconnect the stdm from inside the case, but I want to develop this idea further... there must be a way to break a flat cable and insert some sort of plug, so it can be extendable... Like IDE have male and female, but of course the male of the STDM is the connector ot he board...

Something to think about, but for now, I'm HappY!!! :) I have almost as much bw as if I was using the 3 PCI slots (14 MVs instead of 17), but now, when I want to, I can just take 30 of those DSPs out, go play somewhere, and still have a working studio at home, with everything properly connected!

It's still better than pulling the cards back and forth...

Thank you all for this great piece of information! :)

Now, what would happen if I installed a second (fourth) card inside the DAW?



..... (does anybody know? Does it take an STDM cable with 4 plugs?) .....

I'd love to know that!

Cheerz!

T
Attachments
2 PROs in the Magma, 1 6 inside the case. This was just a first experience, the cable now goes from the back of each case :) I made 2 cables, but the other one doesn't work...
2 PROs in the Magma, 1 6 inside the case. This was just a first experience, the cable now goes from the back of each case :) I made 2 cables, but the other one doesn't work...
IM000298.jpg (356.69 KiB) Viewed 13915 times
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Neutron
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Post by Neutron »

so you get reliable function of scope with

a: 2 meter long STDM cable and
b: cards on separate PCI buses?

i never would have thought it possible, 8)
MD69
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Post by MD69 »

Hi Tau,

You should REALLY discuss this with ralph. There is some risk at power up to break your cards (transcient reverse voltages etc...).

cheers
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Tau
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Post by Tau »

Neutron: yes to both, but only 1 meter cable :)

MD69: Well, thanks for letting me know! I have contacted Sonic Core on this, but didn't get an answer... It does seem too good to be true, but it 's working well so far... How big a risk do you think it is?
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Post by MD69 »

Quite difficult without schematics, but there is good chance that the S/TDM bus is not protected against reverse polarity. So it will depend on which power supply lead the race!

maybe someone with a deeper knowledge on scope hardware!?

cheers
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Neutron
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Post by Neutron »

i dont think there are any power lines , just data, and they are designed to be left open as well (no cable connected) i think that if a card was accepting data before it was turned on it would not matter,
as long as both the PC and magma are grounded to the same electrical circuit.

even old school crappy cmos ICs could take a logic 1 with the power off.

WHat i WOULD do is get rid of the extra cable after the last connectors, especially that long bit.
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Tau
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Post by Tau »

Neutron wrote: WHat i WOULD do is get rid of the extra cable after the last connectors, especially that long bit.
Yes, well spotted, and it's gone now. My idea was to leave a little bit for a hypothetical 4th connector, but then i realised that the plugs actually open up, and the upper and lower parts separate from each other completely, so I can put the ends first and then any in the middle... live and learn.

So if I understand correctly from Neutron's words, STDM is a data connection, and should be relatively safe to use in such a twisted way. I certainly hope so, as this is the el dorado of scope, as I always wanted it to be!

I always power up the chassis before the main pc, so it can be recognized by XP. is there any particular thing I can do to reduce the risks of electrical damage?

I can still get some flatcable here, but not much, as the only electronics shop that still stocks it has only about 10 meters left. What I'd like is a sort of plug that can be inserted into the STDM cable and create an extension, so I didn't have to open the case whenever I wanted to change configuration. If that can be done, and this doesn't blow up, I'm ready to re-arrange my studio.

On the other hand, if it is that risky... wouldn't like to lose 3 cards at once.... I am planning on using the chassis with a 12v DC/DC PSU with all sorts of surge, over and undervoltage protection - will that be of help, or make things worse?

I'm in doubt, but I am excited... Any ideas on "more than 3 cards"?


T
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bill3107
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Post by bill3107 »

just amazing !!!! that could even be a kind of anouncement ? :wink: :lol: ...
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Tau
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Post by Tau »

OK, I have had an idea that's simple, although I'm not sure it'll work. Before I take this further, I have to do some more tests and see if this is really as stable as it seems. But please, read on and tell me what you think:

The objective is to make 2 STDM connections, between the 2x15 DSPs on the chassis and 1x6 DSP on the main CPU, in such a way that:
- it's not necessary to open any of the cases when plugging / unplugging (external connection)
- it's not necessary to remove any card or any STDM connector from the cards at any time (permanent solution)
- The connection is solid but easily removable.

Here's my idea: to make a special STDM cable, using 2 strips of 20 connector flat ribbon cable, 4 regular STDM connectors, and a 40 connector IDC male plug (this is like the IDE connector on older hardrives) -

http://www.connectworld.net/cgi-bin/iec/ID40M .

This male plug can join both strips (20+20 connectors= 40 pins), and be placed outside the chasis. If the cables are joined in the middle (with the regular STDM plugs on the edges) we would have the added benefit of keeping both 15 DSPs connected to the outer plugs even when the other card is not connected.

Then, we would need another special cable, but even simpler: another 40 pin plug connected to 2 20 contact ribbons, one for each STDM connector, and this plugs into the 3rd board.

So now we have: 2 cards on the chassis, connected via STDM internally, and with an open middle plug outside of the box; and one card inside the DAW, with 2 STDM connectors linked to an open plug outside the box.

To connect the two, we simply have to use a round IDE cable! This will connect all 40 pins, and put the 6 DSP in the middle of the STDM bus. The cable should really be as short as possible, but it's easily available and much nicer than 2 strips of flatcable...

Things to watch out: the number of the pins has to be well noted, so that pin 1 is the same in all cards, and STDM 1 is the same as well. IDE plugs are assymetrical, so there's no risk of accidentally reversing it. Also, the cables will have to be folded 90 degrees inside the chassis - that should be done carefully.

Alternatively, one could use SCSI cables, that have 50 pins (I think).

So, what do you think? It seems to make sense, but I might be overlooking something, and I would really appreciate your input.

I'm also starting to get a flashback, as I can't seem to find stores in europe that sell these sort of parts... It's quite complicated to read through those part catalogues, the link above was the only one I could find, but if I go ordering from the states it's going to get expensive... So if you know of any, and can direct me...

Well, let me know your ideas!

Cheers,

T

EDIT: In fact, I found that IDE cables and plugs cannot be used, because they have a "blank" pin that reduces the number of connections to 39... But there are 40 pin IDC connectors that could be used in the manner I said above, only flatcable will have to be used for the connection instead of the round IDE cable. Not so good looking, but it's supposed to stay on th shelf, anyway...
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garyb
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Re: How to make an STDM cable for cheap

Post by garyb »

a had another client who did the same thing with a magma...
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Neutron
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Re: How to make an STDM cable for cheap

Post by Neutron »

garyb wrote:a had another client who did the same thing with a magma...
do the other cards (in the magma) really need anything but PCI power? maybe the main card reports and uses all the other DSP attached to it via STDM

it would be very easy to make a PCI card holder board that just supplied the power and the STDM connected to the main card. it could be made from a PCI riser and a couple of voltage regulators, powered from the PC power supply.

I have a spare pulsar1 card i took the IO plate from i might have to test in the name of planetz :)
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Tau
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Re: How to make an STDM cable for cheap

Post by Tau »

Neutron, do you mean without the magma PCI card? That'd be awesome, since I already sold a Magma set with the PCI interface...

maybe I was too Xcited....
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garyb
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Re: How to make an STDM cable for cheap

Post by garyb »

bump.

it would be a shame to lose this one.
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dante
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Re: How to make an STDM cable for cheap

Post by dante »

True. I should ScopeRise it I spose.
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Tau
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Re: How to make an STDM cable for cheap

Post by Tau »

The things I did before XITE :lol:

The setup on the picture was working very well, and I did source the parts for the extended STDM connectors. I didn't get to build them, though, since I lost one of the 15 DSP cards shortly after. At the time, they were all together inside the main computer, and that's why I think that this little experiment wasn't what caused it... But repeatedly installing and removing cards between the Magma and the MoBo might have had an effect, and that was exactly what I was trying to prevent with the 2+1 solution.

Much easier now with the XITE :P

I'm still curious about if it would work without the Magma card (power only to the external cards via PCI)...

T
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astroman
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Re: How to make an STDM cable for cheap

Post by astroman »

Imho it's not enough to just power the cards, seems you have to 'feed' them a basic Scope system at least.
I've tried that once (for curiosity) and the 2nd card (or rather it's DSPs) wasn't recognized.
(simply put a mini PC next to the Scope box with a card plugged in, but left out the OS disk)

cheers, Tom
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Tau
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Re: How to make an STDM cable for cheap

Post by Tau »

Thanks for trying it out, Tom! If it worked, it would possible to have 3 cards in a single PCI slot, but it seems that you need at least 2 slots and a Magma...
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Re:

Post by Immanuel »

Neutron wrote:I finally did it.

You can make them exactly for your situation.

The middle one has to be slightly modified with a sharp knife and/or dremel if you want the cable to come out straight, the connectors are supposed to be for "ends" not in the middle of the cable.

The spacing between PCI slots is 0.8 inches, the connectors are 0.4 inches wide, so if you do like this you can use one of the connectors as a guide.

gap between cards_____space between edges of connectors
0 __________________0.4"
1 __________________1.2"
2 __________________2.0"
3 __________________2.8"

looks nice with black cable :) its just asus floppy cable reduced to 20 (take of 14 they are 34 conductors). I stopped using floppies ages ago but they keep giving me those :)

and they STAY ON TIGHT!
Can anyone spot what kind of blue connectors are used in this set-up?
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