• Registered: 2009-04-16
  • Posts: 24

Topic: Dummy housing for expansion boards

Looking at regular pc cases, the rear expansion slots (often no more than 7) struggle to accomodate a scheme of multiple analog i/0 expansion boards, especially with a GPU blocking at least 2 slots.
Cramming all boards into the remaining real estate causes thermal issues, so I am looking at housing the expansions externally (e.g. AI4S/192 AIO, AEB4-I  etc). Cable length calls for vicinity placing (I would drill holes if need be), I was going to manufacture a case accomodating the dummy slot connectors holding the expansion boards in place, such cases are being marketed but they are expensive due to (I assume) connectivity to the mainboard, something I wouldn't be needing.
Is there a template/idea/product I overlooked, for this purpose? thanks.

  • From: UK
  • Registered: 2018-08-18
  • Posts: 41

Re: Dummy housing for expansion boards

Does your machine have 5.25" drive bays ?

If so you can mount the expansion boards in 5.25" blanking panels cut out to fit board.
Including in the original packaging for an AI4S I bought I seem to recall a paper template to aid doing this.

  • Registered: 2009-04-16
  • Posts: 24

Re: Dummy housing for expansion boards

thanks for your idea, I will ponder that. I would prefer to have it all "sticking out in the back", rather than connect audio cables front and rear.
I see that larger pc housings now sport vertical slots in addition to the horizontal ones, in the back. That solves the rear connectivity, but the internal board fixation issue is still open.

  • Registered: 2009-04-16
  • Posts: 24

Re: Dummy housing for expansion boards

So I am now investigating cases that offer rear expanson openings aplenty, including additional vertical slot openings (where you would usually  mount a GPU with a riser cable extension).
Knowing that the amount of mainboard slots is the limitation (memo- I am planning to add 4 exp i/o exp cards to my AIO, most MB will offer 3 at the most once the large GPU is installed), is it reasonable to discount that limitation altogether, just stick the exp cards into the available rear openings regardless of corresponding MB fixation, and just replace that mechanical MB support through gimmicks like upHere support stands.
Anybody else come up with ingenious/working solutions for stacking multiple exp boards into their PC housing, overcoming the said limitations?

  • cyrano
  • DAW Mastermind
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  • From: Belgium
  • Registered: 2015-04-28
  • Posts: 695

Re: Dummy housing for expansion boards

It might be cheaper to buy a XXL server case and expand PCIe internally.

Less chance of interference, more choice in case layout.

Add-on expansion chassis are expensive because it's a tiny market, compared to regular PC cases. You can find PCIe expansion boards with cables on Chinese sites for very little money. You'd need to experiment a bit, of course. The first one you try might not work for your application.

I used to build systems and anything as high-bandwidth as PCIe needs attention. That's why I'd want to keep that internal. Maybe I remember SCSI problems with external cases too well? big_smile

MB Pro - 2 X FireFace 400, FF800 & DigiFace USB
ADAT gear: Korg, Behri, Fostex, Alesis...

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6 Reply by delgado (edited by delgado 2020-07-25 12:41:57)

  • Registered: 2009-04-16
  • Posts: 24

Re: Dummy housing for expansion boards

but the cards I want to mount do not require any internal connectivity towards the mainboard, they just use up slots mechanically... or am I misunderstanding you?

All i need is a cable connection between the expansion boards and the mother card (AIO), which makes the solution of mounting the expansions in the the same case as the AIO preferable.

edit- upon re-reading, I see that seems to be just what you suggest. So it still boils down to how to fixate the free-floating expansion cards, if I am going to mount them to the vertical slots. Maybe they don't even require additional fixation, once they are screwed to the slots.

  • cyrano
  • DAW Mastermind
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  • From: Belgium
  • Registered: 2015-04-28
  • Posts: 695

Re: Dummy housing for expansion boards

It's just a thought...

I once went looking for 9,5" racks. The Fireface 400 is 9,5". Half rack.

Surprisingly, 9,5" racks exist. But there's maybe two manufacturers, so they're not exactly cheap.

I ended up with standard 19" racks...

MB Pro - 2 X FireFace 400, FF800 & DigiFace USB
ADAT gear: Korg, Behri, Fostex, Alesis...

cyrano's Website

  • Registered: 2009-04-16
  • Posts: 24

Re: Dummy housing for expansion boards

Thanks again for your input. I believe there is still a misunderstanding here, and that is probably due to my erroneous use of the term "fixate" when really I just meant "fasten".
So I 'll reiterate my situation, if you bear with me:

I will be using an AIO PCIe card on a mainboard that obviously also houses the GPU, but otherwise has slots to spare. Now depending on the mainboard I'll get, and the vertical distribution of the slots, I will be left with 2-3 empty usable slots (GPU will hide at least one empty slot, due to its height). Bandwith and even protocol of thoses slots is immaterial, as they will only serve to mechanically *fasten" the add-on I/O cards I have for the AIO (4 in total). Again, these add-on cards are connected to the AIO by different cables, but they do not talk to the mainboard, they just sit in those slots so the analog audio cabling running from those add-on cards can be done through the rear of the PC case.

Since I probably won't have enough usable slots on the mainboard, I was looking at using the additional vertical slots some PC cases offer, in the rear. The problem here is that there are obviously no mainboard slots to fasten those vertically installed add-on cards into, so they would be "free-floating", save for the tiny screw that presses the cards metal bracket to the PC housing.

Apologies for the long-winded and possibly redundant clarification.