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Captain Egotist · Feb 11, 2005, 02:50 PM

I have a quicksilver and at the moment I have twin 17" apple ACD displays.... how could I run both of them from the same machine? Two video cards? ???

Would I need a bigger power supply?

Thanks!

- Rob

frozenstudios · Feb 11, 2005, 04:44 PM

There is a box that changes the signal to a VGA and lets you run dual ADC monitors, this also adds the power in to the second display, heres the link:

http://www.barefeats.com/vga2adc.html

chris

spiky_dog · Feb 11, 2005, 08:11 PM

Originally posted by Captain Egotist:
I have a quicksilver and at the moment I have twin 17" apple ACD displays.... how could I run both of them from the same machine? Two video cards? ???

Would I need a bigger power supply?

Thanks!

- Rob

radeon 9000 with one adc, one dvi output + dvi->adc (not other way around! $100 vs. $30 sadly) converter

Big Mac · Feb 11, 2005, 08:59 PM

Originally posted by Captain Egotist:
I have a quicksilver and at the moment I have twin 17" apple ACD displays.... how could I run both of them from the same machine? Two video cards? ???

Would I need a bigger power supply?

Thanks!

- Rob

The ATi 9800 and x800 both have dual ADC, at least in their OEM versions.

Detrius · Feb 11, 2005, 09:10 PM

I have never seen a dual ADC. I've seen ADC+DVI and dual DVI. If there were dual ADC cards, I would need a new adapter at the bench.

Big Mac · Feb 12, 2005, 02:47 PM

Oops, I was almost certain that my 9800 has dual ADC ports. They look pretty darn identical. Sorry about that.

chris v · Feb 12, 2005, 03:28 PM

Originally posted by Captain Egotist:
I have a quicksilver and at the moment I have twin 17" apple ACD displays.... how could I run both of them from the same machine? Two video cards? ???

Would I need a bigger power supply?

Thanks!

- Rob

So. My answer over there wasn't good enough for ya, huh? Sheesh. Nooooo gratitude.

Rob, got to store.apple.com and search for ADC DVI. It'll pop up at the very top of the list.

Captain Egotist · Feb 12, 2005, 06:22 PM

So basically I'd have to purchase some $100 dohickey in order to hook up the 2nd one.

That's really freakin lame.

Couldn't I just install a PCI video card in one of the expansion slots?

osxisfun · Feb 12, 2005, 07:04 PM

yes.

Link · Feb 12, 2005, 07:13 PM

The ADC plug is DVI-I + power + USB, you can't just add a PCI card because the AGP port on some g4s/g5s has a special header for ADC.

The DVI "adaptor" is simply a power supply.

Cadaver · Feb 12, 2005, 10:29 PM

Originally posted by Captain Egotist:
So basically I'd have to purchase some $100 dohickey in order to hook up the 2nd one.

That's really freakin lame.

Couldn't I just install a PCI video card in one of the expansion slots?

No.

A second video card will still require a DVI-to-ADC adapter ($100) to drive an older Apple Studio/Cinema Display. And, the second (PCI-based) card wont be Quartz Extreme accelerated, at least not without a hack to the OS (easy to apply but may decrease performance of other PCI cards in your system).

People are forgetting that the (older) Apple displays do not have their own power supplies. Something must provide power for them. This is a well known issue, and there have been external DVI-to-ADC converters (basically a box that simply passes the DVI video signal untouched, but adds a 28V line to power the display) since Apple first released the Studio/Cinema Displays with the Apple Display Connector (ADC). A company called Dr. Bott was first; Apple's own box came later.

Apple designed the ADC to power only one display. Remember, two displays were not nearly as common place back then as they are now. The first video cards of Apple's to even have an ADC connector was the ATI Rage 128 - which did not drive two displays. Even the first Radeon cards Apple used didn't drive two displays; Apple's first card to support multiple displays was the nVidia GeForce 2MX Twin View, which IIRC was included with certain Quicksilver G4 models.

In any case, to drive two displays, the power supply Apple designed in to their systems would have been more expensive - where most users wouldn't have taken advantage of.

This, I think, is one of the major reasons Apple has since discontinued the ADC port on their displays in favor of displays with their own power supplies and standard DVI interfaces. Apple still includes a single ADC port on their PowerMacs to support the legacy ADC-based displays out there (so as not to force everyone to buy a $100 box).

The ADC system received a lot of criticism for several reasons, one of which is the added expense of a $100 adapter (to provide the power) in two-display systems. This lead many to choose non-Apple displays for their systems, so they didn't have to spend the extra hundred just to connect a second display.

The need for a $100 adapter to power display number two is a well-documented issue with the ADC-based Apple displays. Apple even used to bundle second displays with the adapter on their build-to-order configuration page.

If you really want two displays, your options are to either pony-up for the DVI-to-ADC adapter or replace the second Apple Studio Display with a third party display (or a new Apple brushed aluminum (non-ADC) display).

Cadaver · Feb 12, 2005, 10:36 PM

Originally posted by Big Mac:
The ATi 9800 and x800 both have dual ADC, at least in their OEM versions.

No Apple card has ever had dual ADC. One ADC, one DVI. They look similar, but the ADC connector is longer and oval-shaped.

And, BTW, there are no x800 OEM cards. The Radeon x800 XT is an ATI retail card only; it is not offered by Apple as an OEM card. But it also has one ADC and one DVI port.

The current Apple OEM nVidia cards, FYI, have no ADC connectors. Two DVI only. These cards do still make use of the ADC power connector on the G5 motherboard as a source of additional power since these cards are so power-hungry.

Oh, and any ADC port can be 'converted' to a standard DVI or VGA port by a $30 adapter.

Cadaver · Feb 12, 2005, 10:45 PM

Originally posted by frozenstudios:
There is a box that changes the signal to a VGA and lets you run dual ADC monitors, this also adds the power in to the second display, heres the link:

http://www.barefeats.com/vga2adc.html

chris

This box converts an analog VGA signal into a digital ADC signal. Its for people with older VGA-only PowerBooks, PowerMacs and PCs who really want to use an Apple ADC Studio or Cinema Display.

It is not what's needed here unless the original poster (the Quicksilver owner) has an old dual-head video card that has one ADC port and one VGA port (and I think the only card that has such a connector config is the first GeForce 2MX TwinView).

This Gefen device is also about $300. It would be cheaper to buy a new AGP video card with two digital video ports and an Apple DVI-to-ADC connector than it would to buy this one VGA-to-ADC box.

Captain Egotist · Feb 13, 2005, 10:47 AM

Originally posted by Cadaver:
If you really want two displays, your options are to either pony-up for the DVI-to-ADC adapter or replace the second Apple Studio Display with a third party display (or a new Apple brushed aluminum (non-ADC) display).

That sucks. The twin apple LCDs look so nice when they match... I wouldn't want to have mismatched monitors.