QS dual 1ghz processor in DA G4?

It's certainly worth trying. I was wandering through links last night on the same subject, and did see one reference that only the 733 CPU would work, but then saw that directly contradicted. :/

The PSUs are different by one wire, as outlined here. Wouldn't take much to change that one wire, but do you really want to introduce a potentially very bad PSU to your working DA?

If you follow links from Alk's thread, you could adapt an ATX PSU to try on the MDD G4, and you'll also see notes on the 12V lug connection for trying the MDD CPU in the DA system.

I am currently running a QS 867MHz cpu in a DA MLB and using the DA power supply. I did have to use the 12Volt modifcation on the 4th lug in order for the CPU to power up. It works with out issues and the cpu speed is correct as both the DA and QS have the 133 buss.

In reading your post on the QS my guess would be a bad power supply that took out the video card/MLB when it went. However the CPU may still be good. All you can do is try it. It will either boot or it won't boot or it may boot up and then freeze up the system.

I may be wrong here but I believe that the DA and up MLB's will support Dual cpu's with out issues. All you can do is try

Yeah, maybe I should try to get or make a PSU for the Quicksilver instead of trying the double gig in the DA. Lots more to gain that way, and too much to risk the other way. Here's another page with QS, MDD, and DA PSU pinouts:
http://www.xlr8yourmac.com/tips/MDD_ps_mods/MDD_PS_Mods.html

And here's for the Sawtooth and the ATX:
http://www.xlr8yourmac.com/systems/ATX_G4_AGP_conversion/G4_AGP_to_ATX_case_pg2.htm

Well, I just went back and read more carefully alk's thread that I linked to above, and this time followed the link he provided in his thread to his other thread about his MDD Power Supply Conversion and frankenmac 8600 project. At the bottom of that other thread he states emphatically that he has a QS dual 1Ghz running fine on his DA board which he put into his 8600 case and counters warnings by others about attempting the upgrade.

Still yet, I think I'm going to pursue getting a working QS PSU instead. This is an interesting link I gleaned from that thread along the ATX conversion idea: converted ATX kit for Mac DA and QS G4's
It includes an external 24v PSU for the ADC power line. Click on the pic of the ATX PSU for pics of the accessories.

Regarding a QuickSilver CPU in a Digital Audio G4, I swear up and down that it works perfectly (though you might want to work out some sort of heatsink fan - the dualie G4 is HOT). The only modification needed is to hook up a 12 V line to the 4th post on the CPU card. It's VERY easy to do. This works with cards of all speeds from 733 MHz to dual 1 GHz G4s. I've done it personally with an 800 MHz card, an 867 MHz card, a 933 MHz card, and a dual 1 GHz card.

I can probably take detailed pics if you want them.

Anybody else who calls me a liar better be prepared to take a smackdown. ;-)

Peace,
Drew

I said Quicksilver PSU's are still very pricey. I was watching this auction:
Quicksilver PSU auction
Sometimes when you think you've got a grasp on the world, something you see just blows you away. What a happy seller.

That's insane.

DA PSUs will fit in a QuickSilver, but of course they don't have the extra pins for the QuickSilver MB. I'm pretty sure you can run a QuickSilver without those extra lines (they're just 12 V lines, and I think they go to the CPU) if you do the 12 V line "hack" to apply power directly to the fourth CPU post.

MDD PSUs can also be made to work, and they are much cheaper. They aren't a drop-in replacement, though, as they are a different size and shape. A little creative casework and mounting will make it fit, though.

You can also go the ATX route. That's a little different as the ATX supplies don't put out the 28 V line for ADC display support. You can always just tie a 5 V or other line to that, though.

Peace,
Drew

Yes, you can put a Quicksilver CPU into a Digital Audio but you have to pull an additional 12 volt line from the PSU. There are details of the mod in many places. Google is your friend. That is the very nice thing about the Digital Audio, and the main reason I recommend them over all other machines in the G4 tower line is that you can use any Quicksilver CPU and aftermarket upgrades are designed to work in both. You don't have to mod the aftermarket parts, though. You won't get the 167mhz bus of the faster MDD/FW800 models, but you can get the ports that they have that the DA doesn't by way of expansion cards and the 133 mhz bus isn't exactly slow in this class. The memory is also cheaper for the QS/DA than the later models. The later models also suffer a deficiency in aftermarket upgrades for some reason, so you can crank up the speed on a QS/DA higher than the MDD/FW800. I also favor the appearance of the first several generations of G4 prior to the QS, but that's entirely down to personal taste.