Restoring the “A” to a Quadra 840AV

Regular readers of this blog will know that some time back, I acquired a Quadra 840AV, the last and the fastest of the 68040 Macs. As a product, the Quadra 840AV was notable in many regards. Clocking in at 40 MHz, it was the fastest 68K-based Mac that Apple would produce. The primary 68040 was augmented by a 66 MHz DSP coprocessor, designed to provide the 840AV with a range of audio and visual capabilities (hence the “AV” designation) that were largely offloaded from the main processor. Also, the Quadra 840AV featured the then incredibly innovative feature of interleaved RAM. Taken as a package (40 MHz CPU, 66 MHz DSP and interleaved RAM), the 840AV was simply a screamer in its day.

Quadra 840AV 02

The 840AV, and its lesser sibling the 660AV, while unique for a variety of technical reasons, were especially touted for their A/V capabilities. You can imagine my distress then, when my 840AV’s speaker started crackling one evening, and then went ominously and completely silent. Something on the motherboard had fried, popped or otherwise gone into permanent retirement, and the 840AV had suddenly dropped the “A” from its moniker and become simply an “840V”!

Not being a particularly handy electronics technician type, I quickly decided that my likelihood of repairing whatever was wrong on the motherboard was infinitesimally small. However, being resourceful and persistent, and recognizing that the 840AV had three perfectly good NuBus expansion slots, I sought out a alternate sound card for the machine on eBay. If you can’t go through a problem, go around it! I was fortunate to quickly happen upon a Digidesign AudioMedia II card, bid on it and win.

DigiDesign AudioMedia II

Drivers for the AudioMedia II seemed easy enough – I readily found the Digidesign software archives ( and downloaded the right stuff. It is amazing that it is all still available to this day, more than 20 years later, but it all still is. To this point, the story has been largely recounted in earlier blog posts on the topic. So what happened? Read on…

I inserted the card into the machine, installed the drivers into the Extensions folder and restarted the venerable Quadra, full of hope that I had restored the (now) 840V back to its full 840AV designation. Alas, this was not to be the case. There was no audible change at all, and despite my best efforts with various versions of the drivers and various re-installs, the new AudioMedia II could not be enticed to make even a peep.

After a time, I decided that perhaps the card was bad, or perhaps I had the wrong drivers… or perhaps something else entirely unknown was wrong. I resolved myself to watching eBay again, and waiting either for an 840AV motherboard to come along, solving the original problem, or for a new AudioMedia II, replete with the original drivers, to come along, perhaps resolving the current problem.

Since then, no Quadra 840AV motherboards have shown up on eBay. Lots of AudioMedia II cards HAVE shown up, but none with the original drivers. In all this time, the Quadra “840V” has remained stubbornly silent. I am nothing if not persistent, and so from time to time, I would return to this matter, making renewed efforts, always with no success. Then, just recently, an “aha!” moment.


Documentation on the Digidesign software archive is minimal, and seemed to suggest that the provided sound drivers were all that was needed. Slightly more documentation, but still quite sketchy, was provided within the driver’s StuffIt archive. One evening, rereading that documentation for the nth time, I was struck by the continual mention of ProTools and their DigiSystem INIT. Hmmm… DigiSystem INIT… Perhaps I was still missing a key piece of software?

I went hunting for the lightly referenced INIT and found it at For an 840AV running Mac OS 8.1 (as mine does), the right version seemed to be 2.96 (near the bottom of the page) and so I downloaded that one.

Yesterday, I installed the INIT into the “840V”’s extensions folder, alongside the already installed AudioMedia II sound drivers, and with fingers and toes crossed, restarted the Quadra. Sigh… again I was greeted with roaring silence. The Monitors and Sound control panel did not show any alternate sound input or output sources, and any control panel or application that should have created sound remained oh so very quiet.

Then I remembered that for whatever reason, it was only possible to select the AudioMedia II as a sound input and/or output via the long dead and gone “Sound” control panel – it could not be done via the Monitors and Sound control panel that shipped with Mac OS 8.1. For this reason, the DigiDesign audio driver StuffIt archive provided a copy of this older control panel. I found it and fired it up. Eureka! I was greeted by this happy sight in each of its Input, Output and Volume selections, finally showing DigiDesign (the AudioMedia II) as an available sound input and output:

Sound Control Panel With DigiDesign

Nearly trembling with anticipation, I fired up SimpleSound and made a new selection… Sound! Glorious Sound! It made a noise! I tested all sorts of sound applications after this and THEY ALL WORKED! After such a long struggle, this was serious gratification!

So, for those of you looking to make use of a DigiDesign AudioMedia II NuBus sound card (which I have read repeatedly is one of the best sound cards ever released for 68K Macs) in a Quadra 840AV running Mac OS 8.1, here is the recipe for success (and I bet it works for other versions of Mac OS as well – I simply haven’t tested any but Mac OS 8.1):

1/ Get version 1.4.1 of the AudioMedia II sound drivers at

2/ Get version 2.96 of the DigiSystemINIT at

3/ Extract the Sound Control Panel that is included with the drivers and copy it to your Control Panels folder. Personally, I left the Monitors and Sound control panel there, and put the Sound control panel into a separate folder called Control Panels (disabled), but you can do as you see fit.

4/ Restart the Quadra.

5/ Start the Sound control panel and select the DigiDesign entry for each of Sound Input and Sound Output. Adjust the volume to your liking.

6/ Enjoy!

For me, this has restored sound to my Quadra “840V”, returning it to full 840AV status. I hope that it may be equally successful for you.


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