Today I got a fully built replica A4091 Zorro 3 SCSI card delivered. The A4091 was a SCSI 2 controller for the Zorro 3 slot, it was made by Commodore. This is a reverse enginered version that you can find prebuilt on the internet or build yourself. Find out more about the original C= 4091 card here and the new replica A4091 SCSI card here.
I watched the presentation of this card on an Amiwest stream a couple of years ago so its exciting to have the real card in my hands.
Advantages of SCSI in an Amiga
The advantage of using a SCSI harddrive and a A4091 in a Zorro 3 Amiga is that it will have faster transfer speeds than IDE. SCSI is also less heavy on the system as the card has its own brain to process file transfers taking up less CPU time than IDE. This is good as Amiga is limited in CPU power (at least with a real CPU).
Zorro 3 only!
This card only works on the Zorro 3 slot. That is good news since it means better performance than a Zorro 2 card/slot. But it also means it will only work on the A4000(T) and the A3000(T). The Amiga 3000 already has SCSI on the motherboard, but if that does not work well, this card could be the solution.
Hardware setup
This card will probably end up in my A4000TX or in my A4000D. The A4000T already has SCSI2 and is basically the A4091 card implemented on the motherboard (well, the main chip is the same). As my main systems already got 060s, graphics cards and plenty of memory this is a welcome addition in squeezing out the last performance before I go into the world of PiStorms.
I will run a ZuluSCSI card on mine as I have banished mechanical harddrives from all my computers. The ZuluSCSI can emulate multiple harddrives (and CDs) stored as files on an SD card.
Purple Amiga A4091 SCSI 2 card
And I actually lied a little when I said that it was exciting to finally have the card in my hands as I already built a purple A4091 SCSI 2 card last year.
Here are some new Amiga PCBs for some new projects I got this week:
GottaGoFaZt3r memory card (will do the 256 MB version and probably a second card).
PiStorm16 x 2
Prometheus clone
MpegIt for the Prelude Amiga sound card
Prelude sound card PCB (not in the picture)
I also have two Amiga graphics cards in my todo list:
GBAPII++ graphics card
Mini GBAPII++ graphics card
And lets not forget the ReAmiga 3000 PCB I got late this week too! I have had a broken Amiga 3000D motherboard in my stash for years so finally I will be able to shake some life into it again!
So lets just say a massive BOM will be ordered soon!
The ZZ9000AX Amiga sound card for the ZZ9000 graphics card
There is a sound card for the ZZ9000 Amiga graphics card called the ZZ9000AX. It is a small soundcard that is attached directly to the ZZ9000 Amiga Zorro slot graphics card.
I had some problems with the ZZ9000AX
Keep in mind that I am running the card on an unofficial Amiga motherboard (A4000TX). So the reason for me having problems might be because of that and not the fault of the soundcard.
I got A ZZ9000AX last year but had massive problems getting it running well. The ZZ9000AX seemed to be picking up noise off the bus and had a disturbingly loud background buzz that never stopped. Paula sound is passed through the ZZ9000AX from the ZZ9000 through a three wire cable.
When Paula output was passed through the ZZ9000AX it just sounded horrible. Sometimes distorted, sometimes just totally blurred in background noise. Sound output so far from the regular crystal clear Amiga sound output I was used to.
I contacted MNT about the problem and I was sent a replacement card from MNT – But it did not fix the problems, just introduced different sounding problems. As I was running it in my A4000TX which is a non standard Amiga model (with no public schematics) it is difficult to say where the problem lies. There might be some kind of difference between an A4000D CR (that the A4000TX is based on) and an A4000TX that introduces these problems into the audio output.
I am going to test my card on my other Zorro 3 machines in the future to find out if it is the fault of the A4000TX or not (will update this text). But the card was sadly unusable for me in my A4000TX.
Finding a solution
ZZ9000AX with external to internal cable
Playing around with the card I noticed that if I removed the three wire cable that connected Paula audio output into the ZZ9000AX (you can see it attached to the card above) the card was beautifully silent, no bus noise, no irritating static and no weird noises. Playing MP3s worked fine as they where being played on the ZZ9000AX and not on the Paula.
The A4000TX is a clone of the Amiga 4000CR and shares the same features, one which is a input header on the motherboard originally meant for CD audo to be merged with Paula output.
So I got an idea to remove the three cable wire that connects the ZZ9000AX to the ZZ9000 altogether and route the output from the ZZ9000AX into the input header on the motherboard instead.
That means that the output of the soundcard was mixed into the sound jack of the A4000TX.
Cable in detail, it is just a simple cable, nothing special to be honest
I created this little cable just to prove if it could work. I will make a nicer looking cable in the future. The A4000D and the A4000TX (that is based on the A4000D CR) has a audio in input on the motherboard, likely for CD-ROM input or for AV purposes.
It is connected to line in on the A4000TX motherboard so it gets mixed into the output for the sound socket.
You can see the cable connected to the audio input header on the image above. It is a messy setup, but the system is in a state of work in progress at the moment.
The cable is just a nasty quick hack, I will do something better here in the future
Here is the backside of the A4000TX and how I route the cables to the internal audio input. No doubt I will create a more neat solution in the future, but for now this will do.
Does the fix work?
Yes it does, I have configured AmigaAMP to use the MHI drivers for MP3 playback. Both MHI and AHI works fine. There is no bus noise and no ringing noises in the background. The sound output is dead silent when the Amiga is not producing any sound – Just as it was meant to be and how I expect it to be. And best of all, playing modules in an module player sounds crystal clear. Playing MP3s on my Amiga sounds just as they do on my PC now!
There is just one little problem
There is one disadvantage of this setup, and that is that the audio input header on the Amiga 4000 motherboard lowers the noise a bit compared to Paula output. I have not found a fix for this yet. One fix would be to run a separate mixer that mixes ZZ9000AX and Paula audio into one, however that just sounds too messy, so I will stick with this solution and just increase the audio level a bit whenever I run something on the ZZ9000AX card.
