Prelude 1200 - heavy distortion (and crash) above 27420Hz

[rvo_nl]

Hi there.

 I have just acquired a Prelude 1200 (clockport) and, while the device seems to output fine now for the most part, I have some trouble getting it to play in full quality.
 
Im trying to get AmigaAmp and Digibooster to play but as soon as I go above 27420hz frequency, the sound is distorted (very high pitched garbage / hissing) and the machine crashes soon after.

 I am currently using:
 
- OS3.9 (bb2)
- AHI 4.18 (Aminet)
- Prelude Install 2.0 (ACT website)
- Prelude.library 5.3 (ACT website)
 
I've set up Unit 0 (which is used in AmigaAmp) in AHI as Prelude: HiFi 16 bit stereo++ realtime, and this is the same mode I have chosen to use in Digibooster. BTW I use the WarpUp engine in AmigaAmp.
 
Like I said, playback at 27420hz works fine. But this card can do better, right?
 
Things I've tried:
 
- disable MCP
- enable 56KHZAUDIO tooltype in CGX4
 
Anything else I should look into?

[rvo_nl]

thanks for clarifying. yes, that is what I meant, ofcourse..

[rvo_nl]

Finally I meet someone with a prelude 1200!! I've been looking for a long time. Good to 'meet' you..
 
 Anyway. As my sig states, I have a 060/50 too, so that is not the issue. Too many channels? Nah, dont think so either. It happens with AmigaAmp too and the mp3 decoding is handled by the ppc processor, so..
 
 Could you perhaps do a version on the prelude.library and also on devs:ahi.device? curious to know how you have installed your device.

With Prelude Tape Player, do you mean Play16 by any chance? I havent tried that. The program PrlTest does play a very short sample, but that is too short to tell in what frequency it plays.

[rvo_nl]

awesome, thanks so much for your help. I will try out what you said tomorrow. I really hope I can get this thing working. I believe this will be my Final Expansion. But, you never know.

[rvo_nl]

I dont see why that is funny! But I dont care, because you have a Prelude 1200.

[rvo_nl]

really? you have installed AHI 6? Well, perhaps that makes sense. I was always against AHI 6 because of the beta state and the fact that there was no normal Paula device included, I never figured out why.. but now that Im going to use AHI only for Prelude playback, perhaps I shouldnt even care. Do you remember if it was a lot of trouble installing it? It has to be done manually, right?

And, well.. I dont have much room for expansion left in my machine. And I'm not going to add zorro or pci either. So I guess Im 'done'

[rvo_nl]

I dont know I dont know much about AHI 6. I know there are versions for many platforms, like morphos, ppc, 68k etc. I guess I just have to try it out. Whenever I find the time to do so, I will post the results. Thanks so far!

[rvo_nl]

27 KHz at 16-bit resolution means a transfer speed of at least 54 Kbps. Can the clock port handle that much when the CPU needs cycles to feed it with data?

 Especially with my clock port extension cable in place, that is something I am sersiously questioning now, too. I am in contact with ACT and Marc, who is very helpful, is afraid that cable is just not able to cope.
 
 If installing AHI 6 is not helping, Im quite sure the cable has to go. Then I have to find another way of connecting the thing.

[rvo_nl]

AHI 6 didnt help..
 
 @Paul1981 what screenmode is your machine running?

[rvo_nl]

Thanks!

I wish it was that easy.. But I will try this week.

[rvo_nl]

Can't you try your Prelude connected straight to the 1200 motherboard like it's supposed to be? At least that would let you know if it is a cable issue or not.

Hi, took me a few hours, but Ive got the machine running with just 2Mb. When I run a digibooster mod over AHI, there is no distortion. It doesnt matter if the clockport extension cable is connected or not. I was quite surprised by this. The only thing I have removed is the ppc + bvision. Any ideas?

Edit: With PPC+Bvision+256Mb connected, I stil boot into the same Workbench installation I am using now. In that situation, the output will crash the system.

[rvo_nl]

I like your thinking, but Im afraid its not going to help. I have just tried with a 030 card and have encountered the same issue. Also, Im doing this on a fresh Workbench 3.1 installation with no CGX installed.

As soon as an accelerator card is in place, the timing is broken. Then again, it could be broken without an accel card too, since the basic 020 is not able to play mods in realtime in that case and it may not have to shift as much as data in that case. Just guessing.

[rvo_nl]

AHI drivers are the right ones.

I fiddled around with Play16 today and noticed the same issue. Initially the output sounds fine, then a loud hiss follows, which sometimes dissappears, sometimes not, and it results in a crash from time to time.

Ive tried without the Blizzard by holding down '2', but had the same problem. Seems like something is broken or my system generates a lot of noise? Is anyone able to test and repair my Prelude?