Where the hell is the dual AY / Stereo mod for the CPC range?!

Started by abraXXIous, 12:00, 17 April 13

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abraXXIous

Well? Where is it? You have Dual Sids on the C64, Stereo Pokey on the Atari 8 bits, Ive seen some form of stereo mod for the Speccy but I have never seen anything for the CPC.


Is there are reason for this? How difficult would it be to install a dual AY system?

Bryce

Technically it wouldn't be a problem to do, just no one has done it, becasue it hasn't been asked for. I even designed a stereo SID for the CPC, but I never built it.

Bryce.

abraXXIous

Hey there Bryce!


Well, sids would be going against the nature of the cpc surely? :) But two AY chips.... even if you had a switch so the secondary AY could be on the same address as the first except with a 10ms delay (so you would get a funky echo/reverb effect for all sound/music), and switchable so that the second chip could be on a different address block for 6 channel music etc.


How hard would this be to do?

TotO

Quote from: abraXXIous on 12:00, 17 April 13
Well? Where is it? You have Dual Sids on the C64, Stereo Pokey on the Atari 8 bits, Ive seen some form of stereo mod for the Speccy but I have never seen anything for the CPC.

Is there are reason for this? How difficult would it be to install a dual AY system?
It was done and shown by SyX at Retro Madrid 2013. (4:58 on this video)


Un paseo por RetroMadrid 2013 (09/03/2013) - YouTube
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

ralferoo

Quote from: abraXXIous on 12:39, 17 April 13
even if you had a switch so the secondary AY could be on the same address as the first except with a 10ms delay (so you would get a funky echo/reverb effect for all sound/music) ... How hard would this be to do?
Adding a delay would be quite tricky, as you'd need to store all AY accesses into a circular RAM buffer and replay them 4000 clock cycles later. It's doable, but it'd add a lot of complexity over just having a 2nd AY chip. That said, on an emulator it'd be almost no effort.

abraXXIous

What if you simply added an analogue buffer and delay? Surely that could be done with a few discrete components?


Even if this was not possible, would it be possible to (again, using a simple analogue circuit, no digital processing) transpose the output of the second AY up or down one octave?

TotO

Quote from: abraXXIous on 13:17, 17 April 13
What if you simply added an analogue buffer and delay? Surely that could be done with a few discrete components?

Even if this was not possible, would it be possible to (again, using a simple analogue circuit, no digital processing) transpose the output of the second AY up or down one octave?
Like said 3 posts over, it was done... (and more simply)
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

abraXXIous

Quote from: TotO on 13:25, 17 April 13
Like said 3 posts over, it was done... (and more simply)


So which one was done? Echo effect or transposition?

TotO

The board add a second sound chip on the expansion connector that allow to play 3 more AY channels using a different port.
It can be set to replay CPC or ST sound frequencies, w/o programming the PIO.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Sykobee (Briggsy)

Quote from: TotO on 15:00, 17 April 13
The board add a second sound chip on the expansion connector that allow to play 3 more AY channels using a different port.
It can be set to replay CPC or ST sound frequencies, w/o programming the PIO.
I was going to ask if it supported a 2MHz mode, so that's a neat feature. Next step - piggyback the AY on top of the existing AY inside the CPC and provide both with 2MHz options :-)

abraXXIous

Quote from: Sykobee (Briggsy) on 15:40, 17 April 13
I was going to ask if it supported a 2MHz mode, so that's a neat feature. Next step - piggyback the AY on top of the existing AY inside the CPC and provide both with 2MHz options :-)


Sounds like a project for someone with the hardware hat on.... Bryce? :)

Bryce

TotO and SyX are well capable of doing a project like this. They don't need me.

Bryce.

TFM

Quote from: abraXXIous on 12:00, 17 April 13
Well? Where is it?

It's not needed, because the CPC's AY does produce stereo by itself - in contrast to the mono sid of the c64.

The native CPC already does stereo - just connect your stereo amplifier.

For more you have to wait until a near hardware release. It's not my job to take the surprise away, but your patience will pay off.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

abraXXIous

Quote from: TFM/FS on 19:09, 17 April 13

It's not needed, because the CPC's AY does produce stereo by itself - in contrast to the mono sid of the c64.

The native CPC already does stereo - just connect your stereo amplifier.

For more you have to wait until a near hardware release. It's not my job to take the surprise away, but your patience will pay off.


Well, stereo sound is not what I was getting at, dual AY would double the number of available voices... so no clues as to what this impending hardware release is.... besides something CPC and audio related? :)

Octoate

Such a daughterboard was described in a hardware book by Data Becker. I am not sure if it was published somwhere else, too. Maybe I have enough time to scan the schematics and put them into a Wiki page this weekend...
--

McKlain

TotO can correct me if I'm wrong, but in their mod the second AY (or YM) plays the sound in mono.

TotO

True.
On the prototype shown at Retro Madrid, the board replay 6ch music through the embedded speaker (mono).
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

arnoldemu

Quote from: abraXXIous on 22:25, 17 April 13

Well, stereo sound is not what I was getting at, dual AY would double the number of available voices... so no clues as to what this impending hardware release is.... besides something CPC and audio related? :)
wait. I am sure it will be worth it.
My games. My Games
My website with coding examples: Unofficial Amstrad WWW Resource

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