The Sinclair QL Forum

me to...

If you are one of the lucky ones with a SGC with PAR port...

Edit : see later in thread for latest AYplayer version

mk79 wrote:Does anybody know how the clock for the AY chip is derived? I don't understand this from the posted PCB photos.

I did a rough schematic of QSound when PCB was posted. From what I saw it uses 750kHz E clock (60/40 duty). The AY data sheets specifies minimum 1MHz and 50/50 duty. But Bumble bees fly...

Silvester wrote:I did a rough schematic of QSound when PCB was posted. From what I saw it uses 750kHz E clock (60/40 duty). The AY data sheets specifies minimum 1MHz and 50/50 duty. But Bumble bees fly...

As I wrote the QSound software calculates its frequencies for a 1.5Mhz base clock, so the E signal is only part of the equation it seems.

mk79 wrote:

Silvester wrote:I did a rough schematic of QSound when PCB was posted. From what I saw it uses 750kHz E clock (60/40 duty). The AY data sheets specifies minimum 1MHz and 50/50 duty. But Bumble bees fly...

As I wrote the QSound software calculates its frequencies for a 1.5Mhz base clock, so the E signal is only part of the equation it seems.

IMHO I think you'll find your'e an octave low

Edit: i.e. anything played on a QSound emulation (at 1.5MHz) will sound octave low on a real QSound (0.75MHz)

Silvester wrote:If you are one of the lucky ones with a SGC with PAR port...

Dual AY on a PAR port? Cool. I only have one single chip solution at the moment, need to have closer look at that. I do think that two chips is the minimum for it to get fun.

Silvester wrote:

mk79 wrote:

Silvester wrote:I did a rough schematic of QSound when PCB was posted. From what I saw it uses 750kHz E clock (60/40 duty). The AY data sheets specifies minimum 1MHz and 50/50 duty. But Bumble bees fly...

As I wrote the QSound software calculates its frequencies for a 1.5Mhz base clock, so the E signal is only part of the equation it seems.

IMHO I think you'll find your'e an octave low

Possibly. I found so many bugs in the QSound code that this wouldn't astonish me that much really. By the way, my new QSound code will support two chips, too, as I intend it to act as the low-level software abstraction layer for QPC.

mk79 wrote:I found so many bugs in the QSound code that this wouldn't astonish me that much really.

Blame Jochen Merz for it. It is his code, I think.

I don't blame anybody for >30 year old code.

By tendency I would rather blame someone for 30 years old code, written by a young brain making money with the QL, than us ageing hobbyists for today's code. (Not that I blame Jochen.)