Re: Apple //c sound - 3 channels plus noise?!

["Bill Garber" <willy46pa@comcast DOT net>]

"Richard Kilpatrick" <delorean@NOSPAMbtconnect.com> wrote 
in message BD268D8D.55F8%delorean@NOSPAMbtconnect.com">news:BD268D8D.55F8%delorean@NOSPAMbtconnect.com...
: Okay, this is probably one of those "well, duh!" 
: moments, but...
: 
: Seriously, I always thought that //c and enhanced 
: //e were pretty much identical. So any sounds that 
: emerged from the //c were the regular, friendly 'beep'.

Judging from the schematic and looking at the board itself, 
it appears that the //c has some sort of amplifying circuit 
that converts the speaker clicks into some type of triangle 
or square wave. I'd have to put the scope on it to be sure. 

Michael J. Mahon?, where are you on this?  :o) 

: So, I'm looking at a website, and there's a nice 
: description of the //c, including pictures of the 
: motherboard (an early one without RAM expansion - 

Ok, to clarify this. There was the FF rom which 
allowed a 5.25" external drive, the 00 which added 
the UniDisk 3.5" capability and I believe there was 
a ram card that plugged into the CPU and MMU sockets, 
the the 03 which had it's own ram expansion port, and 
finally the 04 which merely fixed a bug in the 03. 

Next we have the //c plus which was 05 and had the 
accelerated CPU, the ram port, and an internal 3.5" 
disk drive. I know all this thanks to those who have 
graciously maintained web sites with The History Of 
The Apple II.  :o) 

: Bill, the RAM expansion models are liable to be 
: uncommon in the UK, so I'd really like one - 

The ram expansion card for the 00 model is very 
rare and I doubt you'd get one for cheap. They 
tend to run in the $150+ range when they do appear. 
for the 03/04 model, they appear more frequently 
but still the price range is similar. It's a shame 
that I have one coming in with the ram card, but 
it is already spoken for.  :o( 

: I have  a spare PSU for my //c). 

If you mean the Brick, any 12-15 volt x 2 Amp 
supply will do. The wiring diagram for that is 
online several places. I also have it here. 
I have 5 //c's and only 2 Bricks.  :o( again. 

: I'm unsure of the guy's page, since he shows 
: the 80 column hardware and claims the //e has 
: it on board as well (what the hell was I doing 
: with extended 80 column cards then?!), but there, 
: clear as day, is an AY sound chip, as found 
: lurking in a lot of different machines.

The Platinum, or enhanced, //e has the 128K of 
ram onboard and you still need the 80 column 
card, and the extended card I believe will still 
add an extra 64K to the expansion ram. Am I right? 
Somebody?, Anybody?, Please???  :o)  

The AY chip is the keyboard encoder. I believe that 
AY is a MFG code so they can make other than sound 
chips.  :o) 

: Did anything ever use it? I never even knew the 
: //c had different sound capabilities, even when 
: I owned one.

I noticed from reading ahead in the thread that 
you corrected your error on the KB encoder.  :o) 

Bill @ GarberStreet Enterprizez };-) 
Web Site - http://garberstreet.netfirms.com
Email - willy46pa @ comcast DOT net
Change DOT to a dot to contact me



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