SID

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SID

Postby Chris » Fri Apr 19, 2013 2:11 pm

Hi Simon,

I have a chance of a few scrap C64s (the amiga style case) from what I read the purists say that one version of SID is 'better' than others. Has your research turned up if these can be found in later C64s or are they only in earlier versions?

Regards

Chris
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Re: SID

Postby simon » Fri Apr 19, 2013 2:47 pm

Hi Chris,

it is hard to say which SID (6581 or 8580) sounds better. As far as I know the newer 8580 has some problems playing samples (which are more quiet). In the end it probably depends on which music you personally prefer. Older music sounds better on an 6581. "Newer" music sounds better on an 8580. But this is only a thumb rule whereupon it depents on the SID which is used by the musician.
Some say the 8580 sounds more clean and the 6581 sound warmer. I think you can compare both with the help of Vice though the SIDs are emulated only.

Regards
Simon
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Re: SID

Postby varaktori » Sat Feb 15, 2014 11:42 am

I think 8580 is less noisy. Future versions it would be nice to have also OPL4 chip and/or AY-3-8910. Maybe AY-3-8910 sound output connected to SID chips sound input pin so that you can use SID filters with AY-3-8910?
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Re: SID

Postby simon » Mon Feb 17, 2014 1:57 pm

You are right. the 8580 sounds more like it should. But in the end it depends on the SID music you want to listen to. The 8580 doesn't play samples very well. I would guess that the music sounds best on the particular SID which was used when composing.
I once considered an OPL4 and it still is in my part-box but never used it. Maybe for Kiwi V3 Rev 2 in a few years? :) ;)
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Re: SID

Postby varaktori » Mon Feb 17, 2014 8:51 pm

C64-Wiki wrote: In the later 8580 model this "bug" was fixed and samples were inaudible, but it is possible to revert this by soldering a 470k resistor or, if you want to be able to adjust the level, a 1M pot in series between EXT IN and GND. Even better sample playback can be achieved by altering the pulse width modulation register, which can hold an eight bit value.


http://www.c64-wiki.com/index.php/SID

Commodore 64 also have differences of 6581 and 8580 audio out circuits:

http://koti.mbnet.fi/malinto/dualsid/faq.shtml

I have not tested that fix myself. Another interesting PSG is SAA1099 and then we of course have SN76489. I want them all... :D
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Re: SID

Postby Chris » Mon Feb 17, 2014 10:03 pm

varaktori wrote: Another interesting PSG is SAA1099 and then we of course have SN76489. I want them all... :D


Not got any SAA1099's interestingly that chip has a /DTACK signal :o . I do have ym2203's (AY3-8910 compatible) , real AY-3-810's, YM2419, YM2608, YM2610, YM3812, SN74694 and ymf262. I also have a whole bunch of ADPCM chips for playing samples and voice synthesis chips which should liven things up. Thanks goodness for 1980's arcade machines :lol:
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Re: SID

Postby varaktori » Mon Feb 17, 2014 10:16 pm

Chris wrote: Thanks goodness for 1980's arcade machines :lol:


If I remember right many of them has secondary processor just for sound. :)
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Re: SID

Postby Chris » Mon Feb 17, 2014 10:25 pm

varaktori wrote:If I remember right many of them has secondary processor just for sound. :)


Correct many used a Z80 for the sound processor, early ones used an 8255 PIO to pass 8 bits of data for which sound to play and another port for the handshaking.
Capcom CPS series had 68000 main processor with Z80B sound processor.
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Re: SID

Postby simon » Mon Feb 17, 2014 10:37 pm

Wow, I didn't know the SAA1099 (by name). Doesn't sound too bad.
I could imagine some OPL4 or even an DMA sample sound engine (like done on the Amiga) instead of another CPU. DMA once was on my wishlist anyway.
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Re: SID

Postby varaktori » Mon Feb 17, 2014 10:50 pm

OPL4 for game music and those SID chips for sound effects is good combination for future kiwi. ;)
And yes, I want refresh my assembler programming memories and write some games. :D
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