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I know it's 2014 and you can get an MP3 player and 40 bazillion terabytes on a microscopic chip. But I want to build a 6502 based retro computer and, in a perfect world, I would order up about 200 SID chips.

Anyway, are there any mass produced audio chips these days that closely resemble the remarkable chiptunes of the 80's?

I've ordered four AY-3-8912's off eBay but I'd like to find something similar but still in production.

Oh, gutting vintage computers is out of the question. I restore them. Not gut them. ;-)

EDIT

I wanted to post a followup to those who are curious. Finding old vintage audio chips on eBay isn't too difficult. But, obviously, not for any kind of mass production.

Anyway, I have found an alternative using the Propeller chip from Parallax. Using that microcontroller, you can emulate with high accuracy the SID, AY-3-8910 and SN76489 chips. Each emulated chip resides in one cog (from 8).

SIDcog v1.3

SNEcog v0.6

AYcog v0.8

Pod
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cbmeeks
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  • Why not use a modern audio DAC, but feed it a waveform calculated by an emulated AT-3-8912 in a programmable logic device? – Theran Jan 29 '14 at 03:39
  • I was trying to avoid as much emulation as possible. And I don't know much about those devices. Do you mean like FPGA? – cbmeeks Jan 29 '14 at 03:46
  • You don't need a FPGA. Almost any MCU can do FM synthesis in realtime. – Ignacio Vazquez-Abrams Jan 29 '14 at 03:48
  • You need to clarify what it is you are looking for, since most readers will not be familiar with chips from the 1980s. What function do you want, exactly? What do you mean by "closely resemble"? Are you trying to design a replacement or hoping to purchase something off-the-shelf? – Joe Hass Jan 29 '14 at 03:51
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    What's wrong with sending your 8-bit audio data to a 16-bit chip, leaving the lower 8 bits set to 0? – Warren Young Jan 29 '14 at 07:10
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    Nearest modern thing I could find washttp://www.ti.com/product/tlv320aic3100 ; more on this later. – pjc50 Jan 29 '14 at 08:12
  • Why not try creating your own R2R styly DAC? This way you don't have to gut anything. – nkeck72 Sep 19 '15 at 16:56
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    Can I vote to change the name of this thread to "Where have all the 8-bit sound chips gone?"? – RYS Sep 20 '15 at 00:57
  • @user5175284 read my original question...I mentioned I would never gut a vintage piece of equipment. Also, I decided to use the propeller as the emulation is very good. – cbmeeks Sep 21 '15 at 12:18
  • @cbmeeks Links are dead. I've edited them to use the wayback machine. Hopefully they point to what you intended. – Pod Feb 02 '21 at 11:57

2 Answers2

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As RedGrittyBrick says, they're not in production any more.

It's worth stepping back and asking why, and what's replaced them. There are three obvious candidates:

  • SID. This was synonymous with the C64, a product of the same company, and therefore died with MOS technology/Commodore. It was also a mixed-signal chip containing a number of nonlinear analog filters and artefacts that contribute to its 'unique' sound. Like valve amplifiers, it's not an accurate sound but a sound that people are fond of.

  • Yamaha OPL series (as used by Sega, Adlib etc). This was developed as a byproduct of Yamaha's instrument business. Pure digital, not mixed-signal. Yamaha have abandoned the FM synth approach and now use wavetable in their instruments.

  • Texas Instruments SN76489 (as used in the BBC micro). Again a digital direct synthesis chip that simply produced square waves. That functionality is trivial now on even a low-speed microcontroller.

Commercially, everyone is using either sample-based sound generation or digital direct synthesis from an algorithmic version of FM. Analog mixed-signal chip design is difficult, consumes a lot of chip area, and frequently requires expensive bugfixing. No sensible manufacturer is going to do one of those when there's no market.

Whereas doing it in software is cheap, accessible, and much easier to debug and tune. You might want to add external analog filters, if you're doing your own boards and don't care much about cost. Or there might be milage in trying to make one of the cheaper CPLDs emulate something like the OPL chipset. The Atari 2600's TIA should definitely be duplicatable, although the original design is incapable of producing notes that are in tune.

pjc50
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    The TIA can produce notes that are in tune pretty well, if one either limits oneself to a relatively small selection of pitches or doesn't mind having the main CPU help out quite a bit. I've done four-voice music on the TIA with a five-octave chromatic range, albeit at a CPU cost of 46 cycles per scan line. – supercat Oct 13 '14 at 21:14
  • interesting summary, thank you. – danmcb Feb 02 '21 at 14:51
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Where have the 8 bit sound chips gone?

No longer in production due to lack of demand.

in a perfect world, I would order up about 200 SID chips.

Too late

are there any mass produced audio chips these days that closely resemble the remarkable chiptunes of the 80's?

There's the things used in musical greetings cards and things like this - but thats resemble in the way an iPod resembles a Walkman. It fills a vaguely similar niche but uses very different technology.

There's also SwinSID

SwinSID is a hardware replacement for legendary SID sound chip

RedGrittyBrick
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