Is your Commodore 64 working great but has no sound output? The 6581/8580 SID is very fragile and can be damaged easily, or just break down over time. It can be very expensive to replace your SID with an original chip, and even then it is not guaranteed to last. BackSID replaces the essential functionality of the SID, offering a faithful reproduction and a delightful similarity to the original, being hard to distinguish in some cases.
BackSID is uniquely hand-assembled in the USA and individually tested.
As compared to SwinSID: Much better & more accurate emulation, boasting over 5 times the processing power. Supports paddles, mice, diagnostic harnesses, and even koala pads (unlike SwinSID). Tested to work perfectly with classic game music, sound effects and speech.
As compared to ARMSID, it is a close match, but BackSID has some advantages. BackSID is much louder, has a deeper bass sound, and comes with a high quality Burr Brown op amp. Easier to use, configure, and upgrade firmware.

Replace your missing or broken SID with BackSID™ for Commodore 64/128:

• Acts as fully compatible replacement for the 6581 or 8580 SID chip in all C64 and C128 revisions;
• Sound is faithful to the original SID and gives correct intonation on most classic games;
• Loud, clear, and punchy sound will not disappoint;
• Supports analog & PWM potentiometer reading, allowing proper functioning of paddles, mice, and diagnostic harnesses;
• Configurable settings, including overdrive, filter mode, and smoothing;
• Firmware is upgradable by running a program file from your Commodore 64/128;
• Note: The infrequently used audio passthrough feature is unimplemented.