The new 2014 Edition of the SID Interface
(Please note the interface is supplied without a SID chip)
The SID interface goes back to my roots with computer audio as this started out just as a small pet project for myself exploring old forms of computer sound. Now in 2014 I've revamped the circuit board and added some new improvements.
The 'SID' is the 3 channel synth shound chip used in the Commodore 64. Because it was so different to the style of the SAA1099 inside the Sam, I decided to wire one up and see how is sounded as the synths it produces are quite different. The SID chip can produce several shapes of waveform - square, triangle and sawtooth, and combined with controllable volume effects such as attack, decay and sustain to shape the sound. Add in a couple of other effects such as noise and ring modulation and the overall sound the SID can produce is quite unique and as a result it is still very popular amoungst computer audiophiles. (There are even interfaces to use them on the PC!)
The SID interface plugs into the euroconnector on the back of the SAM and gives a 3.5mm speaker socket for connecting some speakers to it.
This new 2014 Edition of the SID Interface has a built in DC to DC convertor to supply the SID chip with the correct voltage so unlike the original 2003 version an external PSU is no longer required. The circuit board is also a golden yellow colour marking the 25th Anniversary of the SAM Coupe, and is styled to match my other recent hardware such as the Trinity Ethernet Interface and the 2 Way Euroconnector Expansion card.
The interface is supplied without a SID chip - you'll have to get your hands on an old C64 and remove the chip (its usually in a socket so very easy to get out). As there are two types of SID (6581 - from the original C64, and the 8580 from the redesigned new-look C64) the interface has to be built up specifically for the chip that is going to be fitted. Please state which chip you have when ordering.
The SID Interface comes complete with a disk of software, featuring Simon Owen's marvelous .sid playback code. Using a software emulator to run 6510 machine code (the Commodore 64's processor) the SAM is able to run .sid music files in realtime (essentially partial C64 emulation on the SAM!) so there's now the ability to listen to thousands of C64 music files. The disk features a selection of some of our favourite tunes!
There is an indepth look at the SID chip, it's history and sound in an article in issue 4 of Sam Revival magazine.
It is a SAM Coupé... not a C64... It's just a fancy front end!
The new 2014 edition of the SID Interface is available now, priced £44.99.