My second piece of hardware that I am releasing today goes back to my roots with computer audio - this 'SID Interface' started out just as a small pet project for myself exploring old forms of computer sound.
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 requires a 12v input to power the SID chip (any 12v PSU that can supply 100mA can be used, I have fitted a standard 2.1mm power socket to the board - A suitable plug top PSU can be bought for around a fiver in places like Argos). A 3.5mm speaker socket is also on the board for connecting some speakers to it. 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. I do have a couple of 6581 SID's from old C64's which I bought when designing this hardware, and I can supply you with one if required and I can easily track down some more C64's for more. I have put together two disks to go with the SID Interface, featuring a couple famous tunes from the C64 to show off the SID chip in action. The SID Interface is available now, priced £28.99. Again piccies can be found on the website. (As a side note - there is an interesting exhibit at the "Game On" exhibition which allowed you to listen to a lot of old computer music - mostly from the C64... the exhibition I think is still at the Royal Museum of Scotland in Edinburgh just now (I went to see it in November)) Colin ==== Quazar : Hardware, Software, Spares and Repairs for the Sam Website: http://www.quazar.clara.net/sam/ Issue Three of "Sam Revival" Magazine Out Now !
