Last modified on 29 June 2010, at 14:45

Digiblaster

Revision as of 14:45, 29 June 2010 by Bryce (Talk | contribs) (DigiBlaster V3)

Digiblaster is a small hardware device plugged into the CPC's printer port to play 8-bit mono sound samples. It was designed by Face Hugger and printed in the German magazine CPC Amstrad International in issue 8-9/1991. In 1995(?) Joshua made a redesign for better sound quality.


Software supporting Digiblaster

Demos

Utilities

DigiBlaster V2



DigiBlaster V3

This main difference with this version of DigiBlaster is the additional Line-in connector which allows the user to feed the AY output through the card so that both sound sources get played through the same speakers. The DigiBlaster has been made dual-mono so that both speakers play the sample as is done with the AY-3-8912 Channel B. The variable resistor RV1 adjusts the Digiblasters output level to balance it to the AY level.


DigiBlaster3 Schematic.PNG


The diodes in the original version have been removed, because they served no meaningful purpose and an R2R ladder design was used for the DA conversion. This not only improves the linearity of the DAC greatly, but it also ensures that the output impedance remains stable and of course means not having to buy 8 or 9 different non-standard value resistors. The completed devices look like this:


DigiBlaster3 Types.jpg


Track layouts have been made for both Centronics and Edge-connector. As seen in the picture above, the layouts use isolation displacement connectors (the type usually intended for flat cable) which have been modified (ie: the plastic band and clips removed) so that it can be mounted directly to the PCB. 1.5mm FR4 PCB should be used preferably to give the circuit stability.

Resources

File:DB3 Edge Layout.pdf - PCB Track Layout for Edge Connector Version

File:DB3 Cent Layout.pdf - PCB Track Layout for Centronics Connector Version