Music Machine

The Ram Music Machine

A digital sound sampling and playback device. The Music Machine was built by a British Company called Ram Electronics.

The Amstrad CPC version was almost identical to the the ZX Spectrum version, only difference was the address decoding logic.

The Music Machine came with a simple microphone. Recording quality could be improved by using a better(and more expensive) microphone. It came with its own sound sampling software and a sequencer.

No known emulator supports the Music Machine. There was a club advertised through the magazine Sinclare User which sent out a computer tape twice a year full of interesting software developed for the Ram Music Machine. This was contributed to by the members and included thing such as a 128k sampler, fsk syncing mods to the original software and many useful midi tools to name but a few.

The Music Machine was never used for producing sound effects in Demos.

Technical Specifications

Information from the manual:

The Music Machine incoporates two Ferranti devices for digital-to-analogue (DAC) and analogue-tod-digital (A to D) conversion. The part numbers are ZN429E8 and ZN449 respectively. The circuit also include a Motorola 6850 ACIA chip (Asynchronous Communications Interface Adapter) for handling the MIDI channel, two anti-alias filters (one for input and one for output), a discrete microphone amplifier and a headphone amplifier. The clock signal for the ACIA and the ZN449 is provided by a ceramic oscillator.

The incomming signal from the microphone amplifier is sampled to an 8-bit resolution at a rate of 19.444 thoudsand samples per second. This yields an analogue bandwidth of approximately 9.5KHz which is in fact the cutoff frequency of the filters.

All of the devices on The Music Machine data bus are accessible to the Amstrad within its I/O space. ACIA transactions must use 16-bit IO instructions; the converters are accesible via 8-bit IO instructions.

I/O MapPortMeaning
ADC START	&F8F8	Reading or writing to this port will start analogue to digital conversion
ADC READ	&F8F4(Read only)	The contents of the A-to-D can be read via this port. Note that the A-to-D must have been startet at least 20uS before this port can be read
DAC WRITE	&F8F0(Write only)	Data can written to the DAC via this port
INTERUPT SEL	&F8E8(Write only)	Writing 01 to this port disables internal Amstrad interrupts and replaces the IRQ signal from ACIA. Writing 00 restores normality.
ACIA Status	&F8EE(Read only)	Se Motorola datasheet
ACIA Data read	&F8EF(Read only)	Se Motorola datasheet
ACIA Control	&F8EC(Write only)	Se Motorola datasheet
ACIA Data write	&F8ED(Write only)	Se Motorola datasheet