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16

The amplifier input is biased to about half supply voltage. The SID output is also biased to about half supply voltage. You have little or no bulk/bypass capacitance on the 9V supply pins, so abruptly disconnecting the 9V supply from amp also abruptly shuts down the amp input bias. But as you have the quite excessively large 22uF coupling capacitor between ...


14

The output is analog, not 8-bit. Each channel has an 8-bit DAC inside to generate the selectable waveforms (sine was not one of them, square/pulse wave, triangle and saw). There were also volume and envelopes, so even at this point the audio can't faithfully be represented at 8 bits. There is also an analog filter through which channels can be sent. The ...


9

Part 1: Was the output of the C64 SID chip 8 bit sound? Short Answer: yes The term 8-bit sound is generally not related to any sample size or speed, but to describe the sound 'qualities' of the 8-bit generation of consoles/computers. Part 2: So is it correct to say that the audio generation part was really analog, Each and every sound generation is in ...


4

I'm not sure about built-in support for rendering per-track wave files automatically, but you could write a batch file or shell script to drive a command-line SID-to-Wave tool to play it multiple times, leaving a different channel un-muted each time. JSIDPlay2 can be used that way. ✓ Works on all major platforms ✓ Supports your choice of cycle-accurate ...


4

Or maybe what I am really asking is: If I have an 8 bit, 44 kHz sample based audio chip, could that chip generate audio which could not be distinguished from a real SID chip? The short answer: probably. But, given a choice, use standard 44.1 KHz 16-bit sampling to reproduce the signal. PCM audio reproduction has two components: frequency range (what's ...


3

One might select sampling rate to be half the display lines rate (around 7.8 kHz) and arrange things so, that CPU always gets interrupted to play digital at odd lines, not interfering with bad lines.


3

Looking at a series of stepped die shots, and knowing that the steps were 0.5mm one way and 0.45mm the other way, we can estimate the die area as about 27.2 mm².


2

While not exactly examples of outstanding music, I knew that there was a C128 demo program written in BASIC to show off the capabilities of BASIC 7.0. In addition to graphics, it also demonstrated some music capabilities. I believe the 8-bit Guy featured it in his Commodore 128 video on history of Commodore, but there is also another one that I found from a ...


2

The waveform generator and DAC of each of the three voices is 12-bit, and calculates a new value for the DAC at the system clock speed, approximately 1 MHz. The subsequent envelope generator and filtering is done in the analogue domain, so in general the output is unquantised.


2

This sounds like an ESD/over voltage event might have occurred while you were working with the circuit. The SIDs are extremely sensitive. It is not uncommon for a defective SID to draw excessive current. (This is not going to bring back your SID, but just a tip for future work: while prototyping your project, consider using a SwinSID (Nano) instead - it's ...


1

For the records: I just found some C128 BASIC music program using PLAY commands in the Dual Demo by Flexman The music code is at line 7000 and following.


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