sampling sound using cpc+ analogue port

TFM · 23:44, 30 September 16

Quote from: Bryce on 22:22, 30 September 16
PWM is a digital signal, it would need to be decoded, not just amplified.

Bryce.

Would be great if somebody could show how to wire it.

TotO · 04:27, 01 October 16

No decoding is required... Just add a lowpass filter and listen the analog result.
You can out stereo 8bit or mono 16bit with a 57.5kHz maximum accuraty with the MiniBooster.

https://www.youtube.com/watch?v=tCmaOb-VAEo

Bryce · 10:41, 01 October 16

Ah, I thought it was a proper PWM encoded binary, so it's just a PWM of the analogue voltage levels.

Bryce.

Gesendet von meinem Motorola DynaTEC 8000X mit Tapatalk.

TFM · 01:30, 02 October 16

Aha, ok, if somebody will build one, I'll happily buy it.

zhulien · 13:35, 02 October 16

Me too. Today i was playing with the cpcbooster+. Didnt know the minibooster preserved the audio playback. Id rather the minibooster given the formfactor. I also was wondering how to get audio out in the most convenient way. Pitty playcity didnt have an audio in for daisy chaining/amplifying. Dont really want 3 sound systems to hear all the cpcs audio too... on the amdrum i was able to wire the audio out back to the audio in on the expansion bus. Can minibooster or cpcbooster+ work that way?

TotO · 21:06, 02 October 16

Quote from: zhulien on 13:35, 02 October 16Pitty playcity didnt have an audio in for daisy chaining/amplifying. Dont really want 3 sound systems to hear all the cpcs audio too...

It is not the Playcity work to mix the differents audio sources... $:-\$
Better to use an external audio mixer box to manage all the sources with the good amplification.

zhulien · 03:35, 03 October 16

Quote from: TotO on 21:06, 02 October 16
It is not the Playcity work to mix the differents audio sources... $:-\$
Better to use an external audio mixer box to manage all the sources with the good amplification.

Please don't take it as a criticism. Playcity is great

Still i wished it did that to fix the deficiencies in everyone else's audio solutions.

TotO · 09:17, 03 October 16

I don't take that bad, I just said that is not his job.

It would have made the board more complex to not solve all the mixing problem.

Bryce · 08:55, 04 October 16

Quote from: zhulien on 03:35, 03 October 16

Please don't take it as a criticism. Playcity is great Still i wished it did that to fix the deficiencies in everyone else's audio solutions.

My version of the DigiBlaster had an Audio input to allow daisy-chaining of sources.

Bryce.

TotO · 09:22, 04 October 16

Quote from: Bryce on 08:55, 04 October 16
My version of the DigiBlaster had an Audio input to allow daisy-chaining of sources.

Yes, but it is not a good way to process. Serial mixing by chaining only destroy the sound quality each time that you will add an audio source.
A clever way will be to use an external parallel mixer with audio amplifiers powered by at less +12Vcc.

EDIT:
To understand better how audio mixing is a pain in ass, here the schematic for 3 mono channels.
You require two times this for properly mixing 3 stereo inputs.

Bryce · 10:11, 04 October 16

Yup, to do it properly you need to normalise the signals and the mix them through a single op-amp. In the case of the DigiBlaster, I just wanted a very simple (cheap) method of allowing the AY output to come out the same speakers as the DigiBlaster sound. I also had the problem that I didn't have a power source on the printer port to use.

Bryce.

TotO · 10:17, 04 October 16

Yes, exactly!

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sampling sound using cpc+ analogue port