ZX Spectrum +3 Sound Distortion Analysis and Fix

Опубликовано: 14 Июнь 2026
на канале: Noel's Retro Lab
15,478
965

We revisit the Sinclair ZX Spectrum +3 we fixed a few weeks ago and we attempt to improve the quality of the sound output. We compare the sound the AY chip produces on the Spectrum +3 to the Spectrum +2. We record some test sounds and compare the sound waves produced on the two computers.

We look at the sound amplifier circuit on the +3 and attempt to make sense out of it. We look at the AY signal and the amplified signal with an oscilloscope. Then we model the amplifier on a circuit simulator and attempt to fix the clipping problem.

Finally, we make a few minor changes to the +3 sound amplifier and run some tests.

Support Noel's Retro Lab on Patreon:   / noelsretrolab  

Links:
Original Spectrum +3 amplifier circuit: http://tinyurl.com/vmtcsaq
Fixed amplifier circuit (similar to Spectrum +2): http://tinyurl.com/qu4kx68

Music:
Glider Rider https://spectrumcomputing.co.uk/entry...
Astro Marine Corps (AMC) https://spectrumcomputing.co.uk/entry...
Cybernoid https://spectrumcomputing.co.uk/entry...

BASIC programs:
http://retrolab.gamesfromwithin.com/f...
http://retrolab.gamesfromwithin.com/f...

Additional music by nene https://opengameart.org/content/theme...

Connect with Noel's Retro Lab:
Discord ➤   / discord  
Facebook ➤   / noelsretrolab  
Twitter ➤   / noelsretrolab  
Instagram ➤   / noelsretrolab  

#zxspectrum #sinclair