MainHELP Glossary Hardware SAL Workshop Companies FTP ToolsBackAbout

Increase Digital Volume

Project: Increase volume level of the SID's digital output
Target : C64 (new boards with 8580)
Time   : 20 min.
Cost   : <1 US$
Use    : Make digital voice (switching volume on/off rapidly) as
         loud as the other ones so that it will not be drowned out.


Connect the SID's audio input to GND via a 330k resistor (optimal value may vary).




  1. Select a tune containing a digital voice (e.g. Iron Maiden), listen to it and remember the volume.
  2. Pull off all cables and open case.
  3. Solder the resistor between pin 26 (EXT IN) and pin 14 (GND) of the IC socket carrying the SID, optionally via the switch. If you have a potentiometer, you should try this first. When the volume of both digital and non-digital sound is okay (is about equal), measure the resistance of the potentiometer and solder in a resistor of that value.
  4. Listen to the selected tune again and check the volume. Listen to non-digital music, too, and check if the volume is roughly as loud as the digital volume.
  5. If the volume seems to be okay, close the case again, otherwise experiment with the resistor's value (or use a potentiometer).

    Note! The smaller the resistor's value, the more silent is the non-digital music, so you have to check BOTH the volume of digital and non-digital ('normal') music when you experiment with the resistor's value!

Possible failures

Updated: January 7th, 1998
Created: March 17th, 1997
Status : Verified on September 23rd, 1997
Thanks to: Ghostrider / NoName for telling me about this trick

Site copyright © 1997 by Marc-Jano Knopp
This document is part of MJK's Commodore 64 & LCD Page
Brought back to life by Peter Schepers, Dec 10, 2005 because I really liked this site!