IREF, the secret of the TDA1545A

[Eric Juaneda]

I never find that datasheet for TDA1545A is very clear. There are a lot of interrogations about the interesting IREF pin. You can find on this forum many threads speaking about.

For the Jundac Five, I test various configurations for IREF, starting with the standard one recommended by Philips. Each configuration for IREF changes sound rendering. This pin is very sensitive and affect: tonal balance, subjective definition, stability of music, precision, bass depth...

The standard configuration recommended by Philips gives a very rounded sound without much details; very pleasant but not very realist! The solution that I develop for the Jundac Five pushes the audio quality far away.

For the final kit, I develop a reference tension in discrete technology. The IREF pin is driven by low impedance reference tension (VREF). For VREF, the quality of each component is crucial. Low noise transistors and high quality capacitors like polypropylene film are used to drive this crucial pin. Using electrolytic capacitor degrade sound rendering by masking details and reducing subjective definition.



With this original driving, the TDA1545A reaches unknown dimensions with very large and strong bass, good definition and fine treble. It changes from all other realizations.

[Eric Juaneda]

A picture of VREF