Thursday, August 26, 2010

LM4780 + TDA7293 Power Amplifier

National Semiconductor LM4780(Stereo Treble) 120watts
ST Microelectronics TDA7293(Mono Bass) 100watts


- 60Wx2(stereo) + 100W(bass)
- this amp is well designed and built with great quality and accuracy components for its best frequency reponses.
- 1% tolerance resistors, film capacitors signal path/powerail decoupling, semi-gold plated 8-DIP sockets,
- WIMA MKP4 input coupling capacitors, Nippon-chemicon powerail capacitor(well known for DIY power supply cap, Nichicon LQ power filter capacitor(seen a lot in Tube amp) and etc..

- preamp stage two NE5532 opamp, (woofer loudness control, crossover control(50~150Hz), and volume control)

- when there is no woofer connected, cutoff to fully stereo channels automatically which no need to tune the crossover point again to the lowest.

Trying on smaller heatsink because not going to maximize the volume.

Dynamic quite good.
This is an GREAT amplifier, I don't even know it is already on after I powering on it in the 1st time.
It is dead silent, can't hear any hum or hiss 1 inch away from tweeter.

Changed RCA interconnects, cut off the internal preamp and removed TDA7293.

Sounds faster, airy and cleaner without NE5532 preamp.
and lesser harsh with the changed from standard RCA to coaxial RCA.

This is my another new PCB board, planning to redo it.


  1. nice amp.
    can i have an audition with it?

  2. still in process, left heatsink and transformer.
    going to rebuild whole circuit with better components. you can get LM4780 DIY stereo amp for fair low price from the net around USD$30-70. =]

  3. where did you get a LM4780 + TDA7293 Power Amplifier board?

  4. I ordered the new un-soldered package but the seller sent me soldered package and some crack on the board during shipping, so he send me another board.

    You can get this amp from =]