Parallel TDA7293 with Input Buffer

I built an amplifier using several TDA7293 chips connected in parallel to make good use of my extra stock. The result honestly surprised even me!

I added a buffer stage at the input using opamps like the OPA1641, OPA1655, or OPA627, because I'm using an ALPS RK27 potentiometer for volume control directly at the output of a NOS DAC.

If you prefer, you can easily disable the buffer. Simply remove the opamp and short pins 2 and 3 of the socket.
In this case, R2 should be 47K, and you should remove both C23 and R1.
If you would like to keep an RC-filtered input instead, use R1 = 100Ω and C23 = 100pF.

Now, I’m excited to share some measurements with you!



EPIC W
IMG_2218.jpg



1W Measurement (2x42VDC)
buffered Parallel TDA7293 1W.jpg



Output Noise (input shorted)
buffered parallel TDA7293.jpg



Schematic
Parallel TDA7293 sch.jpg



Positive Regulator
posreg.png



Negative Regulator
negreg.png
 

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