Upgrade of K8060 to 250W RMS output

Changes to K8060 to produce 250W RMS into 8R which some might find interesting.

This involves increasing supply valtage and upgrading various components.
Obviously will void limited warranty.

C12, C13 4700uf 80V (Nichicon type fits on board)
C7, C8 100nF 100V ceramic
C6 47nF 100V ceramic
C4, C5 470pF ceramic
C10 100uF 63V or 100V electrolytic

T3 ZTX857 glued to small heatsink (watch pinout as different from BC639)
T8 MJH11022
T7 MJH11021
D5, D5, D4, D3 P600D or bridge rec

R13 4K7 2W
R12 1K5 0.6W
R8 3K3 0.6W
R2 82R
R11 8K2 0.6W
R4 220R
R16 68R
R6 82R (higher than R16 as T5 sees much lower impedance on current limit)
R10 10R 0.6W
R19, R20 0.22R 5W
R18 47K

Heatsinks should be forced air cooled

Transformer 50-0-50V @ 500VA will power two K8060’s (Maplin)
Earthing between two boards should be strapped together with very low impedance braid/wire to avoid hum.
Use 40W bulb in series with mains supply to test and check 0V on LS+ before connecting speaker.
RMS power was measured using burst sinewave test signal. Should be OK into 4R load but not short circuit.

Interesting mod, thanks for sharing it.

Hi, what voltage is behind diodes ? On original is -+40 vdc? Is possible conncet dual voltage power supply direct instead of ac supply and diodes?
For main transistors 2sc52000 + 2sa1943?