Replacement for Ancient Philips BD182

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#21
Recommend ON Semiconductor 2N3055G.
ST made the only other device I would use, but no longer.
2N3055 has been "copied" so many times I agree, it is pot luck without specifying manufacturer.
Another option might be ST's look-alike TIP3055. Should be possible but collector lead needs to be snipped off and case used - as long as the screw holding it down is the one used in the original amp (they may have used the hole nearest the E/B leads, and with a plastic case you would not have a contact without rerouting).
(I guess you could actually use the collector lead in that case, by passing the wire through the unused mounting hole (but with a good heatshrink insulation on it after soldering).
 
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#22
john_ellis said:
First simulation results suggest:
- remove C3, C6, C7, R12 and C5.
Add a 220 pF capacitor in series with a 100 ohm resistor and connect between the collector of Tr2 (BD139 VAS) and emitter of Tr1 (PNP input).
Caveats - this method was used successfully by Dr Bailey. It requires a low input impedance to keep the frequency response of Tr1 high. Depending on the pre-amp you may need to do one or more of the following:

(a) add a 1.5k resistor in series with the input (C2) and if that makes little difference add a 100pF from Tr1 base to ground.
(b) if your power supply leads are longer than 100mm between the PSU caps and the supply rails, add 100uF caps locally, connected from the PSU + rails on the amp PCB and common ground point.

Simulations did not reveal any oscillations in the output, after swapping between devices, but there were oscillations internally, in Tr1, (not a good sign) which were eliminated by the pahse lead compensation above.
Click to expand...
I will try it out .

Thanks everyone
John's work can be used to make a modern version of this circuit .

Edit: I actually ordered 8 pieces of BD183 . [ Well 8 pieces , i will leave some for my grand child to fix this amp after my death ] [Hope they turn out Genuine ]
 
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