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Philips AH578

Stereo Power Amplifier

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Philips AH578


Power output: 210 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 30kHz

Total harmonic distortion: 0.08%

Damping factor: 90

Input sensitivity: 1V

Signal to noise ratio: 100dB

Speaker load impedance: 8Ω (minimum)

Dimensions: 200 x 457 x 381mm

Weight: 28.6kg



Set AH673, AH572, AH578

I´ve bought the whole set, with defect poweramp AH57 (one channel)
I heard that this is "usal" for this poweramp, knows anybody the reason for this behavior? The replacement type for the power transistors 355N1 is the MJ15025, or is there a better type available?

Thanx Tandberg


I designed the AH578 when I was an electronic design engineer at Magnavox/Philips in Fort Wayne, Indiana. While I no longer have schematics and information for the AH578, I may be able to answer some questions.


Hello Earl!

Thank you very much for your reply.
So I´ve a few Questions:
All transistors in the schematic are coded, can you remember what "REAL TYPES" the have been. The next question: there is story in Europe, that only 400 pcs have been produced, is that really the truth?
If you need the schematic I will mail it to you and maybe you can make some remarks on the "coded Parts" ;-)

The whole equipment (AH578, AH673 and AH572) is now still working very very well, but who knows, tomorrow.....than it would be very comfortable to have "normal Designations" to find suitable replace parts, because I will never miss my "babies"

Thanx for your answers
Regards, Karl Trutschl

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