Lowering Aleph PSU noise

tortello · 4th October 2001, 08:52 AM

I've tried to fit the differential input stage of my Aleph with a small RC decoupling net, made by a 220R resistor and 100uF capacitor, to filter the power supply + rail (the cap's negative foil is wired with the negative rail).
The discovery of the hot water? Yes, of course.
Anyway, the PS noise at the amp output has decreased of about 6dB (mean value about 800uV, peaks of about 1.5-2mV) in spite of the net feeds a current source, and the input stage "sees" a purer +B rail, since the modulation of the +rail, made by the output stage current when an input signal is applied, is much lowered: this "might" (... maybe...) give also a better sound [maybe... :-) ].
The power in bump amplitude is increased of about 15%, the power-off transient is about the same, with these values.
Any experience about this?
Tortello

[Edited by tortello on 10-04-2001 at 05:43 AM]

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4th October 2001, 08:52 AM	#1
tortello diyAudio Member Join Date: Jul 2001 Location: Genoa (ITALY)	I've tried to fit the differential input stage of my Aleph with a small RC decoupling net, made by a 220R resistor and 100uF capacitor, to filter the power supply + rail (the cap's negative foil is wired with the negative rail). The discovery of the hot water? Yes, of course. Anyway, the PS noise at the amp output has decreased of about 6dB (mean value about 800uV, peaks of about 1.5-2mV) in spite of the net feeds a current source, and the input stage "sees" a purer +B rail, since the modulation of the +rail, made by the output stage current when an input signal is applied, is much lowered: this "might" (... maybe...) give also a better sound [maybe... :-) ]. The power in bump amplitude is increased of about 15%, the power-off transient is about the same, with these values. Any experience about this? Tortello [Edited by tortello on 10-04-2001 at 05:43 AM]