After initial bench testing I decided to put the Felicia in the system powering various line level components. I monitored the output of the Felicia with a scope and dvm. I observed on the scope a fair amount of spiking around the zero crossing points of the output sine wave. I did not see this when I plugged in a 60 watt lamp to the Felicia on the bench. This must be from the rectifier diodes turning on and off in the line level units connected to the Felicia. I suspected that caps 5, 6,&7 at the very output of the Felicia might be exacerbating this problem, so I took them out and the spiking did reduce. I am still showing a fair amount of distortion in the output, but this is low frequency distortion and even the marginal power supplies that are often placed in consumer equipment are decent enough to crush this into near oblivion. With my FM tuner, and old, reworked NAD 1240 that I use as phono pre amp, my G&D transport and a turntable all on at the same time, I observed an output voltage of 110 to 111 volts rms. The AC line coming in was a nominal 117 to 118 volts rms. The voltage drop of approximately 7 to 8 volts does not appear to effect the line level equipment I am using. In the past I have tested for regulation on this type of equipment and most of this equipment will stay in regulation down to 100 to 105 volts rms. I should add that most of us can easily design a line level power supply that will stay in regulation to 95 volts rms.
Usually I get more line noise during the day and the Felicia did a superb job filtering that out and I did note that the FM Tuner was a bit quieter. I tried the Felicia hooked to the line level equipment I have built from scratch and got a bit of an impedance mismatch due to AC line level filters that I use at the AC input, but no reduction in noise that I could hear.
Paul and myself have had some long discussions on this issue and I suspect that good power supply design and grounding play an important role in how well a power supply rejects low frequecy noise. I should note that environment can also play significant role here. I am plagued by more HF artifacts than LF artifacts on the AC line. Paul tells me that apartment buildings can have plenty of both and I believe him. I reside at the moment in a 3 decker in suburbia.
I am leaving the Felicia in the my system for powering/filtering of my transport, tuner, phono pre amp and turtable. I do not consider the poor regulation of the Felicia to be of any real significance for my environment and application, and I never have my transport, tuner, and phono amp all on at the same time.
Thank you Paul; you have come with an excelllent unit for cheap money that really works, and for those people that know me I generally don't hand out praise very often.
Great job, and good design Paul;
d.b.
