I can get some of these pretty cheap. RPS-120-MEAN WELL Switching Power Supply Manufacturer
But Nelson has said in another thread "The supplies should be rated above the peak of draw. For a single Aleph J that would be 3 amps or more per channel".
So two of these not enough it seems for two channels the datasheet seems to indicate that the de-rating will occur around 50 degrees C as well and they are not rated to 120 watt unless fan cooled apparently. I am trying to build a mini version of the Aleph J and don't want run into problems with power supplies not being capable for the load. I am looking at some PLC power supplies that might be a better choice since they are industrial grade but albeit a little more pricey.
But Nelson has said in another thread "The supplies should be rated above the peak of draw. For a single Aleph J that would be 3 amps or more per channel".
So two of these not enough it seems for two channels the datasheet seems to indicate that the de-rating will occur around 50 degrees C as well and they are not rated to 120 watt unless fan cooled apparently. I am trying to build a mini version of the Aleph J and don't want run into problems with power supplies not being capable for the load. I am looking at some PLC power supplies that might be a better choice since they are industrial grade but albeit a little more pricey.
I’ve experimented with it and I can report back very, very good results with SMPS and a post filter that Mark Johnson has been working on. Good enough that I doubt that my next amp will be powered by a linear, because there seems to be no discernible sound quality difference between it and smps in what I have observed so far. This, combined with significantly less magnetic radiation in the chassis, no possibility of a humming transformer, and less overall mass, has me very interested in pursuing this path further.
As for “significant improvement” on ACA and Vfet, my observations of the same do not lead me to change my opinion in much way one direction or another.
I have not tried a bucket of capacitance on the output of a larger SMPS. Properly computed CLC is where my experiments have gone and it works very, very well.
As for “significant improvement” on ACA and Vfet, my observations of the same do not lead me to change my opinion in much way one direction or another.
I have not tried a bucket of capacitance on the output of a larger SMPS. Properly computed CLC is where my experiments have gone and it works very, very well.
Impedance Graph
Eric, taking another look at that graph (and the legend below), it appears that you were correct. Sorry about that!
Eric, taking another look at that graph (and the legend below), it appears that you were correct. Sorry about that!
I've recently sent fully populated & tested SMPS filter PCBs out to Alpha testers, to drop into their VFET amps and listen critically. The boards include magnetic components (inductors etc) by Bourns and Laird, and super low ESR electrolytic capacitors by Panasonic: series EEU-FM. I've been very pleased with the sonic performance and lab measurements, but we'll see what disinterested third parties have to say.
(These new boards also include a thump prevention relay, with PCB jumper selectable muting time. Thumps seem to be a hot button issue with a small but vocal minority of members).
(These new boards also include a thump prevention relay, with PCB jumper selectable muting time. Thumps seem to be a hot button issue with a small but vocal minority of members).
If I were to build an Aleph J with SMPS, I would take the following approach:
1) Must be capable of supplying +/– 24V at 6 Amps or greater per rail. Best when done with a dual-rail PSU to avoid having to 'stack' a pair of switching supplies to get positive and negative rails.
2) Always, always independent power for each channel. The Aleph J deserves no less. The ACA needs it, the VFET amp needs it and the Aleph J needs it. This not only helps stereo imaging, but also helps with micro dynamics.
3) Apply about 30 mF of capacitance to each power rail.
1) Must be capable of supplying +/– 24V at 6 Amps or greater per rail. Best when done with a dual-rail PSU to avoid having to 'stack' a pair of switching supplies to get positive and negative rails.
2) Always, always independent power for each channel. The Aleph J deserves no less. The ACA needs it, the VFET amp needs it and the Aleph J needs it. This not only helps stereo imaging, but also helps with micro dynamics.
3) Apply about 30 mF of capacitance to each power rail.
Aside from good reliability, medical grade SMPS are designed primarily to avoid electrical shock to a patient when they are in contact with a medical device. The regulatory testing and approval add a lot of extra cost to these units. Doesn't really help with audio performance.
For audio performance, there is a need to supply higher level, steady-state current. And to be able to start up into higher external capacitance. Check out the Micro-Audio products.
For audio performance, there is a need to supply higher level, steady-state current. And to be able to start up into higher external capacitance. Check out the Micro-Audio products.
Far behind. But finally dismantled my BA-3 today, saving the boards for later tinkering and upgrades.
Seen here don’t look like much, and probably aint much, but managed to fasten the rubber feet through the bottom plate and heatsink frame by drilling the holes larger. Also included is ZM style spacers which I managed to mount using a star M3 screw into the sunk in hole - so that the screws are clear of the bottom plates. Spacers are standard China stuff, and a washer helps stabilize it.
Slooowly, but steady.
No boards arrived yet, but the PCB spacers have found their place in the sinks, Poseidonsvoice style, which happened to be my plan too.
Andy
Seen here don’t look like much, and probably aint much, but managed to fasten the rubber feet through the bottom plate and heatsink frame by drilling the holes larger. Also included is ZM style spacers which I managed to mount using a star M3 screw into the sunk in hole - so that the screws are clear of the bottom plates. Spacers are standard China stuff, and a washer helps stabilize it.
Slooowly, but steady.
No boards arrived yet, but the PCB spacers have found their place in the sinks, Poseidonsvoice style, which happened to be my plan too.
Andy
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