Generic poweramp power supply questions

[albertNL]

I am new to this and have spent the last few months reading manuals and postings. I have a few questions about power supplies in power amps.

Aleph service manuals show (for as far as I can make out) only capacitors between bridge and amp circuit.

KK PCB Design uses a CLC design:
ALEPH 3 POWER SUPPLY

In the F4, F5, BA-1 and BA-2 manuals a CRC design is shown.

Why the different approaches?

[alazira]

Although CLC is generally better than CRC, a properly sized inductor would need to be quite hefty and thus much more expensive.

[AudioSan]

Originally Posted by albertNL

I am new to this and have spent the last few months reading manuals and postings. I have a few questions about power supplies in power amps.

Aleph service manuals show (for as far as I can make out) only capacitors between bridge and amp circuit.

KK PCB Design uses a CLC design:
ALEPH 3 POWER SUPPLY

In the F4, F5, BA-1 and BA-2 manuals a CRC design is shown.

Why the different approaches?

CRC is used becuse of its price. and one thing is left out on the KK-PCB circuit. the bleeder resistors in paralell with the capacitors.

[tiefbassuebertr]

Instead coils (inductors) and resistors I have often observe rectifier diodes in older diy projects. What are the pros and cons by use of an diode on this place?

[Zen Mod]

supposedly to cur ripple in half

[Atilla]

My guess is ... it doesn't really work that well?

[Zen Mod]

good supply must have bi-directional nature

[albertNL]

Sorry guys, I am still confused.
The power supplies in the original Aleph amps (according to the service manuals) used only capacitors.
I cannot imagine that the cost of the inductors was the reason they were omitted because I cannot imagine Nelson using expensive "heatsink cases" for these commercial products but then not spending a bit extra for sound-improving inductors. So why did Nelson use C only instead of CLC (or CRC for that matter)?

[Atilla]

There's no harm in using only capacitors, especially when they're generously sized. If the amp's PSRR is good enough, there might not be a need to overdo the PSU. I've no idea what the supply of the Alephs is, but I guess it was thought trough, sufficiently.

[albertNL]

Originally Posted by Atilla

There's no harm in using only capacitors, especially when they're generously sized. If the amp's PSRR is good enough, there might not be a need to overdo the PSU. I've no idea what the supply of the Alephs is, but I guess it was thought trough, sufficiently.

Thanks for that Atilla. I know the original Aleph 3 sounds great (I own one) but it is interesting to see that KK PCB Design used CLC in the Aleph power supplies and Nelson uses C in the Alephs and CRC in the F4/5/BA-1/2.

The original Aleph 3 had 8 x 22000uF and 25V rails.
The Aleph 30 had 2 x 6 x 10000uF and 26V rails.
I do not think the 1V difference on the rails is an issue.

In the Aleph 30 manual, Nelson wrote:

The power supply has been improved with half-again more power supply capacitors with twice the voltage ratings, giving lower ESR figures.

I understand the increase in the number of caps: From 8 to 12. I also understand that the higher voltage rating would be beneficial. What is difficult to get my head around is that the total capacitance was reduced from 176000 to 120000. Could this just be because the parts were that much better that less "nominal" capacitance was needed?

Please understand I am new to this. I have worked in IT for the last 30 years where everything is much easier to understand than this analog world! I am trying to understand how and why these analog things work the way they do. In order to do that I am trying to find patterns or rules. For power supply caps I have come up with:
a) higher voltage rating = good
b) better quality caps = good
c) more caps is better than few caps (I know, not always but I assume that if you used caps from the same manufacturer/series you would you would rather use 8 x 10000uF than 2 x 40000uF)

Perhaps my question can be rephrased:
How do you design a power supply? Is it just a matter of trial-and-error and with a lot of experience you'll get a reasonable choice the first time and take it from there (artistry) or is there a more (dare I say) scientific approach?