Copper Busbars in Aleph-X power supply

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Hi All,

I am planning the Power Supply in my upcoming Aleph-X project, and came across a dilemma. I own some lengths of heavy duty copper busbar, approx 40mm x 6mm cross section, which I have been saving for this project. I want to use them to move the Power supply currents around, from the rectifers to the filter caps to the output transistors. After all, it is widely accepted that this is a very good way of doing things, a lot of great amplifiers do this, or something similar (eg Pass Labs X series, Merk Levinson etc.)
However, in the XA200 amplifier, and therefore in my upcoming Aleph-X, it has a CRCRC filter, with the R's approx. 0.06 ohms. (From the XA200 8amp bias, with around 1volt drop across the R's, Anyway numbers aren't important in this question).
My question is, is it worthwhile using these massive copper busbars with ultra low resistance, if I'm going to insert a (relatively) high resistance in the circuit. Wouldn't I be better off using relatively small wiring, that simply handles the bias current?


Adrian
 
I would say that doing something like this AFTER filter caps is probably worthwhile, but i you don't need the thickness you are referring to. I have done somthing similar using sheets of Cu right on top of one another (with appropriate holes and spacers) to get ultra-low impedance to the load. The setup is 9 units of capactitors (phase to phase in my situation), and the sheets are about 15*15cm. I think this would be fairly ideal.

The problem with bus-bars is - how do you connect to them reliably and with low impedance? I guess you could put all the caps in a line and just screw right through them - but I am pretty sure that won't get you as far as the sheets.

It would look cool. though!

Back to your question: After caps you should have low impedance. Before caps, it does not really matter all that much. Some inductance (or indeed some of your resistance) will probably do more good than harm.

Petter
 
it may look cool -- but if it's accessible you may want to put some heat shrink tubing on the copper so someone doesn't use it as a handle.

the big Trygon (2kW) supplies I have use copper bar, copper braid and copper straps -- even looks as if they used some copper roofing sheathing, here's an example:
 

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I veemently disagree with the last post. There are a number of issues due to the high currents of the X circuit for which Cu bar are just about perfect, I won't go into details right now, build an AX and you will see. 6mm Cu bars maybe a little excessive but they do wonders for the grounds, whether you use single or dual rectifier bridge. I thought I was overdoing it but it ended up being just right. You can pretty easily engineer a way to use them for the +\- rails as well with the thermistor.
If you are going to use screw type capacitors you are probably going to need longer screws.
 
curious newbie question: what is the consensus about fusing? Do we figure that the line fuse will take care of us if there is a failure? Obviously, fuses in the supply side would make nice heavy buss bars seem sort of silly. Is there an audiophile acceptable fuse?
 
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