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layout help

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I have 3 ASC polypro in metal cans. 1 is a cap filter. and the other 2 are coupling cap.

Since space is limited on the top of the chassis, I am thinking on mounting them 1cm apart. the fitler cap would be around 1.5cm to 2cm away from the PSU choke.

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I also have 4 tubes which would be part of the power supply (tube regulation as found in rdh 14 chap 33).

  • The 5u4g would be around 2cm away from the power transformer chassis.
  • The 6AS7G would be 2cm away from the 5u4G.
  • The 6sl7 and 5651 would form a triangle together with the 6AS7G and would be around 2cm away from the 6AS7G.

The measurements are not for the base but for the glass enveloped since the 5U4G and 6AS7G are ST shaped.
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The ASC caps would be around 5 to 6cm away from the glass envelop of the 5U4G and 6AS7G.

Thank you for the help.
 
You know... I have seen tube data sheets that listed values for spacing. I looked around a bit... of course, I couldn't find diddly.

2 cm gap seems a wee bit small especially for those monster STs. Could you open it up a bit? Say like 3 cm? Tubes lose their heat in all three ways; some conduction, mostly convection and radiation. A little more distance would help on the last 2.

I did find this link though...

:)
 
In Morgan Jones book, it's mentioned dealing such issue with adjusting the orientation of plates to proper directions. Turning the biggest area facing empty space (or which can sustain the heat).

So the heat radiations from big tubes can minimize their interferences & effects on other component (like caps).
 
CLS said:
In Morgan Jones book, it's mentioned dealing such issue with adjusting the orientation of plates to proper directions. Turning the biggest area facing empty space (or which can sustain the heat).


could you explain "turning the biggest area"?

My impression is that you meant:

the plates must be perpendicular to the caps so that only a small portion of the plate is facing the caps. is this correct?

thank you
 
I have built power supplies with ACS run caps as filters. I have put them very physically close to each other and to the choke (but they were well away from the PTX). The amps were dead quiet, no hum even with my ear inches from the speaker.

I would guess I had 2 cm between the first cap and the choke, and about 1 cm between caps.

I didn't use the ASC caps as coupling caps so I can't comment on that part of your layout.
 
Jarthel,

As far as the caps are concerned... yes, they can be mounted very close as they won't be producing much heat.

You did mention some coupling caps... these should be placed as near as possible, between that is, the circuits they are coupling.

Start with a schematic last has a clean layout, then your physical layout should mirror in some way your schematic... This will lead to each conductor being as short as possible. Don't fall into a "big things on this side" mentality.

:)
 
poobah said:
... Don't fall into a "big things on this side" mentality.

:)

Great advice Poobah. Though I have to admit it took me a while to be able to "see" the physical layout from a schematic. Sometimes with more complex things I still struggle to optimize but a nice clean schematic is the best place to start.

A related note- One mentality worth falling into (most of the time) is "noisy things on this side". :D Though often that "rule" can be bent quite a bit before bad things happen.
 
You betcha!

A clean schematic helps lead to a clean layout. It's not about the exceptions though... more about the possibilities.

You know a good thing to do is work with "puppets". Cut out shapes of paper the same size as your components. Rearrange them on life size paper copy of your chassis. Then sketch in your resitors and all. Takes a little while... yes. But the idea is make your mistakes on the paper and not on the parts/metal!

(I'm cheap AND lazy)



:)
 
That's how I laid out my monoblocks. I made paper boxes the size of the trafos and rolls of paper the size of the tubes and kept rearranging them on the aluminum top plates I chose. It worked well and since I'm a visual person anyway some ideas I originally had could be ruled out before everything was placed.
 
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