Power supply ripple

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pre65
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#1 Power supply ripple

Post by pre65 »

Hi-for my "Doddington" ECL82 amp i am going to use a pair of 6D22S damper diodes (like Andrew I).

If i use a shottky diode in series with each one (AFTER) is it likely to make a noticable difference to the ripple ?

If not why not ?
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Nick
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#2

Post by Nick »

Well, to turn the question round, why would it?
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pre65
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#3

Post by pre65 »

Hi-the diode passes only the positive cycle of the AC wave,but ripple is a small AC component of the DC created.

So would another diode not remove the negative aspect of the ripple,making it less ?
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Nick
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#4

Post by Nick »

But after each diode, you have half of a sine wave, adding one or more diodes won't alter that. It might have some effect on the switching noise, but I can't see how it would affect ripple.
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#5

Post by pre65 »

Hi-so the ripple is a positive only component !

Right,i understand now.
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#6

Post by Andrew »

Then you have the extra voltage drop across the solid state diodes, OK only a few volts but it will still be there.

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#7

Post by Nick »

Hi-so the ripple is a positive only component !
Not entirly, its AC, so has positive and negative parts, but as its superimposed on a much bigger DC component its effectivly all +ve (or -ve, depending what you call 0)
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andrew Ivimey
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#8

Post by andrew Ivimey »

Philip, go to nutshellhifi.com, Lynne Olsen's website and have a long read.... the sort of website that needs taking to the bath with a few cooling drinks.

Olsen's discussions mainly cetnre on transformer coupled push pull amplifier design. But he also discusses why damper diodes are the finest recifiers bar none this side of proxima centauri. They are much faster than any other rectifier, drop only a few volts and are very cheap.

I used them because I've bought a few for my 'Amity' project and apart from two arriving broken from Ukraine and one going down on the journey to out last meet, I am otherwise very happy with them.

I am also crackers ennough to have 866, 872, 5U8C, 83(in use in 300b amp) and 6X4 type rectumfriars just waiting for their chances to be used.

GZ34s may be marvellous but ....

Style friend ... !
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pre65
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#9

Post by pre65 »

Hi-i have ordered 8 of the super diodes,4 for the amp and 4 spare.

Came to £23.59 in all.
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#10

Post by pre65 »

Hi-i was reading an article about power supplies (cant remember where) and it was saying the choke and 2nd cap were where the power reserve was,particularly the choke.

But it did not explain how/why the choke was a "resevoir" !

Is their a maxim regarding choke size in a power supply ?

For example,in my doddington ECL82 power supplies (dual mono) what is likely to be the practical difference between a 10h choke and a 30h choke ?
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#11

Post by Nick »

But it did not explain how/why the choke was a "resevoir" !
A choke will store energy as electromagnetic flux in its core. A choke with tray and maintain a constamt current flow. In the same way as a cap will store energy in the form of electrostatic charge between its plates, and try and maintain constant voltage.

Simple put, this is the point where knowing some basic theory is usefull.

You can imperically explore the difference using PSDII
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