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DC Blocker GB closing soon

So, now the DCT03 filter is going to form part of my mains filtering, I'm thinking about common mode noise rejection next and if its worth investigation.
Currently looking at this:http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=133176216934
I'm planning on making a; 1-inlet to 4-way outlet DC/Common mode filter, and was wondering if the 20A Common mode noise filter in the link above will be sufficient to use on a pair of outlets or should i use 1 per outlet?

Thoughts on the above?
 
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Mynamemynaim said:
So about £100 build all in give or take a case for it...so is the group buy for the parts for the board closed now or not please?
Click to expand...
The GB I ran was really a spur of the moment thing and was driven by getting enough people to hit the multiple that got a big discount on the caps. I’d have needed twice as many to have been able to order more.

That said I’ve got two boards and two sets of components myself and I’m now wondering if I’ll only need one. Give me a day or two to ponder and I’ll let you know if the second set is surplus to requirements.
 
paulski said:
The GB I ran was really a spur of the moment thing and was driven by getting enough people to hit the multiple that got a big discount on the caps. I’d have needed twice as many to have been able to order more.

That said I’ve got two boards and two sets of components myself and I’m now wondering if I’ll only need one. Give me a day or two to ponder and I’ll let you know if the second set is surplus to requirements.
Click to expand...

Thanks... could well be interested!!
 
Sorry if this is a stupid question, but what is the solution for enclosing the circuit board and adding appropriate connections?
 
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@Cereal Killer, so you have Per's DC blocker PCB and you've added common mode filters? Just trying to understand exactly what components I need to complete a DC blocker as I am somewhat confused right now!
 
Thats looks like a good layout and just what I had in mind.
I haven't read anything on the C/M filters yet?
Do you have any technical info on the values of the components that are needed for them.

Alan
 
Thanks Si just did that but those boards are not the same as the ones I have ordered off E-Bay so will wait for the schematic
I have ordered some 20A Bourns Common mode choke's and some epcos 0.47 X2 caps

Alan
 
Alan the fofelix ones will be better, snubbers designed for each coil type specifically, and with measurements showing elimination of ringing. The original Folsom boards from diy look the same as the current ebay ones.
 
Is it measurement, or is it just simulation, as it strongly appears from the links I've found (recently, and in the past) ..?
CMC - based filters are interesting, perhaps even useful: but you get wildly different answers depending on how you model the things..and esp what are assumed for supply and load impedances.

And real AC mains is ..nothing like the above; nor are most AC-input loads..!

CMCs have both CM and a much smaller effective 'leakage' of differential impedance due to practical imbalance in winding / physical geometry - so once real-world capacitances are added, the maths and reality gets messy.

<looks at 25A CM choke still being played-with.../>


(oh, and adding damping across the CMC is a very old trick: even for 'hifi ' use. Lynwood for one did this at least 3 decades ago - as I found out when I measured a plugtop thing I found for pennies in a junk sale. Iirc, LesW had a hand in that ...)

PPS
I really, really don't like Y-caps in mains filters close to the kit for audio.
They never help in audio that I've played with; they're added-in thoughtlessly on the basis of putative 'symmetry' but since AC Mains is unbalanced, what they really do is add a leaky noise current route from phase live, that becomes a noisy voltage once poured into the real impedance of the Mains Earth locally. Depending on how your system is wired, that can be anywhere from 'some' to 'very' unhelpful.
tl;dr: if you want to add common-mode filtering - build/try something, just omit the Y-caps: ie build it as a true common-mode filter that only involves Live and Neutral.
Try that a while.
Then add the small-value Y-caps in.
(I bet you'll remove them to try again...)
 
I've got a couple of DCT03 boards on the way. As well as offset, we've got mains that averages 253V so I'm thinking of adding a bucking traffo into the mix.
Worth doing? (amp is SS, no valves to over-cook). If so, before or after the DC blocker?
 
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