Electronic filter.

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pre65
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Electronic filter.

Post by pre65 » Thu Mar 16, 2017 8:55 am

Saw this on Ebay just now.

Is it similar to the E-choke Mike H used to do ?

http://www.ebay.co.uk/itm/Tube-Preamp-A ... 1660715763
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Michael L
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Re: Electronic filter.

Post by Michael L » Thu Mar 16, 2017 9:21 am

I was talking to MJ last Owston meet up about the pros and cons of such a circuit compared with a filter using a choke.
I admit I didn't fully understand - well I had consumed some beers.
Could someone enlighten me?

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Nick
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Re: Electronic filter.

Post by Nick » Thu Mar 16, 2017 9:38 am

The circuit it there, its a cap multiplier

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Mike H
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Re: Electronic filter.

Post by Mike H » Thu Mar 16, 2017 12:12 pm

Yes virtually identical to mine.

Which Nick G helped me with incidentally. :D
 
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Re: Electronic filter.

Post by Michael L » Fri Mar 17, 2017 8:34 am

Michael L wrote:
Thu Mar 16, 2017 9:21 am
I was talking to MJ last Owston meet up about the pros and cons of such a circuit compared with a filter using a choke.
I admit I didn't fully understand - well I had consumed some beers.
Could someone enlighten me?
Still none the wiser. I assume using a choke must have advantages because it's weight and cost are disadvantages.

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Nick
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Re: Electronic filter.

Post by Nick » Fri Mar 17, 2017 8:42 am

The mosfet cap multiplier will filter the DC. A Choke will do that, but will also store energy in its flux which the SS wont do. If a choke is used in choke input, then it has the magic feature of drawing continuous AC current from the transformer.
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Mike H
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Re: Electronic filter.

Post by Mike H » Fri Mar 17, 2017 11:55 am

The electronic version needs an overhead of extra supply Volts, which can be quite awkward to provide. Or in other words, you lose some HT, in my one's case, about 25V minimum. So appreciably less efficient than a genuine inductor choke.
 
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Re: Electronic filter.

Post by Michael L » Fri Mar 17, 2017 1:45 pm

Thanks Nick and Mike.

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Re: Electronic filter.

Post by Colin Wonfor » Sat Mar 18, 2017 6:24 pm

Unitrode did a nice SMPSU in a high speed switcher, using current doubling which allowed us to use smaller caps with chokes, a nice design.
We re-worked it with a full resonant bridge circuit and made it RAD Hard and now they are whizzing over head in space. We also used Si plated in Gold.

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Dave the bass
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Re: Electronic filter.

Post by Dave the bass » Sat Mar 18, 2017 8:26 pm

I had to Google 'RAD Hard'!

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Mike H
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Re: Electronic filter.

Post by Mike H » Sun Mar 19, 2017 12:42 pm

Wow .. :shock:
 
"The beer was so flat it could have been served in an envelope...."

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