audio-talk

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

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?

The circuit it there, its a cap multiplier

Yes virtually identical to mine.

Which Nick G helped me with incidentally.

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.

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.

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.

Thanks Nick and Mike.

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.

I had to Google 'RAD Hard'!

Respekt!

Wow ..