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Re: pseudo C input

Hey,

No No No !! NEVER do you ever wanna put ANY cap as the input filter in a filter chain..." even an einsiee weinsie tiny one ". It puts spikes on de B+.

Use a low HY L as the input filter - always. This L does not, and actually should not, meet critical inductance. Use an L input - JUST to control the diodes some and strip off RF as Dennis Fraker has CLEVERLY figured out to do !!

Too large a HY and you slow down the supply. John Swenson has gone from 120 ms to 8 ms with his Dennis Fraker - like implementation. I would suggest, for example, in addition to the Signal Transformer DU 1/2, using something like the Triad C-40X for a starting L. Its 10 ohms DCR, .32 HY and 600 mA rated .... and under twelve dollars. Can you handle that cost, if not, I know of one for $9.49, similar specs. Figure your final B+ VDC value will equal 1.35 times the VAC of the secondary's VAC , MINUS the drop of your rectifier.

Now please listen, on a Signal DU 1/2, its entire secondary, both 120 volt windings connected in series, measures ONLY 1.72 ohms on my Fluke 8060A!!!!!!!!!!!!!!!!!!!!!!!!!!! ULTRA hi fi terrritory !!! Where in the hell are YOU gonna easily find a power trannie with 1.72 ohms DCR across its entire secondary ??

Do you think that such a power transformer will give you some NATURAL deep bass and true INNER DEFINITION and a FLOW of the music. I sure do !! Hey, hey, its got four windings, two on each side, with taps that are 104, 110, and 120 VAC on EACH winding, so you can CHOOSE and TRIM your primary and secondary AC voltages. Wake up and smell the roses, the Signal Transformer DU1/2, a part I originally I suggested for John Swenson to "try" and ocassionally use myself, WILL work well for others, and its an industrial part too.

But as soon as you slap a larger than one HY L, with over ten ohms DCR , and a C larger than 50 uF, you will have LOST the essence of this design... and de music. Have fun.

They are listening to this type of supply in the Galibier Design Suite ( 1130 ) Sunday at RMAF as I type this, on Azzolina Audio horns ( 103 ? dB ) , and I heard it there late in the day on Saturday, via Dennis' SE 2A3 amp, and it sounded awfully good to me, and all present. Of course, Dennis ' amp is a TOTAL design, of which. this power supply topic is only PART of the story. All the other SE amp design basics were covered previously on this forum by DF and I, under my Forum posts.

Jeff Medwin

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