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In the Forum: Melquiades Amplifier
In the Thread: 6 Channel Version of Super Melquiades
Post Subject: Power supply with less is more.Posted by Romy the Cat on: 12/25/2007

 hagtech wrote:
It's difficult for me to guess exactly what the possible sonic effects of the ripples would be.  I see a tube operating at a fixed point, having a particular distortion spectrum.  Say -42dB 2nd harmonic.  Then, the ripple pushes it to a new operating point, giving -40dB 2nd harmonic.  So the treble signal is modulated where distortion fingerprint changes at a 120Hz rate.  Is that audible?  What does it sound like?  Maybe I am chasing ghosts.

Similarly, we have the same thing with DHT, as the operating point of tube changes with the temperature of the cathode, heating and cooling at 60Hz. 

Maybe this is so far down in the noise floor we cannot hear it yet.  There are other peels to the onion that must be removed first.

Jim, I do not think that it is the question. There is no argument that “no ripples at all” is better than ripples and no one argue that sonic effects of the ripples, no meter what it would be, is altogether negative. However, there is also a negative effect of the mechanism that minimizes ripples – the capacitance.  So, the quest is where the negative impact of ripples would be “competing” with the negative impact of the capacitance. Perhaps you took me too literary what I said about that “ripples do not meter”. So far in Super Milq I use huge a huge amount of capacitance with having absolutely microscopic amount of ripples – I would like to revise it for the HF one-stage amps. Not the least reason, and perhaps the main reason, is because, as I said before “larger capacitance makes HF harder”. Actually I even being to question if I even need a second cap in amplifier itself. In all my 2 chassis units, including the Super Milq I have the LC with a bleeder in PS and then RC in control unit. I usually try to keep the last cap as close to load providing the shortest DC path to ground. If I keep the last cap of small value on the PS side then I lose bass and Dynamics. Now, I wonder if I need to worry about it in context of HF one-stage amps. It might be that I will be go away with just one single LC on PS side with a small cap of very good quality (not metalized). I might be interesting if it turn out to be true… It always will be easy to add the second cap on the amp side to short the ground locally… BTW, since it will be effectively a high-pass filter and since I do not do LF it one-stage amps then might be a very small cap, perhaps the Teflon values…

I am trying to think about this power supply from a perspective that less is better.

The Cat

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