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RE: Low DCR versus higher inductance chokes

129.123.241.91

In Reply to: RE: Low DCR versus higher inductance chokes posted by xaudiomanx@aol.com on October 05, 2008 at 17:18:44

If you want a straight answer, leave this forum immediately and go to diyaudio.com.
There is a group here that views any DCR to be evil, rather than as a parameter which should be optimized to produce a well-behaved power supply. Think of DCR as the struts in your car's suspension - it provides the damping between the interaction of springs and vehicle mass (inductance and capacitance) as it responds to varying forces (currents). Too low of DCR, and the power supply rings at too high of a quality factor, and can add excessive color to the sound under dynamic load conditions (i.e., in a single-ended amplifier). Just like a car bobbing up and down with leaky struts, responding poorly. A low-DCR power supply for low-current applications might sound "full of life", but it's not necessarily the music you will be listening to. This can, and should, all be optimized via simulation - PSUDII is a good starting point. Too much DCR is a bad thing, but an optimized DCR can be of benefit.
For more information about filter theory for classical mechanical and electrical systems, check out Olson's Dynamic Analogies - one of the best references on this topic, and one of the most brilliant engineering texts I've encountered.
I'm surprised this debate has survived for so long!
BTW - the low-inductance in the LSES supply is something that I cannot take seriously, and is far more controversial than the simple low-DCR fad - it is not reasonable to expect input chokes below critical inductance to properly supply stable B+. A low-DCR power supply with sufficient L will perform well. The LSES as I've seen it described looks more like a bad cap-input supply with added resonances than it does a proper LCLC filter. I would not be willing to invest in building one.

Edits: 10/05/08

Follow Ups:

YeaaaaaBaaabeee! (nt) - wheezer 11:40:04 10/06/08 (0)
Well said (nt) - danlaudionut 18:16:15 10/05/08 (5)
DanL
- RE: Well said - Ray Moth 22:31:21 10/05/08 (4)
  Indeed. It's all very well for people to say that a couple of 320 mH 10 ohm chokes don't cost much, but it isn't just the layout in materials. It's also the investment in time to procure the materials and to make the change and conduct the tests. There's also the nuisance factor due to the intrusion of making the change to an existing amp.
  - 200 to 1 - drlowmu 07:25:25 10/06/08 (3)
    Hi Ray,
    
    Be truthful, you ALL have spent FAR more time over almost two years, writing about this on various Forums, I would estimate 200 to 1, versus the time to breadboard the L/C/L/C supply filter into existing gear and listening!!
    
    Jeff Medwin
    - so what... - PakProtector 08:25:50 10/06/08 (2)
      I don't respond to emails requesting assistance transferring funds from someplace far away either, and they're reasoning is waaaaay better than Dennis' on why LIES works.
      cheers,
      Douglas
      
      Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
      - Douglas - drlowmu 09:29:52 10/06/08 (1)
        
        In Reply to: RE: so what... posted by PakProtector on October 06, 2008 at 08:25:50
        
        Your prejudices and ego is showing, and it doesn't relate at all to what myself and other people hear !!
        
        Jeff
        
        Jeff - PakProtector 09:54:20 10/06/08 (0)
        
        In Reply to: RE: Douglas posted by drlowmu on October 06, 2008 at 09:29:52
        
        It isn't supposed to be in any way related to what you claim to hear.
        
        Are you going to claim there is a single consistent description of this LIES design? ( just to save you the time, that was a rhetorical question, but you should go ahead and show your character by answering it anyway ).
        
        So far you've presented nothing that deserves any attention. 'I hear something', would usually be quite enough, but the piles of manure delivered to requests for more information are about enough to obscure that reasoning. If it were real, it would also be consistent. First it was low DCR( and there was a high inductance, low-mu special designed ), then it was the Flywheel...and as soon as some insight and investigation was brought to bear on that, the design changed again. Not going to go off with some inconsistent design when it is just as troublesome to implement a consistent one.
        
        Get your story straight, maybe it will be worth listening to then.
        cheers,
        Douglas
        
        Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

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