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In Reply to: RE: SET's and Bybees? posted by unclestu on January 09, 2012 at 15:39:43
if they do put current & voltage back in phase, they're basically doing Power Factor Correction.
rowland charges like 1500 for his outboard PFC. but thats AC only.
If they are performing power factor correction after an inductive load, are they basically capacitors? I read somewhere that they do not measure as being capacitive or inductive, which is why it remains a "mystery" (at least in terms of common electrical theory) as to how they work.
NO, NO, NO! The resister used in a large purifier is a .025 ohm resister, but of high wattage. That's right, POINT zero two five ohm, and I have taken one apart to measure ( actually no need to measure as it is printed upon the resister body).
Power factor correctors used on AC lines for large institutions ( hospital, hotels, etc) employ banks of capacitors, but such a system will not work for audio. For an AC line, you are essentially working with a constant voltage. The capacitors delay the voltage. For a 60 or 50 Hz as long as the sine wave of the voltage is aligned with the current, it doesn't matter when the voltage is delayed. For audio, capacitors would actually increase the voltage shift, and since audio is not just one frequency, the result would be problematic, to say the least, unless you use the caps for an AC line only. The time constant for the delay is dependent upon the frequency in audio.
The Bybee purifiers take an arbitrary point for the voltage group delay, and then attempt to speed up the current to match. Here in lies the major difference with the Bybee units. They are not slowing down voltage to merely match the voltage sine wave.
You can investigate more about caps on AC line on the Magnan website. Following his advice, I use motor run caps on the AC lines running then in trios across all three lines. True power factor requires some calculations based upon the current being drawn, but I cheated and simply kept adding caps till there was no sonic improvement.
The Bybees, in my experience, work best after solid state rectifiers. They do NOT work after tube rectifiers, again, because I believe the tube rectifiers have their B+ coming out of the cathode (current source) and thus the current is in phase with the voltage. The Bybee doesn't work after B+ chokes, again because the choke's operation is to current regulate and thus negates the effect of then Bybee.
Hope this helps, and
Of course YMMV.
At the site a set of four cost $5500!
"The Bybee purifiers take an arbitrary point for the voltage group delay, and then attempt to speed up the current to match. Here in lies the major difference with the Bybee units. They are not slowing down voltage to merely match the voltage sine wave. "
So would they work between the coupling capacitor and just before the grid resistor, Note - I already have one on the input signal in the pre stage?
So this would be after the pre and gain stage just before the 300b grid resistor?
I use Bybees at the downstream end of i/c's. To my ears, they seem to clean the grunge and make timbres sound more natural. I think of them as quantum noise sponges. So I imagine that if a coherent wave front comes through, that's fine, but stragglers and lone photons are removed.
And I agree, IMO sometimes one on the positive or on the ground is quite enough, while two (or 3 in an XLR balanced cable) can be too many, resulting in an overdamped sound that is rolled off at both ends.
I use one also on the positive side at the end of my speaker cables. Definitely worthwhile in my experience.
And a very hi ohm one at that....
I should measure the DC resistance of my set. I would never guess that it is a resistor of high value because it does not subjectively appear to reduce the amount of power being delivered to the speaker. But, the tighter sound I heard could be the result of higher impedance reducing the frequency response variation due to the highish output impedance of the amp.
Except that most people do not understand power factor correction.
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