Top resistors


Many threads with opinions on boutique coupling capacitors, but very little consolidated information on the sonics of resistors. Anyone care to share their thoughts on the attributes of their favorite brands & types for specific tube and SS applications? How much of a difference does a good resistor make?

My interest in the topic increased after recently installing the latest Texas Components nude Vishay TX2575 in several SS and tube phono & LS components. This was a proverbial "Ah-ha" moment-- a stray resistor dropped into signal path here or there, surprising with an improvement that equalled or surpassed the impact of a switch to a top coupling cap like V-Cap or Mundorf.
dgarretson
OOPS- Make that Ohno CONTINUOUS Casting. BTW: I'll bet that the Bulk Foil and Nude Vishays, or Caddock Precision Films, would not show as dramatic a directionality, if at all.
Could this also account for the "directionality" in fuses some claim to hear? Any idea if the HiFi Tuning fuses are [P]OCC or not?
Regarding the oscilloscope waveforms shown at the link Eherdian provided, I'm not sure how they prove anything about anything.

It seems to me that the differences shown for the two orientations mainly involve interplay between the following factors:

1)The difference between the impedance between his fingers and one end of the resistor, and the impedance between his fingers and the other end of the resistor. Each of those impedances being comprised mainly of capacitive coupling between his fingers and the resistive element, plus some fraction of the total resistance of that element.

2)The impedance of the leakage path between the probe's ground and the scope's AC power input. Note that the time scale on the scope is 10 ms/division, from which it can be seen that the "signal" is comprised mainly of 50 Hz (he is evidently in a 50 Hz rather than 60 Hz country).

3)The input impedance of the scope/probe combination (i.e., the impedance that is seen "looking into" the tip of the probe, relative to its ground).

4)The relation between the value of the resistor and the input impedance of the scope/probe combination.

5)The impedance from his fingers through his body and through any path that may exist from there to AC/earth ground.

I see no reason to expect the net result of all of that to be equal for the two orientations, regardless of whether or not the resistor would have directional characteristics when inserted into a circuit. That conclusion would be true even if he managed to grasp the resistor exactly at its mid-point, due to the differences in AC leakage to the probe's ground and its tip.

BTW, although I haven't taken the time to read a lot of the posts in this thread, I happened to notice the one dated 10-22-12 from Larryi. As is almost invariably the case with his posts, it strikes me as being technically plausible, ringing true, and being an important point.

Regards,
-- Al
Maybe the law of averages should be applied. Multiple measurements would mean multiple touches which may provide multiple numbers. Of course all of this would have to occur in the same time frame and with the same physical circumstance. If the numbers recorded on average from end to end were different it would seem to me that there is validity in Larry's method. Tom
Not having experimented with resistor directionality; I have no opinion regarding validity. However: I can't help but notice; in every picture the tester has his fingers on the body of the resistor and not touching either lead. no doubt; it would have been expedient, to have removed himself/his body from the test completely. Testing capacitors for outer foil, has shown me how much influence a body can have regarding induced noise. Why would the impedences of the probes, ground wire, etc not remain constant? According to the script; he was testing for voltage/mV differences. If the results were repeatable, and mostly constant, between resistors of the same value; I'd see no reason to doubt the conclusions he's made.