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Old 6th July 2003, 10:23 PM   #31
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The only problem is that the time to thoroughly think out how to build a device takes more time than building the darn thing itself

Well, in my case it does, the hunt for precision and careful design takes its toll.

And then the endless process of tweaking only has to begin....
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Old 6th July 2003, 10:29 PM   #32
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I think this is the case for everybody, if a good product is considered.
Also, during the process of building the first one, I already know how the second one can be improved. Third one is usually harder to improve
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Old 6th July 2003, 10:31 PM   #33
jcarr is offline jcarr  United States
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Dear Andy:

>Do you have any views w.r.t. the ferrous / non-ferrous state of components / leads.<

It appears that to find specific numbers on resistors, I will have to dig very deep. OTOH, I did locate some notes on the distortion added by speaker terminals equipped with gold-plated steel O-lugs, as opposed to speaker terminals that had no such ferromagnetic subcomponent.

The base measurements were conducted at a level of 10V rms into an 8-ohm load, and the power amp that served as a test bed had a residual distortion of 0.00014% under these conditions.

With the gold-plated steel lugs at the power amp output, the distortion rose to 0.0018%, and the added distortion products appeared to consist primarily of 3rd-order harmonics, but higher-order distortion products could also be observed. When the load impedance was reduced to 4 ohms, the distortion increased to 0.0098%.

OTOH, we should not forget that Nichrome - the resistive material used for most metal-film resistors (including Vishays) - is a ferromagnetic material.

FWIW, jonathan carr
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Old 7th July 2003, 08:53 PM   #34
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Hi,

Jonathan,

Quote:
OTOH, we should not forget that Nichrome - the resistive material used for most metal-film resistors (including Vishays) - is a ferromagnetic material.
While this is certainly true, I somehow doubt you would encourage people to use resistors with ferrous endcaps and leadout wires, would you?

If we'd agree (hypothetically) that ferrous content in components, cable, etc. is best avoided then I can start to understand why some people have a preference for oldfashioned carbon composition resistors...even if it means sacrificing a little on noise and reliability in the process.

This seems to be fashionable amongst SE/Tube lovers lately and in the context of digital harshness I can certainly understand why, even if it deviates from neutral.

Are there alternative components you can recommend?


Cheers,
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Old 7th July 2003, 09:00 PM   #35
ALW is offline ALW  United Kingdom
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Jonathan,

Thanks once again for a very enlightening and thought-provoking reply.

I feel I should apply a little more science to this process myself, to see if I can actually resolve in measurement the things I hear with my ears - I'm not sure if my limited test apparatus is up to it though...

Cheers,

Andy.
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Old 9th July 2003, 02:05 AM   #36
jcarr is offline jcarr  United States
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Dear Frank:

>I somehow doubt you would encourage people to use resistors with ferrous endcaps and leadout wires, would you?<

Depends on whether resistors with non-ferrous endcaps and leads are readily available in the values and sizes required. It also depends on other important parameters like value accuracy, noise, inductance, hygroscopics, tempco, and so on. Even when I observe something concrete, like the distortion imparted by ferrous construction, I try to keep everything in perspective, and maintain some idea as to the relative ranking of the various evils. And if this requires me to sometimes act as my own Devil's Advocate, so be it.

BTW, I should note that the DUT (gold-plated steel lug) was added at the power amplifier output, and so was not included in any sort of NFB loop. If it were placed inside a global NFB loop, I would expect the measured distortion to drop substantially. OTOH, normally, 3rd-order distortion products tend to increase by the square of the voltage or current applied (current in this case, going from an 8-ohm load to a 4-ohm load), But what was observed was an increase in distortion from 0.0018% to 0.0098%, which exceeded the expected four-fold increase.

>If we'd agree that ferrous content in components, cable, etc. is best avoided then I can start to understand why some people have a preference for oldfashioned carbon composition resistors.<

I will add that carbon comp resistors usually have no spiral trimming, with relatively low inductance per unit length as a result. Of course, the lack of trimming is part of the reason why their values are all over the map,

>even if it means sacrificing a little on noise and reliability in the process.<

And the fact that carbon comp resistors are usually rather hygroscopic, meaning that they can change value depending on a combination of the atmospheric humidity and operating temperature.

>This seems to be fashionable amongst SE/Tube lovers lately and in the context of digital harshness I can certainly understand why, even if it deviates from neutral.<

Based on how a lot of solid-state gear and also some tube amplification seems to sound, I can also understand why some audiophiles would feel this way, even though I personally don't share their views.

>Are there alternative components you can recommend?<

Admittedly there are certain components that I dislike less than most, but that is about as far as my enthusiasm is willing to extend.

hth, jonathan carr
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