New build AB763 what resistors

[billyz]

To me the biggest problem with MF and CF resistors is that the cheap and readily available ones all have steel (tin plated) leads and
Internal end caps. This affects the tone and makes for harshness.
I very much like military grade MF like dale and IRC rn series.
Another very good sounding , quiet, one is the PRP brand as well as Takman.
The old AB, Stackpole, IRC CC resistors had tin plated copper leads and brass or copper internal caps.

[murray sanders]

Thanks Billyz
There is a lot to learn about resistors , maybe I'll build a couple of boards with different types of resistors if the first one turns out bad or noisy

[billyz]

New CC resistors are seldom noisy. I find it is cumulative effect , the more of one kind the more I hear it. Some positions are more noticeable than others as has been noted earlier. The capacitors might be even more important. It is the sum total of all the parts and layout. I doubt you'll find bad resistors, it does happen though, measure everyone before. I have had some mismarked ones, usually the cheaper ones( xicon). Many builders are perfectly happy using xicon metal film throughout and sprague 715 caps, alpha pots and classic tone transformers. Does not do it for me , I've played too many vintage amps and my taste buds are spoiled.

[martin manning]

A not-too-scientific test of parts from the resistor bin to look for gross differences at audio frequency and low voltage. If there are any, they don't seem to show up in these basic electrical properties to any significant degree.

[billyz]

A not-too-scientific test of parts from the resistor bin to look for gross differences at audio frequency and low voltage. If there are any, they don't seem to show up in these basic electrical properties to any significant degree.

I will readily concede that what we can measure does not equate with what we can hear and feel. We know there is much debate for what cannot be measured, never the less. Measurements are important , as is the actual experience. Let's include both. We may yet find the truth or more of it.



I did edit this to soften the tone. and to correct the spell checkers.

[martin manning]

A not-too-scientific test of parts from the resistor bin to look for gross differences at audio frequency and low voltage. If there are any, they don't seem to show up in these basic electrical properties to any significant degree.

I will readily concede that what we can measure does not equate with what we can hear and feel. We know there is much debate for what cannot be measured, never the less. Measurements are important , as is the actual experience. Let's include both. We may yet find the truth or more of it.


I did edit this to soften the tone. and to correct the spell checkers.

I don't think you are conceding anything, rather you're suggesting that ordinary measurements cannot explain the nuances in the aural experience, and you are certainly not alone in that belief. The parts listed above are clearly not identical, but the differences in their parasitic properties is minuscule compared to the values typically required to produce an audible difference. I'm not arguing that there is no effect if it isn't predicted by measurements, but if not then the cause of the perceived nuances is something that is simply outside the normal scope of audio circuit design. I can see a lot more room for this sort of thing in capacitors than resistors, FWIW.

[ToneMerc]

A not-too-scientific test of parts from the resistor bin to look for gross differences at audio frequency and low voltage. If there are any, they don't seem to show up in these basic electrical properties to any significant degree.

FWIW, EKC is Electra and the wattage is .5W @ 125 degrees C

TM

[martin manning]

Thanks, TM; fixed it.

[ToneMerc]

Thanks, TM; fixed it.

YW, 10-4

TM

[Zippy]

A not-too-scientific test of parts from the resistor bin to look for gross differences at audio frequency and low voltage. If there are any, they don't seem to show up in these basic electrical properties to any significant degree.

I will readily concede that what we can measure does not equate with what we can hear and feel. We know there is much debate for what cannot be measured, never the less. Measurements are important , as is the actual experience. Let's include both. We may yet find the truth or more of it.


I did edit this to soften the tone. and to correct the spell checkers.

I don't think you are conceding anything, rather you're suggesting that ordinary measurements cannot explain the nuances in the aural experience, and you are certainly not alone in that belief. The parts listed above are clearly not identical, but the differences in their parasitic properties is minuscule compared to the values typically required to produce an audible difference. I'm not arguing that there is no effect if it isn't predicted by measurements, but if not then the cause of the perceived nuances is something that is simply outside the normal scope of audio circuit design. I can see a lot more room for this sort of thing in capacitors than resistors, FWIW.

In the FWIW column: If you replace old CC resistors that are making noise, I doubt that you'll measure any characteristics that show them to be defective.

[martin manning]

In the FWIW column: If you replace old CC resistors that are making noise, I doubt that you'll measure any characteristics that show them to be defective.

Ah, but you can measure the noise if you want to, and judge them to be defective against some specification. That is just an issue of the material used or the degradation thereof, and the causes of noise in resistors is well understood.

[Zippy]

In the FWIW column: If you replace old CC resistors that are making noise, I doubt that you'll measure any characteristics that show them to be defective.

Ah, but you can measure the noise if you want to, and judge them to be defective against some specification. That is just an issue of the material used or the degradation thereof, and the causes of noise in resistors is well understood.

Agreed, Martin. I'm simply saying that if you pulled the parts from a bin, you wouldn't know until they were in the circuit, that they were "bad". The degradation isn't measurable by low DC voltage measurements (VOM, etc.).

[martin manning]

My point is that if someone is interested in testing for noise it can be done, and component selections could be made accordingly. Claims made about the superiority of one resistor or capacitor brand over another, or new vs. old, are often in very subjective terms like "smoothness" or the like. No one that I know of knows how to test for that, but one might suspect that since parasitic properties like inductance, capacitance, ESR, etc. can have an effect on audio frequency response, one might look there. Measuring those properties doesn't seem to be very revealing, however. I've seen several extensive investigations into the harmonic distortion produced by capacitors, and that can be measured, but it seems to rapidly become a numbers game where the differences seem far too small to be detected by human ears.

[Firestorm]

R. G. Keen wrote an article in 2002 showing different carbon comp resistors' voltage coefficient of resistance and concluding that with a large voltage across the resistor and signal swing that was a significant fraction of that voltage, the carbon comps would distort the signal to produce audible 2nd harmonic distortion. The downside is that the beloved CCs of the fifties were manufactured to looser tolerances and modern manufacturers would likely reject any that exhibited too much of this effect.

[billyz]

I am in no way saying one is better in terms of construction method. It is probably the technically inferior or older design is just more pleasing to my ears, not that it is superior in all qualities . I do find in general the steel ( tin plated) leads inferior on several fronts. they are more brittle and break easier and I believe they contribute to the harsher tone I hear.
It is a fact that most modern resistors and capacitor are much tighter in tolerance than the older "Vintage" ones.

I think of it in terms of older instruments using old growth wood compared to new fast grown wood. the old instruments had more variability than modern ones , but there is no denying the tone qualities of a vintage instrument. Yes, there were some stinkers then , probably more than today.