Scott said carbon film vs metal film. Not carbon composition. Carbon film will have second and third harmonic distortion. Carbon composition resistors vary much more and some will show distortion not just àt a much higher level but lots more harmonics.
Used at low power levels carbon film are still worse than metal film, but nowhere near what carbon composition resistors produce.
Now as real life humor on one thread here someone listed his carbon composition resistors in his order of preference. It quite accurately listed them in order of highest distortion to lowest. He even noted two brands that sounded quite close and again when I first measured both I thought one might be a relabel of the other until I noticed a small diference in one of the higher harmonics. My suspicion is they both get their coal (carbon) from the same source.
At line levels there is no appreciable power and as I said I hear no difference at all. How many time do I have to say it I DON'T hear any difference. If anyone wants to put themselves in the position of "I don't know" be my guest, amazing actually it's been years no takers.
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We really don't communicate! I am agreeing with you! Although folks may claim to hear second or third order distortion at low levels (-60 dB or lower) there ain't much research to show that.
When differences are perceived at vey low levels of harmonic distortion my experience is that there is another issue. Usually items such as clipping and bad recovery artifacts.
As you are well aware we can measure things to almost silly levels. The skill is knowing what to measure. As I have stated my goal is -160 dB. Don't expect to reach it, but I strongly suspect at that level the electronics are truly transparent.
Carbon film too. I just listed CC because that would be easier to hear when bounced off against MF. I have to make it easy for most of you guys with your snail speed opamps and 3 terminal regulators.
So Robert, you can tell the difference with a single resistor change in the feedback loop? That sounds testable.
It is testable, and the feedback resistor would be the only plausible place that it could make a difference. A non-defective feedback resistor around an IC opamp is unlikely to have distortion at a level where it could be heard, but carbon comps do get defective. See, for example, this old article.
Well, he can demonstrate that if he wants, or it can just be asserted without any backup, and join the many audiophile tales of magick and wonder.😀
If it's a feedback resistor in a phono or mike preamp, there could possibly be an audible excess noise difference if the design is not robust, but that's a stretch. TBH, I don't use carbon film very much (metal film is very cheap these days), so perhaps there's a significant defect rate?
If it's a feedback resistor in a phono or mike preamp, there could possibly be an audible excess noise difference if the design is not robust, but that's a stretch. TBH, I don't use carbon film very much (metal film is very cheap these days), so perhaps there's a significant defect rate?
It's the first proposal I have seen in this thread that I could imagine a way of building something that could be tested in a sensible fashion!
There is a reason why the make-up gain/output stage of the LCRMKIII has a CC resistor for the feedback; and it 'aint 'cause it's easy because it's not. PITA because I hand match those.
I also use CC as stoppers and 4th pole in the RIAA
I also use CC as stoppers and 4th pole in the RIAA
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Go ahead and do the ABX on it. Then come back and say it doesn't matter in your snail opamp circuits that are swamped with reverse recovery spray from 4001 diodes.
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That was not my plan. two of your phono stages would cost $600. That's a level at which, across the forum there should be enough people willing to chip in a bit to meet that level. One is per your secret salsa and one has a standard metal film as we would all use. Fully characterise both on agreed test set then organise some blind testing according to an agreed protocol.
Would cost, would take time, but would (if done right) produce a real data point.
I'd certainly chip in to it.
Would cost, would take time, but would (if done right) produce a real data point.
I'd certainly chip in to it.
Why would you choose ABX rather than some other ears-only listening format?
I'd suggest opening a separate thread if you want to talk about passive components rather than IC op amps.
Let me think. Signal levels will be low, so normal nonlinear distortion of CC will be too low to be relevant. Thermal issues at LF will similarly be too small to notice. Is it grain contact effects in the CC, so it produces extra distortion for very small signals?morinix said:
Given CC drift, how long does the matching last? Using CC for feedback can only be because you like a little distortion with your music?
CC as stoppers are almost always unnecessary; a film resistor will do just as well, or even better sometimes. CC for a filter (even above the audio range) can only be because you want the frequency and phase response to vary somewhat with temperature, humidity and equipment age. I know: you want your customers to send the item back for 'servicing' every few years? A nice little earner!
Using CC for modern audio is like building a high performance car using a carburettor and old-fashioned ignition, running on leaded fuel.
Given the extremely reasonable prices asked for the products, I think putting all this in the context of greed is an undeserved slight.
If he uses CC for feedback resistors then the product price had better be reasonable! I'm sure the refurbishment price would be equally reasonable.
Curious about the mechanism here.
Is the error merely an error effecting the output stage?
Or, is this error one that modulates the rails, ending up modulating the highest voltage gain stages (and/or lowest signal level stage(s))?
If I get to pick the brand of resistors and the divider chain values pretty sure the distortion differences will reach the perceptable levels.
Same deal if I select parts and values to minimize distortion.
No magic just measurement based design.
Now previously having compared a discrete opamp to a single chip unit in a CD player the difference was not due to distortion but seemed to be about EMI rejection.
Same deal if I select parts and values to minimize distortion.
No magic just measurement based design.
Now previously having compared a discrete opamp to a single chip unit in a CD player the difference was not due to distortion but seemed to be about EMI rejection.
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