That's it. Distance between pot sections and pot construction as well. And a potentiometer value - the higher resistance the worse. You can easily measure this.
I use no higher pot value than 10k, for above reasons. Also, high value pot almost always results in huge dependence of frequency response on pot angle volume setting.
One important factor that we learned, by experience, 35 years ago, was that many QUALITY pots, at the time, had 'bad spots' that were position sensitive on the pot. Hit a bad spot and you had diode like distortion. While it may not be as apparent today, this showed that some pots don't like current flowing in the wiper. This limits the actual range of uses for the pot, because you can't load the wiper, and not get distortion in some settings.
Hi at all members, i have read almost 300 pages briefly before!!! very interesting arguments, but it's also necessary for my proper alignment in this discussion.
In my experience carbon resistors sound much better (more informations) than other resistors or pots, also a bit more noisy, but informations are more important over the noisy and a one perfect linearity , i think.
For the last two necessity is better a switched attenuator with carbon composite resistors.
Francesco.
Last edited:
I do not works with tubes, and for SS 10k load is no problem. To me, 50k and more is unacceptable.
Carbon resistors are much less linear than even carbon film resistors. They also have a much higher tempco. The "better sound" may be an artifact of the non-linearity.
Carbon comp pots should be avoided (I don't think they are made today, largely supplanted by conductive plastic). thoes had real problems with wear. The conductive plastic pots vary a lot as well. Somve vendors, like Alps and Nobel are quite good, almost as low distortion as discrete resistors. Others are 10-20 dB higher (the generic Asian brands for instance). Its very difficult to get extended frequency response with high value pots, you need very low input cap devices on the output. Never let DC through the wiper of a pot, every bit of contact resistance will show as noise, and it only gets worse over time. Cermet pots are also less satisfactory. They also have contact resistance variation problems.
Carbon comp pots should be avoided (I don't think they are made today, largely supplanted by conductive plastic). thoes had real problems with wear. The conductive plastic pots vary a lot as well. Somve vendors, like Alps and Nobel are quite good, almost as low distortion as discrete resistors. Others are 10-20 dB higher (the generic Asian brands for instance). Its very difficult to get extended frequency response with high value pots, you need very low input cap devices on the output. Never let DC through the wiper of a pot, every bit of contact resistance will show as noise, and it only gets worse over time. Cermet pots are also less satisfactory. They also have contact resistance variation problems.
I already have told that carbon comp resistors are not more linear (as Vout Vs. Shift,) but are linear about Vout Vs. Freq).
I agree that they have other big problems as tempco,durability, precision, etc. but the main question is that they sounds better than others, and here we must judge its for their sound quality prior other aspect.
We not want to build an industrial machinery here, but a sound machine.
Francesco.
Last edited:
Is there no room here for sound appreciation which is not supported by measurements, or other known technical data?
Hugo, IMHO it's not the subjectivism per se that is the problem. I think the real problem is when someone is trying to push their own subjective assessment down other people's throats. Realistically, unless we start expressing ourselves only in math formulas, most of what we say is just a personal opinion.
It would benefit the forum if we just respected that someone else may have their own liking when it comes to sound, possibly with no scientific basis.
That being said, I also don't like it when, with great authority, "universal truths" are being spewed at everybody.
It is not my intention to open a can of worms nor to impose a policy. You guys perfectly understand what I meant to say. Therefore, lets not derail this thread with a objective vs. subjective discussion but continue the nice and respectful conversation about attenuators as it has evolved until now.
In brief: Topic, please.
In brief: Topic, please.
I have made experiences in solid state and tube circuit without feedback.
Together my friends we have heard differences between resistors and, at the end, all we have appreciate the carbon type for their:
- major infos
- microdetail
- air.
Not only my friends prefer carbon comp over metallic resistors (ask some tubes guys).
Francesco.
That's a very interesting observation and info – at least, it interests me very much.
Can any one suggest why is it so from the technical aspect?
- Status
- Not open for further replies.