I understand ... psychological
so you say that in a preamp a change of the feedback resistor is practically inaudible ?
I thought that Holco were more linear and less noisier than an unbranded one
actually I was thinking of doing the same in another old preamp
It depends. First, on what resistor you're comparing it to and second, on the degree of difference. If we look at noise and Johnson noise is dominant, small changes in excess noise are... well, lost in the noise. If we look at linearity and (for the voltage levels we're talking about) it's the difference between -140dB distortion and -150dB distortion, again this effect is absolutely swamped by everything else as well as being well below any demonstrated auditory threshold.
Thank you ! I am convinced now
I mean ... it is important to fix some points
Honestly I was skeptical for resistors .... but not for capacitors. On this I am completely convinced that there are some better than others
But resistors are also important
Let's say that one "exotic" resistor per feedback is not a big cost anyway
But i was worried also for all the others and without reason.
Thanks again
Kindest regards,
gino
I mean ... it is important to fix some points
Honestly I was skeptical for resistors .... but not for capacitors. On this I am completely convinced that there are some better than others
But resistors are also important
Let's say that one "exotic" resistor per feedback is not a big cost anyway
But i was worried also for all the others and without reason.
Thanks again
Kindest regards,
gino
Hi gino,
No, I don't think you're hearing things. Okay, maybe good things
Upgrading critical resistors may actually improve the sound, as opposed to just "sounding different".
The TX2575's were recommended by a good friend and guru of mine, as detailed in this thread.
There will always be skeptics who doubt digital cables, premium resistors and what not. Believe in your ears, not what people (including me) write on the interwebz
No, I don't think you're hearing things. Okay, maybe good things
Upgrading critical resistors may actually improve the sound, as opposed to just "sounding different".
The TX2575's were recommended by a good friend and guru of mine, as detailed in this thread.
There will always be skeptics who doubt digital cables, premium resistors and what not. Believe in your ears, not what people (including me) write on the interwebz
¨Hi gino,
No, I don't think you're hearing things. Okay, maybe good things
Upgrading critical resistors may actually improve the sound, as opposed to just "sounding different".
The TX2575's were recommended by a good friend and guru of mine, as detailed in this thread.
There will always be skeptics who doubt digital cables, premium resistors and what not. Believe in your ears, not what people (including me) write on the interwebz
Good morning and thank you for the valuable reply
let's say that 2 higher grade resistors do not break the bank
and your experience actually confirms even if the situation is different.
We were "palying" with a prototype line preamp
In general I guess parts in series with the signal are critical
and maybe where the signal is "weak" they are more critical ?
Maybe also good industrial parts exist, without having to seek for exotic ones.
Thanks again
Regards,
gino
It's not that simple. Parallel with the signal matters too. You can ignore much of what you read about 'signal path'. Where the signal is weak distortion may be less of an issue but noise may be more of an issue.ginettot61 said:
Given normal decent commercial quality, it is very unlikely that different resistors will sound different in a preamp. An exception is carbon composition, which can introduce noticeable amounts of distortion and noise. Some people may prefer this. Faulty resistors can slip through too, even from reputable makers.
did you compare by putting back the original resistor?
It may be that simply removing and soldering back in the resistor of any good and appropriate type is what created the audible difference.
BTW, I try to run all resistors at less than 50% of power rating and preferably <25%.
But when it comes to critical resistor, for example the upper leg of the NFB, I ensure that resistor never dissipates more than 10% of power rating for worst case peak current condition.
The 29Vrms signal level is ~63% average for a 250mW resistor.
BUT the PEAK dissipation at 29Vrms is 134% of the Pmax for a 250mW carbon film resistor.
Two 1k6 and one 1k8, 600mW metal film, connected in series for that 5k NFB would dissipate ~10% average of the resistor power rating.
It may be that simply removing and soldering back in the resistor of any good and appropriate type is what created the audible difference.
BTW, I try to run all resistors at less than 50% of power rating and preferably <25%.
But when it comes to critical resistor, for example the upper leg of the NFB, I ensure that resistor never dissipates more than 10% of power rating for worst case peak current condition.
If I am understanding Jacco correctly, he is implying the same thing. Make sure the resistor temperature does not change significantly due to changes in signal level.
the 9Vrms signal level is only 6.5% average for a 250mW resistor.
The 29Vrms signal level is ~63% average for a 250mW resistor.
BUT the PEAK dissipation at 29Vrms is 134% of the Pmax for a 250mW carbon film resistor.
Two 1k6 and one 1k8, 600mW metal film, connected in series for that 5k NFB would dissipate ~10% average of the resistor power rating.
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Good morning. Actually no
My friend was not convinced with the overall sound and the project stopped
But I tend to trust him on evaluation by ear
I felt something like a more spacious, cleaner ...
ehm ... actually everything was mounted on a perf board ... one for circuit test
maybe was just a case of cleaner contacts ???
i see that the noise depends on temperature and I think the higher the current the higher the temperature
But it was only for the feedback ... with very little current involved
One resistor per channel do not increase cost so much in the end
Apart from this one thing is very strange to me
How difficult is to find a very good sounding line preamp
and how much the sound of the line preamp impacts the overall sound
I read an awful lot of reviews where even cheap power amps performed really well when mated to a good line preamp
A bad line preamp can kill the sound literally
This is a big mystery to me
Thanks and regards,
gino
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If only!ginettot61 said:
Yes, but even there the differences are smaller than many people claim and only relevant to certain caps in a circuit. As SY said (for resistors, but the same applies to caps): use engineering to choose an appropriate good quality commercial component. Then you can be reasonably sure that any change apparently heard when substituting an 'audiophile' version is either imagination or deterioration.
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