youknowyou, yeah that fits my case b).
I've also already commented on Ryelands posts.
Having done many blind tests with FX and distortion devices I can say that distortion in audio reproduction generally degrades sound quality subjectively and objectively. Your subjective preferences may be different but objectively you cannot change the signal degradation.
Before you throw stones at me, many people and their systems are quite forgiving to distortion and they can't hear it in blind tests, but as soon as the comparison is sighted they start to make ridiculous claims again... it's fun to watch and listen to the excuses why differences disappear when all you do is hide where a cable is connected to.
So are you saying that LDR attenuators produce audible amounts of distortion or not? You can't have it both ways.
If you are arguing for very low but still audible distortion then how do you account for the contradicting claims of pronounced bass (which would mean lots of low frequency distortion) or change in dynamics?
=> People hear what they want to hear.
---
I am asking for conditions because Pass' measurements show over 0.1% with 2V into a NSL32SR3 at 277 ohms.
If you just measure it at a Mohm then I guess it's like measuring an amplifier unloaded ...
I've also already commented on Ryelands posts.
Having done many blind tests with FX and distortion devices I can say that distortion in audio reproduction generally degrades sound quality subjectively and objectively. Your subjective preferences may be different but objectively you cannot change the signal degradation.
Before you throw stones at me, many people and their systems are quite forgiving to distortion and they can't hear it in blind tests, but as soon as the comparison is sighted they start to make ridiculous claims again... it's fun to watch and listen to the excuses why differences disappear when all you do is hide where a cable is connected to.
So are you saying that LDR attenuators produce audible amounts of distortion or not? You can't have it both ways.
If you are arguing for very low but still audible distortion then how do you account for the contradicting claims of pronounced bass (which would mean lots of low frequency distortion) or change in dynamics?
=> People hear what they want to hear.
---
I am asking for conditions because Pass' measurements show over 0.1% with 2V into a NSL32SR3 at 277 ohms.
If you just measure it at a Mohm then I guess it's like measuring an amplifier unloaded ...
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2V (0.1%) is the output voltage for a 6.33V input at -10dB attenuation.
If you mean 2V input voltage then with -10dB attenuation it will be 0.63V output voltage. This approximates to 0.018% of distortion...that's about -75dB! Will that be audible to you?
If you are arguing for very low but still audible distortion then how do you account for the contradicting claims of pronounced bass (which would mean lots of low frequency distortion) or change in dynamics?
the user who said that have done a comparison between his previous line stage and the ldr attenuator. The increase in bass and increase in dynamics does not mean that the ldr increase bass or increase dynamics due to the distortion, it mean that his previous line stage wasnt as transparent which hindered bass and dynamics.
I will try a lightspeed and compare to pass b1.
the user who said that have done a comparison between his previous line stage and the ldr attenuator. The increase in bass and increase in dynamics does not mean that the ldr increase bass or increase dynamics due to the distortion, it mean that his previous line stage wasnt as transparent which hindered bass and dynamics.
I will try a lightspeed and compare to pass b1.
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I'm "the user" and the reported comparison was between a passive stepped attenuator and the LDR attenuator. I was surprised at the results as I didn't expect them.
Well, I cannot hear -100db.
If you can hear -100db., then congratulations and all the best.
I have been reading this thread all morning with great interest. Unfortunately a little less bile and a little more respect in contributions would make it a much better read IMO.
I use a Lighter Note LDR Attenuator I built from a kit supplied by Uriah Dailey (who seems to have gone AWOL of recent times). It was relatively cheap and a fun build which I think sounds fabulous. (The Lighter Note is a variant of George's Light Speed and purchased solely because I wanted more inputs and it was cheaper in DIY form). It was compared to and ultimately replaced a Sutherland Director Linestage despite the latter's superior distortion specs. Concerned that an attenuator with so many "faults" should sound so good I purchased a Supratek Chenin Preamp which seemed to have an almost cult like following in some quarters and perhaps a worthy replacement for the lowly Lighter Note. After a considerable amount of time comparing the two units (including tube rolling to an obsessive level) the Lighter Note remains my preference.
A friend who was using a Nelson Pass B1 buffer tried the Lighter Note and promptly ordered and built one. It is now his reference. Other friends came over to hear the lighter Note and brought their respective preamps to show up the DIY LDR ursurper for all it's faults. Of note were a Coincident Statement Linestage, PrimaLuma Dialogue 3 and Parasound Halo JC2. In all cases the owners acknowledged with substantial surprise how good the Lighter Note sounded. One subsequently sold his preamp and is now an LDR convert and the others still feel a bit let down that their comparatively expensive preamps could not wipe the floor with the Lighter Note.
The point is that all the preamps I have heard the Lighter Note compared to have much better distortion specs and are more widely acknowledged as high quality and great sounding preamps in their own right. Those that have heard the comparisons have very good systems and good ears and openly acknowledge the stunning transparency and naturalness of the LDR "sound". So for those that wish to argue the finer points of comparative resistor distortion and degradation of the signal I thank you for providing such learned insight into the science and skill involved in preamplifier design and performance measurement. Alas I am not capable of offering knowledgeable input in that area. I do however urge you to give one a listen and share what you think and perhaps ponder as I do - why does it sound so good when it's supposed to (technically) sound so bad?
PS* I have been following the Tortuga LDR as an upgrade to my Lighter Note. The ability to autocalibrate the LDR's, adjust input impedance and a remote volume control make it very compelling. Plus I can get it as a DIY kit!!
Happy New Year Everyone. 🙂
I use a Lighter Note LDR Attenuator I built from a kit supplied by Uriah Dailey (who seems to have gone AWOL of recent times). It was relatively cheap and a fun build which I think sounds fabulous. (The Lighter Note is a variant of George's Light Speed and purchased solely because I wanted more inputs and it was cheaper in DIY form). It was compared to and ultimately replaced a Sutherland Director Linestage despite the latter's superior distortion specs. Concerned that an attenuator with so many "faults" should sound so good I purchased a Supratek Chenin Preamp which seemed to have an almost cult like following in some quarters and perhaps a worthy replacement for the lowly Lighter Note. After a considerable amount of time comparing the two units (including tube rolling to an obsessive level) the Lighter Note remains my preference.
A friend who was using a Nelson Pass B1 buffer tried the Lighter Note and promptly ordered and built one. It is now his reference. Other friends came over to hear the lighter Note and brought their respective preamps to show up the DIY LDR ursurper for all it's faults. Of note were a Coincident Statement Linestage, PrimaLuma Dialogue 3 and Parasound Halo JC2. In all cases the owners acknowledged with substantial surprise how good the Lighter Note sounded. One subsequently sold his preamp and is now an LDR convert and the others still feel a bit let down that their comparatively expensive preamps could not wipe the floor with the Lighter Note.
The point is that all the preamps I have heard the Lighter Note compared to have much better distortion specs and are more widely acknowledged as high quality and great sounding preamps in their own right. Those that have heard the comparisons have very good systems and good ears and openly acknowledge the stunning transparency and naturalness of the LDR "sound". So for those that wish to argue the finer points of comparative resistor distortion and degradation of the signal I thank you for providing such learned insight into the science and skill involved in preamplifier design and performance measurement. Alas I am not capable of offering knowledgeable input in that area. I do however urge you to give one a listen and share what you think and perhaps ponder as I do - why does it sound so good when it's supposed to (technically) sound so bad?
PS* I have been following the Tortuga LDR as an upgrade to my Lighter Note. The ability to autocalibrate the LDR's, adjust input impedance and a remote volume control make it very compelling. Plus I can get it as a DIY kit!!
Happy New Year Everyone. 🙂
Ah finally the Lighter Note has made an entrance into this thread. This is the one where I had thought I would make an entry into the LDR world, but it didn't happen for me. Nice to read your experiences.
As for Tortuga, there is to be the next generation controller appearing later this year, and you might wish to wait for that.
Congratulations to Bilbo,
for a review that does not exaggerate, nor make false claims that cannot be substantiated.
Bilbo and his friends all like the sound and state their preference.
They do not claim the impossible.
Thanks.
Stvn,
go back and read your post1. Compare your claims to Bilbo's.
for a review that does not exaggerate, nor make false claims that cannot be substantiated.
Bilbo and his friends all like the sound and state their preference.
They do not claim the impossible.
Thanks.
Stvn,
go back and read your post1. Compare your claims to Bilbo's.
Thanks - interesting.
I built a Lighter Note (LN) in 2010 and used it for about four years before replacing it with a pair of Intact Audio "autoformer" VCs. These sound better in my system. The differences between the LN and George's Lightspeed are, of course, that the former uses a constant current PS and that its parameters (max, min shunt and series resistance, etc) can readily be adjusted while the latter uses a voltage regulator. The LN sounds better than the DIY'd Lightspeed I tried but I must stress that I've not heard George's production unit and that it differs in significant respects from my prototype.
My guess is that the AVCs sounded better because, as Scott Wurcer hinted above, my system has highish source Zouts and lowish amp Zins and that, as we all know, no passive attenuator is at its best in these conditions. Even so, the LN worked very well and sounded way better than both an Alps pot (mine wore out after ~20 years) and the stepped attenuator I replaced the pot with. (Gallingly, the SA cost more than the LN.)
In light of this thread, yesterday I put the LN back into my system in place of the AVCs and listened for several hours. I've reverted to the transformers as the LDRs do lack "presence" in my elderly setup but also because, though the clarity is still striking, there's a slight HF edge that I'd forgotten about. As you know, the LN by-passes the series LDRs with high-value resistors to "improve" HF performance with, I assume, a touch of parasitic capacitance. I'm minded to remove them and listen again.
At the risk of repeating myself, two conclusions follow from yours and the many similar observations. On the one hand, some conclude that those who make such reports are either deluded or, despite proffering no pertinent evidence, that they like a touch of distortion. The implicit assumptions seem to be (reasonably) that an LDR's distortion is third harmonic and (much less reasonably) that the distortion of other attenuation devices can safely be ignored. I have to say I find professional engineers arguing repeatedly that datasheets trump trials very strange, especially as the three separate citations in this thread of that Silonex app note provoked no response.
Others (me, even) argue that THD is not a meaningful measure of performance and that, as with the example I gave of Nelson Pass and Cyril Bateman on NFB circuits, the devil is not only in the detail but that he resides in the time domain. (Music's like that.) I don't think it reasonable to expect boutique manufacturers to have the facilities, the time or even perhaps the skills - I certainly don't - to perform the relevant tests, esp given that the people who most demand them are most likely to dismiss them unread and least likely to become customers.
Finally, let's bury the myth that LDRs are complex circuits. True, auto-matching, auto-calibration and CC power supplies can be elaborate but they are ancilliary circuits not in the so-called audio "path". Every LDR device I've seen uses one shunt and one series LDR per channel, nothing else, especially no in-circuit mechanical switching or contacts.
OK, so they ARE complex circuits. Especially compared to a single potentiometer.
From all the wisdom of this thread, they are non-distorting distorting non-linear attenuator effects boxes that cause audible inaudible distortion with simple complex circuits.
Jeez, can't you people commit to just one story even if it is made up? 😀
Jeez, can't you people commit to just one story even if it is made up? 😀
The way I see it, if we consider a perfectly linear preamp has a transfer function K, a LDR preamp with transfer function K’(s) which is not perfectly linear, and everything else (power amp, speaker, room … and the brain) has a response of H(s). Then with LDR, the overall system response is K’(s)H(s), while response with a perfectly linear pre-amp will be KH(s). Unless H(s) is perfectly linear, which it is not, it’s entirely possible that K’(s)H(s) gives a more linear overall system response, as K’(s) serves as a filter to compensate the non-linearity of H(s).
I would argue that for LDR to have the benefit many have perceived, the effect of the filter should be significant enough – so the “distortion” it introduce should be audible. Some might call it an “effects box”, I call it a filter to enable better overall system linearity.
Others might say that such filter is the job of a tone control, but not everyone has a tone control and it would be quite a challenge to emulate the response of a LDR by a tone control.
The job of a tone control is not to add distortion, but to modify frequency response. A tone control is a filter. A distortion box is not usually called a filter. so you may cause confusion by calling it such yourself.cwtim01 said:
I would expect the frequency response of an LDR to be fairly flat, so it should be trivial to emulate it with "a tone control". I think it is unlikely that whatever an LDR does is done via a filter effect. I also think that it is unlikely that its action is to correct for distortion elsewhere; effective pre-distortion is hard enough to do deliberately, so unlikely to be done by accident!
Hi DF96,
My naming convention maybe bad (certainly I'm not a competent engineer), but I think you would agree that the possibility that K'(s)H(s) is more linearly than KH(s) definitely exist - correct?
On the contrary, I do think people come by these nice audio stuffs by accident, with years and years of trial and error by the thousands of audio lovers, they happen to come across a few things that they found to have a positive effect.
My naming convention maybe bad (certainly I'm not a competent engineer), but I think you would agree that the possibility that K'(s)H(s) is more linearly than KH(s) definitely exist - correct?
On the contrary, I do think people come by these nice audio stuffs by accident, with years and years of trial and error by the thousands of audio lovers, they happen to come across a few things that they found to have a positive effect.
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Could you elaborate?
Mathematically, I offered a possible explanation. In the real world, people reported their experience.
Mathematically, it's possible that every air molecule in this room will suddenly move over to one side, suffocating all of us.
I have not prepared scuba tanks for that eventuality.
I have not prepared scuba tanks for that eventuality.
Besides talking about non-linear systems which don't just cancel?
Well, start with the fact that LDRs are nonlinear in impedance, so two channels even if matched will have a different signal distortion profile and magnitude.
This signal distortion also changes with volume control position, both in profile and magnitude.
Third is the signal dependency, which also results in changes in distortion.
To say that any of that would even remotely cancel at any volume control position with real music in users' wildly different systems is just absurd. It's like expecting two noise sources reducing total noise instead of adding up.
edit: As for linear effects, just use an EQ. That's what EQs are for. Generally speaking, trying to fix deficiencies in some devices/systems by adding another deficient device is not a good idea.
Well, start with the fact that LDRs are nonlinear in impedance, so two channels even if matched will have a different signal distortion profile and magnitude.
This signal distortion also changes with volume control position, both in profile and magnitude.
Third is the signal dependency, which also results in changes in distortion.
To say that any of that would even remotely cancel at any volume control position with real music in users' wildly different systems is just absurd. It's like expecting two noise sources reducing total noise instead of adding up.
edit: As for linear effects, just use an EQ. That's what EQs are for. Generally speaking, trying to fix deficiencies in some devices/systems by adding another deficient device is not a good idea.
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