I know that this thread is about Chris's unit and not the broader discussion of distortions.
The distortion plot from Mbrennwa had the nasty looking spikes at third and fifth, which one would typically not get in and amp or dac of any decent design. Yet an amp of most any design, will have a healthy dose of second harmonic. So if you factor that in, well it's not all so bad.
And if one does a distortion profile comparison to any number of preamps units, one would find some interesting plots and provide some interesting discussion points. Though of course that would not change the plot of the LDR.
I'm sure you wouldn't agree with that, so we can just agree to disagree.
Nothing says you have to have any interest whatever in LDR volume controls for any reason at all. And most people don't.
Okay, I see that I need to explain a little. In a harmonic distortion profile at say 1khz at whatever power level you choose, the level of the second harmonic is going to be the highest of all the harmonics. It might be -70db or -80db or even less, so not exactly my "healthy dose", but still more than any of the other harmonic levels. This is what my own mosfet amps have tested at and I don't think they are atypical.
I don't have a printed chart to post, or even a Spice graph.
Does this help?
You can get another perspective on the distortion level by looking at the graph here, posted by George, courtesy of jackinnj, in Post #196
LDR Attenuator Impressions
You will see that both the second and third harmonics are down over 100db from the primary tone. You are not going to hear that. You are not going to hear that little spike of third harmonic in the graph on Post#288, though it is obviously there.
What you will likely hear, and this in only in a comparison to something very neutral like a stepped attenuator or precision potentiometer, is a small difference in tonal quality of the music.
How that sounds to you is up to you.
Yes, I think that’s exactly our (or at least my) point.
Look at all the 10k speaker cables and interconnects sold.
The Brooklyn Bridge has been sold many times as well.
So have any number of useless, harmful, unscrupulous, [insert problematic word here ] consumer objects.
Look at how many diesel Volkswagens are on the road. Watch some late night TV infomercials.
You should be thankful there are consumer agencies and people out there calling out faulty engineering across the board, because it saves countless lives yearly.
Also, those posting here in contradiction have sold orders of magnitude more devices in various fields. I’ll leave it to them to disclose should they choose.
You have yet to provide anything but listening impressions / subjective experience to describe the value and functional nature of a device which operates strictly within the confines of science and engineering.
I for one am glad there are engineers out there with the general public’s protection in mind.
A figure of speech of course. I’ve been known to do many things for good scotch, sans weaponry.
In more balanced terms I mean to say that those who take life too seriously make for unpleasant company.
I think the key here is a lack of admission that there is taste, that distortion can be pleasing. To not disclose this as a retailer is disingenuous.
I think psychologically average consumers aren’t prepared to accept that they’ve spent x sum in search of purity par excellence and really what they are enjoying deviates from the source.
Oh the terror!!!
Me? I’m ok with it. I’d rather own it than deceive myself.
The recordings I most cherish need some help anyhow, to be honest. On an imperfect medium, no less. I’m certainly not spinning Sheffield Labs or audiophile label discs in most cases.
But then again I don’t want a completely off the Wall result, I just want some sprinkles on my vanilla ice cream... not atomic gumball jalapeño pistachio crumble.
To me, the audio industry tracks rather well with the Swiss watch industry, even temporally, so it’s an excellent sociological parallel.
If you have a Rolex and enjoy it, that’s great. I’m ok with status symbols- not my bag but I accept that others are into it. BUT don’t tell me it’s ***more accurate*** than a Casio G-Shock. That’s where we have a problem.
But hey- do we really need atomic clock time keeping? Are you really going to be 500m underwater? Are you a Navy Seal?
I’m ok being off a minute here and there. So, why not wear a winder if you feel like it?
Swiss watches have survived only as luxury symbols, and have no real advantages in timekeeping.
So why not just own it and say it’s just for fun? Its also fun to take an imperfect medium and attempt to improve upon it.
This is why I have no inherent issue with LDRs.
The issue is firmly rooted in marketing claims and general behavior by unscrupulous vendors.
You say it’s better? Prove it. Period. Don’t tell me there’s some magic juju completely beyond the grasp of modern physics.
Does Ferrari have quantum engines wired with 99.999% silver wire and Furutech connectors? Is my Samsung washing machine benefitting from being filled with Audioquest hookup wire? Nope, just us lunatics over here in audio where our own listening abilities are somehow so uniquely mystical that engineering need not dwell here.
At least the Swiss just unabashedly say what it is your getting.
It’s rather sad to watch your hobby descend into a circus act...
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This is quite simple, review what customers have said via feedback about the level of service and product quality of the kit I provide. Here is some of that feedback: Excellent product & price, fast delivery. life is beautiful, Thank you Chris, you are a gentleman, I am happy Good service great product Fast and as described Amazing quality of product made by person of high integrity. Shipping was FAST!
and: Yes very impressed. Far superior to the Angel LDR and the Tortuga, and it bested my favourite passive which itself has bested many many active line stages. I think the best way to describe the sound is that is is very refined and accurate. Tonally very realistic, with a wonderfully silky top end. No shrill no distortion. Musical in a very natural unforced way. It just basically does not sound mechanical, it sounds like real music.
and: Yes very impressed. Far superior to the Angel LDR and the Tortuga, and it bested my favourite passive which itself has bested many many active line stages. I think the best way to describe the sound is that is is very refined and accurate. Tonally very realistic, with a wonderfully silky top end. No shrill no distortion. Musical in a very natural unforced way. It just basically does not sound mechanical, it sounds like real music.
I’m sorry but as I said before anecdotal evidence to me is insufficient. I’m glad you’ve finally taken steps to measure a preamp for distortion that you’ve been selling for a decade. It’s a step in the right direction.
This is not what we have been talking about.Chris Daly said:
If a nonlinear LDR can do this, just think how much better an ordinary linear resistor would be as a volume control! Unless, of course, people actually prefer a little low order distortion - which has been well known for many decades.
Anyway, it is not in dispute that people buy it and like it. The issue is the ridiculous claim that the nonlinearity of an LDR can be improved by 'improving' the drive for the LED light source, and the supporting claim that elevating the LED above 'ground' somehow improves things too. As I said, a really bad LED driver could degrade things - but not by adding harmonic distortion but light-music intermodulation.
As almost all LDR volume controls seem to use the same or similar optocouplers the only way one could sound genuinely different from the others is by degrading the signal more. PSU IM is one possibility, as I have said. Poor channel balance is another. I suppose a really bad one could have excessive stray capacitance and so a minor HF peak or rolloff, which might vary with attenuation.
Sorry for the rant.
This forum seems to have degenerated from a DIY (do it yourself) forum to a DIY (denigrate it yourself) forum.
This isn’t an amateur writer’s forum so let’s cut out all the embarrassing creative waffle and get down to the nitty gritty of trying to understand why LDR passive preamps can and do work effectively.
Where is the constructive discussion about why LDR preamps are so misunderstood?
I have spent thousands of hours listening critically to all versions of the StereoCoffee and other LDR preamps with a wide range of music and the SC has improved dramatically over the last few months.
The listening experience for those who haven’t heard one is that they provide an accurate, linear way of controlling volume without adding to or subtracting anything from the performance.
There is no sonic signature, complete silence at all levels and no audible distortion at any level.
Music seems to come from the source directly to the amplifier with nothing but air in between.
Not much technical data in that because it really is that simple.
Providing your amp and speakers are capable of uncoloured reproduction, from my experience you will hear every note, every harmonic, every breath just as the recording engineer intended.
My system comprises Aries Mini music server, FLAC files, CloneNote (latest redesign) and hybrid DIY 505 mini ESL panels and cost under $2000. So that would qualify as a budget system.
From my experience over 50 years of DIY, the whole concept is that you actually build and listen to your projects. You don’t judge the success of your projects by collecting data, you judge them by listening and enjoying. There is always something that doesn't sound quite right and your goal is to figure out how to correct it. I still expect to hear the niggling annoyances but with my current system there are none. Nothing but pristine beautiful music from wall to wall. Lucky me!
Take a look at the amount of second hand, expensive high end equipment on the market. The usual reason for selling is upgrading. Is the equipment performance not as good as the data predicted?
Was the real reason for buying? Product brand, astronomic price, reputation, impressive design, performance data or all of these?
Or is the real reason for selling because the buyer didn’t have a proper audition or was it a bad match for other equipment in the line?
Data alone cannot tell you how a piece of audio equipment will actually sound any more than data alone can tell you how a car will drive. Car reviews always include a test drive not just data.
So, what is this obsession with data by people haven’t heard the latest StereoCoffee?
This is a DIY Audio forum so why can’t we listen before we criticise or offer advice on something we don’t really understand? It strikes me as an indication of ignorance or a lack of DIY experience.
I wonder if LDRs' will be criticised when Chris gets his data report, whether good or bad?
Happy soldering,
Cheers, Rob
This forum seems to have degenerated from a DIY (do it yourself) forum to a DIY (denigrate it yourself) forum.
This isn’t an amateur writer’s forum so let’s cut out all the embarrassing creative waffle and get down to the nitty gritty of trying to understand why LDR passive preamps can and do work effectively.
Where is the constructive discussion about why LDR preamps are so misunderstood?
I have spent thousands of hours listening critically to all versions of the StereoCoffee and other LDR preamps with a wide range of music and the SC has improved dramatically over the last few months.
The listening experience for those who haven’t heard one is that they provide an accurate, linear way of controlling volume without adding to or subtracting anything from the performance.
There is no sonic signature, complete silence at all levels and no audible distortion at any level.
Music seems to come from the source directly to the amplifier with nothing but air in between.
Not much technical data in that because it really is that simple.
Providing your amp and speakers are capable of uncoloured reproduction, from my experience you will hear every note, every harmonic, every breath just as the recording engineer intended.
My system comprises Aries Mini music server, FLAC files, CloneNote (latest redesign) and hybrid DIY 505 mini ESL panels and cost under $2000. So that would qualify as a budget system.
From my experience over 50 years of DIY, the whole concept is that you actually build and listen to your projects. You don’t judge the success of your projects by collecting data, you judge them by listening and enjoying. There is always something that doesn't sound quite right and your goal is to figure out how to correct it. I still expect to hear the niggling annoyances but with my current system there are none. Nothing but pristine beautiful music from wall to wall. Lucky me!
Take a look at the amount of second hand, expensive high end equipment on the market. The usual reason for selling is upgrading. Is the equipment performance not as good as the data predicted?
Was the real reason for buying? Product brand, astronomic price, reputation, impressive design, performance data or all of these?
Or is the real reason for selling because the buyer didn’t have a proper audition or was it a bad match for other equipment in the line?
Data alone cannot tell you how a piece of audio equipment will actually sound any more than data alone can tell you how a car will drive. Car reviews always include a test drive not just data.
So, what is this obsession with data by people haven’t heard the latest StereoCoffee?
This is a DIY Audio forum so why can’t we listen before we criticise or offer advice on something we don’t really understand? It strikes me as an indication of ignorance or a lack of DIY experience.
I wonder if LDRs' will be criticised when Chris gets his data report, whether good or bad?
Happy soldering,
Cheers, Rob
Perhaps data may not tell the full story in some cases. Perhaps the main data points are incomplete. Perhaps the wrong thing is being measured.
However no carmaker makes claims to sell cars with a complete absence of data, while utilizing reasoning that defies basic electronic engineering, as is the case here.
The test drive portion of the review would never take place, as no credible company such as consumer reports would accept the evaluation sample.
More anecdotal evidence is not helping anyone’s case.
I enjoy listening too. I also enjoy driving.
I also know that I’m not impervious to fooling myself through any number of biases.
So I prefer to listen, drive and utilize other consumer objects that have been evaluated objectively for quality, safety and performance.
Then I’m able to make educated decisions and choose whatever fits the criteria I’m looking for.
Crowdsourced anecdotal information only takes one so far, as anyone who has browsed Amazons reviews can attest to.
Perhaps Chris’ preamp measures wonderfully, perhaps his erroneous logic simply lucked out in a way he hadn’t considered.
I don’t know the answers to these questions.
However I think it’s our duty to ensure people verify and objectively evaluate their products before making claims to the public.
However no carmaker makes claims to sell cars with a complete absence of data, while utilizing reasoning that defies basic electronic engineering, as is the case here.
The test drive portion of the review would never take place, as no credible company such as consumer reports would accept the evaluation sample.
More anecdotal evidence is not helping anyone’s case.
I enjoy listening too. I also enjoy driving.
I also know that I’m not impervious to fooling myself through any number of biases.
So I prefer to listen, drive and utilize other consumer objects that have been evaluated objectively for quality, safety and performance.
Then I’m able to make educated decisions and choose whatever fits the criteria I’m looking for.
Crowdsourced anecdotal information only takes one so far, as anyone who has browsed Amazons reviews can attest to.
Perhaps Chris’ preamp measures wonderfully, perhaps his erroneous logic simply lucked out in a way he hadn’t considered.
I don’t know the answers to these questions.
However I think it’s our duty to ensure people verify and objectively evaluate their products before making claims to the public.
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Since one can't isolate the undiscovered property of LDR's from all the rest there is really no point here.
Claiming a thermodynamic impossibility does not help the cause.
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*** Edit: also, take a peek at nezbleu’s link to the schematic. ***
I was speaking to his reference to anode / cathode of the LDR.
It’s my understanding there is no positive or negative terminal to an LDR.
So, if such a basic premise is confused one must wonder about the rest.
But yes re: LDR/Resistor refer to my initial post in the thread.
To me anything else is just hubris, the harbinger of downfall in any great tragedy.
Until then, I’ll stay with my ladder attenuator.
It even has a remote control *gasp*
If only I had some Bybees to glue to it.
(Regarding remotes: ones better half complaining that your state of the art stereo isn’t very state of the art if you have to get up every time you want to adjust the volume is also a form of distortion, and should be integrated into one’s complete calculation).
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Every word of that could be said of an ordinary volume control. Let's please keep in mind that this is a volume control, nothing more.
But it's not really that simple, is it? Otherwise you would have built every single circuit ever presented here. Before you decide to build something you look st the schematic, think about it, read what others have said, etc. We make decisions based on many factors, and we all react in different ways to the same evidence. Before I build anything I want to see a schematic that inspires confidence, and an explanation of the circuit that makes sense. I want to have confidence in the designer. I have not yet seen anything from Chris that I would bother to build. Sorry if that bothers you, I intend no disrespect to you or your decisions, but I have seen circuits that Chris has presented here that were laughable.
I really don't care why people buy or sell commercial gear, high- mid- or low-end. I build my audio gear, DIY right?
So I'm getting pretty tired of these posts telling the rest of us how to react to ridiculous claims from Chris and others about the magical properties of a volume control.
Please have a look at the schematic supplied by Chris Daley in this post https://www.diyaudio.com/forums/analog-line-level/273911-audio-ldrs.html#post4316034
If you can look at that and keep a straight face you are a better man than I. If you don't understand why I and others find that "circuit" frightening, just ask. And that is not the worst of many circuits Chris has posted here.
Now on top of questions of competence, Chris repeatedly makes the claim that he has a special understanding of LDR circuits, and that the drive for the LED, which does not pass any signal, is the major determinant of sound quality. He has never explained why he thinks that is true, and he has never supplied any supporting evidence, and he has never measured the product that he sells or compared it to a normal volume control.
Feh! I can't believe so many words have been wasted on this.
I can't believe how much anger is being generated on this supposed DIY Audio forum by people who have never even listened to the equipment they are criticising. Surely it doesn't fit into the spirit of DIY Audio forum and it's time people grew up.
Everyone wants to have the last say and I also can't believe how many words have been wasted ...on destructive criticism.
I'm out of here forever and going to enjoy some beautiful music on my LDR preamp.
Cheers,
Rob
Everyone wants to have the last say and I also can't believe how many words have been wasted ...on destructive criticism.
I'm out of here forever and going to enjoy some beautiful music on my LDR preamp.
Cheers,
Rob
Couldn't see that link nezbleu as it was so small 12kb, so I enlarged it, so here it is in all it's glory.
Cheers George
Attachments
There has been lots of discussion about why LDR volume controls are misunderstood by those buying them, and some of those selling them. The only reason you may find this discussion not 'constructive' is that it appears to conflict with your own opinion.robmid said:
You tried one. You liked it. The distortion is too small for you to hear. "Accurate, linear" may be confusing signal linearity with control law linearity, which is a confusion encouraged by some (but not all) LDR control sellers.
True for any sensible volume control method, including a simple pot.
That is your method of DIY. My method is to understand the technology, and only listen to stuff which I have reason to believe will be technically sound. I don't criticise your method, so why are you criticising my method?
We are offering advice on something we believe we understand better than others; in some cases perhaps better than the seller. Instead of providing counter-arguments to our technical criticisms they act like modern youngsters (whatever their age actually is) and just respond "you cannot say that". You cannot have your own private facts.
The technical claims made by him will remain untrue. You would need to directly compare the same photocouplers in a Chris circuit and (say) a George circuit to see whether they perform better in one than the other. Even then the harmonic distortion would not be the issue; IM is the issue, as harmonics cannot be affected by the light source.
Yes, that circuit has some of the hallmarks of a Chris design:nezbleu said:
- random placement of diodes and transistors
- peculiar placement of other components
- components whose function can only be described as cosmetic
I note that in 2015 he was using a 7805 voltage regulator driving the LEDs via variable resistors - remarkably similar to George's circuit, except for the 'Chris' extra touches mentioned above.
Me too. The supporters should put up someone who actually understands electronics to give a reasoned technical rebuttal of our criticisms, or keep quiet about us and merely repeat their mantra 'I bought it, I like it'.
All the anger seems to be coming from Chris's supporters, so yes I agree it is time they grew up. It is not in the spirit of DIY Audio for someone to sell a commercial product, promote it here in the main forum area, make false claims about it here, yet not provide a circuit diagram so others can properly assess it. We could even find that the alleged 'current source/sink' arrangements are nothing of the sort; anything is possible with a Chris circuit.robmid said:
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