OP here Happy New Year.
I got corrected only in the sense that I learned that there was a small amount of low order distortion from the LDR's. I couldn't hear it and didn't know it was there. There is no mention of added richness and warmth in my comments on the sound.
I have never professed that the Lightspeed Attenuator system has ultimate low distortion figures, but what's there is, is small and dwarfed by other system distortions, and what small amount is there, is like the 2nd harmonic distortions of tube gear, which is pleasing to the ear.
For those that want to draw conclusions without listening, and are only interested in the figures.
Here are some measurements they can obsess over for the >$25K DarTZeel NHB-18NS preamp which also uses the Lightspeed Attenuator system, but unfortunately these include their active output buffer within these measurements as well, which even be better if taken out of the equation.
http://cdn.stereophile.com/images/archivesart/607D18fig7.jpg
http://cdn.stereophile.com/images/archivesart/607D18fig8.jpg
Just to add, here is the reviewers final words, if one can believe them??
"Conclusion
Inserting the NHB-18NS into my already excellent-sounding system was like being in the middle of an otherwise grand tropical vacation and suddenly having all the bugs disappear. However, whether any part of the darTZeel's singular performance strikes you as oh-so-right or just too much will in part be determined by the associated gear"
Cheers George
For those that want to draw conclusions without listening, and are only interested in the figures.
Here are some measurements they can obsess over for the >$25K DarTZeel NHB-18NS preamp which also uses the Lightspeed Attenuator system, but unfortunately these include their active output buffer within these measurements as well, which even be better if taken out of the equation.
http://cdn.stereophile.com/images/archivesart/607D18fig7.jpg
http://cdn.stereophile.com/images/archivesart/607D18fig8.jpg
Just to add, here is the reviewers final words, if one can believe them??
"Conclusion
Inserting the NHB-18NS into my already excellent-sounding system was like being in the middle of an otherwise grand tropical vacation and suddenly having all the bugs disappear. However, whether any part of the darTZeel's singular performance strikes you as oh-so-right or just too much will in part be determined by the associated gear"
Cheers George
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Just to add to the above Miller Audio Test distortion graphs of the NHB-18NS preamp going through it's Lightspeed Attenuator type volume control.
Here are the ones for the New >$32K Dan D'Agostino Momentum Preamp For the distortion obsessed they can compare.
http://cdn.stereophile.com/images/814Dagofig7.jpg
http://cdn.stereophile.com/images/814Dagofig8.jpg
Cheers George
Here are the ones for the New >$32K Dan D'Agostino Momentum Preamp For the distortion obsessed they can compare.
http://cdn.stereophile.com/images/814Dagofig7.jpg
http://cdn.stereophile.com/images/814Dagofig8.jpg
Cheers George
You can't directly compare measurements directly from 2 completely different test rigs. The fact that the NHB-18 has higher distortion does not allow any conclusion.
Your words seem to suggest that DarTZeel are using your designs. Would you care to clarify what you mean as it could be horribly misconstrued.
Your words seem to suggest that DarTZeel are using your designs. Would you care to clarify what you mean as it could be horribly misconstrued.
You guys just don't give up!
Here is one of the questions presented to Hervé Delétraz designer and owner of DartZeel in a 6 Moons interview! And he calls it a "Pleasure Control" which you could do with.
Q: What is wrong with conventional volume controls?
A: You lose something. I use a system that varies resistance with light. However, until all the patents are in place, I would prefer not to specify the details.
BTW: He can't patent it as it's already been done, by you know who, back as far as the early 70's
Cheers George
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Erm you are the one who said "the >$25K DarTZeel NHB-18NS preamp which also uses the Lightspeed Attenuator system". As lightspeed is YOUR product you are inferring that they use YOUR design so YOUR product is as good as theirs. I asked you to clarify if there is actually any input from you in that product based on the possible misinterpretation of what you have said.
It might be my product, but I never patented it back in the 70's (I should have) and therefore nobody can patent it now because it's not new, that's why there are many clones.
Nothing more needs to be said to you Bill, you obviously have made your mind up on things, without even listening to one.
Cheers George
Nothing more needs to be said to you Bill, you obviously have made your mind up on things, without even listening to one.
Cheers George
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Your claims/conclusions cannot be justified.
They are a figment of your imagination.
Mindful that the OP simply reported what he heard when using the DUT, what do you mean here by "justified"? Are you, despite not having heard it, suggesting that there could not be a perceptible difference between it and his "reference" SA? If so, it strikes me that it's your claims that are imaginative, not the OP's. If not, apologies for being dumb but can you clarify?
I make the point because, though I now use an autoformer VC, I briefly used a Lightspeed circuit and, for several years, a Lighter Note one. Despite the only difference between them being the LED power supply, they sound slightly different to each other and very different to the budget SA they replaced. I can't say why and am not entirely convinced by George's suggestions (I've nothing better to offer) but the difference was so readily perceptible (yes, I paid attention to impedance matching and occasionally reverted to the SA) that I'm inclined to believe that those who insist a priori that the perceived differences are but a figment of an over-eager listener's imagination are more obdurate than sceptical.
Ah. See above.
I agree that there can be a difference in sound.
But claims that the performance is improved
eg the channel balance was improved
music images became tighter
and more focused
bass response was more pronouned and deeper
Dynamics were much more
and the list goes on and on
Then he finishes with
But claims that the performance is improved
eg the channel balance was improved
music images became tighter
and more focused
bass response was more pronouned and deeper
Dynamics were much more
and the list goes on and on
Then he finishes with
What proportion of testers/listeners came up with that conclusion? Or was that another imaginative invention that STV came up with?
No, You would know if I was trolling. Just trying to clear up some confusions in the way things were written.
Thank you for clearing that up.
A respected colleague of mine, not AFAIK a visitor to this forum but with impeccable engineering credentials in instrumentation and audio, argues that, in a milieu in which amateurs are active, a useful maxim is to "accept the report but reject the explanation". I read the OP's report in that spirit, not one of sneering at his enthusiasm or questioning his integrity.
In any case, though I accept that the language is on the flowery side, his report generally accords with my experience of LDR circuits. I can't say more as I've not heard the Tortuga Audio unit and, at the price, won't get to.
I've followed your posts for long enough to hope you'll agree that the relationship between electrical and perceptual parameters is a deal more complex than a simple reading of datasheets might suggest. Almost immeasurable differences in electrical performance can strongly impact on how audio is perceived - and, of course, vice versa.
Your point may be formally correct but it's a bit cheap for all that. Were I so minded (I'm not), I'd soon find dozens of comments on pertinent threads here and elsewhere that could reasonably be classified under "why LDRs are no good as VCs", many from professionals in engineering but rank amateurs in psychology.
(Were someone to offer me £1 for every one that bangs on - without a shred of evidence BTW - about people preferring a touch of this or that colouration and demands data without their authors producing any of their own or showing much by way of knowledge of the literaure, I might just get to buy that Tortoise thingie.)
With completely immeasurable, nonexistent differences there can still be big differences in perception - it's called cognitive bias, placebo effect, new toy syndrome, prejudices ...
So I don't see how the above statement is true. The main problem is the confusion of correlation with causation. It's like putting a magical fuel saving device in your car and then subconsciously driving more economical. How can you then conclude that the magical device is what saved the fuel? But that's exactly what people do all the time.
Repeat this experiment blind and it will fail, most of the time, as it should! But then these people will blame the blind test... sigh.
People hear what they want to hear.
I'm sure that if LDR attenuators were the de facto standard then we'd instead see people arguing for a tighter and more focused image and more pronounced and deeper bass response etc. for example with metal film resistors here.
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