LSA Voyager GAN Amplifier
@mivmike are you just upset they kicked you out? I read that thread, it looks like this is the 3rd of 4th time. It seems you get no love from the people there. The sychophants, will often do further analysis on the data posted, compare to others, etc. If your attention span is one graph, you should not get angry at others, but look to yourself. |
This may not be the most out there thing I have heard in 30+ years in audio, but it ranks right up there, and certainly the top of the last year. It is probably just better to admit you are not an expert on what measurements can be made and what they can tell us. I will let Bruno know next time I see him that you want to teach him how to design amp properly. I am sure he will welcome the input.
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The "noise" from these resistors wouldn't even begin to register let alone reduce your THD+N to -92db at any reasonable amp power. You didn't state what power level you were using, so claims of distortion impact are suspect. No need for exotic and very expensive Mundorf resistors though. There are two parameters, one is thermal modulation, and that is a factor mainly of size, and the other one is voltage dependent resistance, and that just requires the right resistor material, it does not need to be at all exotic. Of course the speaker driver THD is -50 to -60db. |
Judging by this statement, and the name, I will make the wild guess that you are also "amplifierdude", so did you already get banned with that name here? How many times did you get kicked off of other websites? I don't believe YOU made that test with the resistor. Those numbers were taken from ASR I suspect, but not with Mills resistors. From what I can tell of your other posts, you don't know how to use your Dscope. |
@mivmike ,
The one you indicated as balanced has worse channel matching. The one you indicated as unbalanced, had unrealistic channel matching. 0.005% gain difference. That is highly unlikely on anything "real" two channel. The other measurement was matched to 0.015db between channels. I think you need to spend more time with your tools before posting stuff and learn to interpret what your post means. |
I think you don't understand what the measurements mean and I expect you are using the equipment improperly. Channel matching to 0.005% as your first picture shows is unnatural and highly unlikely. It is difficult to get that from lab grade reference DC sources, let alone a consumer audio device. The second unit at 0.015db difference is still exceptionally good channel matching. The amplitude accuracy of your equipment is 0.7% (0.06db). The changes you are showing are likely well within the short term thermal drift of the equipment, simply from output/input impedance. Balanced is not going to fix the issue. It is even harder to match/maintain perfect gain between channels with balanced taking into account a proper AES balanced connection has match source/load impedance and the absolute output will be a function of those resistors and never accurate to 0.005%, and I would be quite happy if within 0.015db, but even that is highly unlikely. |
🤦♂️🤦♂️🤦♀️ |
🤦♂️🤦♂️🤦♀️ |
I was demonstrating how an audio analyzer can measure inconsistencies between cables. When you have hands on experience rather than just reading what the clowns on ASR say you can learn a few things. I measure stuff all the time with balanced connections and the consistency is spot on. Pretty obvious from my replies AmplifierDude that I have more than enough experience when I can look at your numbers and know whether they are "real" or there is a flaw in them.
These were your exact words from Saturday, November 27, 2021. So you have become a measurement expert in the last 3 days? I stick to my previous comment. I do not think you know how to use your tools properly. Asking how to measure the audio band THD of a 15KHz reinforces that you do not understand the measurements (hint, there are 0 harmonics of 15Khz in the audio band, hence you cannot measure it). The last post even brings up your name. You may want to try to understand a multi-tone IMD test it will prevent saying things you may regret later. Will you grace us with your list of "measurements that matter" ? In respect of other people here, I will not respond to this more, as the thread is already off track.
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In case anyone cares, since Mike is too lazy to read the full test or understand the measurements, here is what is in it:
Has @mivmike never read past the first page or does he not understand the rest of the measurements? |
You just do not understand what you post. The Hypex graph above is at one power level, 5 watts or about 1% of it’s output. There is about a 15-16db change from 200-20Khz. I don’t know what is happening below 200, seems all over the map. Even at 5W, the Topping only has about a 20db change from 20Hz - 15KHz. That is not much different from the Hypex. If you test the Topping at 1%, or about 1W, then it has only about 2 or 3db change over 20Hz - 15KHz. That is quite a bit better than the Hypex. You could choose to stop posting stuff that gets holes blown in it. Or not. |
I could be your mentor if you took the time to understand what I am writing. Here is another mentoring for you. The Topping is -75db distortion at 5W, 15KHz. That is 0.017%. That is almost exactly the same as the Hypex at 0.015%. At lower frequencies, the Topping is even better than the Hypex. Of note, the ASR graph is 45KHz BW, so after about 10KHz, the THD will not be audible to anyone, and for most here I expect that will be the case at close to 7-8KHz. |
I admittedly read the graph wrong, however, you may want to reconsider making libellous statements like this:
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@mivmike -- you didn't even know how to use it 3 days ago, sure your stuff went up ... |
Don't expect to get respect from Bruno when he knows what he is talking about and you do not. Hysteresis in the inductor is just yet another form of non linear distortion, like any other distortion. If you apply negative feedback it gets reduced by a compensatory amount, and his amps have a lot of feedback because the can. The inductor is in the feedback loop, hence any hysteresis distortion is drastically reduced by the feedback. He is not saying it does not exist at some point in the circuit, he is saying that he effectively eliminates its audible effects, which is self evident from the distortion measurements. |
You really need too learn more, and type less. They Hypex modules have the inductor in the feedback loop. The Purifi are an advancement, but they are just "better" not architecturally that much different, not even the components are that substantially different. They are an evolution not a revolution. |
If you insist on being detached from reality then it will be impossible for us to have a meaningful conversation. Absolutely hysteresis will show up in a distortion test, especially any IM distortion test. It should be self evident. If it is not, there is not much i can do to help you. I suggest studying hysteresis more and perhaps modelling it in an electronic circuit. There are mathematical models that are half decent and that you could plug into spice and see what happens. Any distortion in the feedback loop is going to be influenced by negative feedback. that is what negative feedback does. It is analog error correction. And since you can measure the distortion before and after, especially IM distortion, it is very easy to know what the feedback does to the distortion. You not understand this does not make it incorrect, it just means you do not understand this. If you did the simulation, or even built a test circuit and measure it, you would see what the distortion products look like. From that, knowing the level and order of even and odd harmonics, you can relate how that may sound, from the tons of psycho acoustic studies into distortion, to the average person. This is science, but not rocket science. Again, you not knowing this does not make it not true, it just means you do not know it. I can't tell you specifically how any given person is going to behave to a specific distortion signature, but I can certainly make generalizations that will be highly accurate across a wider population of listeners. That is why we know added distortion, even added noise can result in pleasing listening impressions, or false sense or loudness, or harshness or .... Because while we are different, we are also very similar.
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@jerryg123 that is a rather toxic rant on your part and really unwarranted. By any measure, the Purifi modules set an incredible standard for state of the art in amplification not just at their price, but at almost any price. It's like photography. Bruno created an 100 megapixel camera, with super high dynamic range, incredible optical resolution, and perfect color rendering, and he did it for $2,000. Now some people are really offended by this, both because it is so much better than what they own, but also because the plebs can now own something better than what they have. They could just buy it themselves, but then that would require accepting its superiority. Then there are a different group of people who love, for whatever troubles it may have, the look of film, grain, inconsistencies, lower effective resolution and all. They like their colors a bit more vivid and skewing to red, and they like their images a bit softer. Bruno's new camera is not for them. Which photographer are you @jerryg123 ? |
@kuribo , it does not appear possible to have an adult conversation. That would require people to behave like adults. You tried. |
Great post! People think air core inductors are the messiah, but they can have serious consequences if not used properly. No doubt a large part of the reason for the "style" of inductor use by professional companies like Purifi/Hypex is the closed magnetic path resulting in little stray magnetic field. Drum core inductors are bad enough, and with an air core, that steel mounting screw, those resistor and capacitor leads, etc. are all now part of your circuit, let alone if a customer decides to use a steel case instead of an aluminum one, I would say very common due to the huge cost differential. For others, the reason for not using toroids is likely for many practical reasons. To get a specific inductance and saturation point in an inductor of a given size, that requires a specific number of turns and an air gap of a specific size. That is easy with many standard cores, one leg is just ground down typically fractions of a mm. That is very difficult with a toroid, and a side effect is the gap is now exposed (EMI, etc.) For that reason and a host of others including inflexible size/mounting, gapped toroids are rarely used. Most common toroids you see in power supplies / amps (not line/audio frequency transformers) are usually a ferrous powder or some similar magnetic material molded with a binder. The "gap" is distributed throughout the toroid. The problem with these materials is they tend to be pretty lossy at the upper end of their frequency ranges and are not overly linear w.r.t inductance versus current. Some toroids are ferrite, but you are limited purely in turns ratios w.r.t. usage.
p.s. to those who called me an "armchair/wikipedia engineer", this is me having the last laugh. |
@jaymark , thank you for indulging me with what speaker you are using. I don't know the Spatials other than from the web, so I can't comment too much, I know the Revels, and was able to find an impedance curve for them. Their impedance drops below 4 ohms for most of their higher frequency performance. With the LSA, one would expect a droop/shelving of the high frequencies starting about 5KHZ, and continuing to about 1.5-2db down (roughly) at 20KHz. If you still have pretty good high frequency hearing, and your room is "lively" i.e. not a lot of absorption/acoustic treatments, that could make the amplifier both sound less harsh to you, and by taking the emphasis off the high, give better weight to the bass. As well, though our high frequency hearing is not as good, it can present a masking function for lower frequencies, so it could, just by making this "less busy" at least to you, give a subjective impression of better midrange. Compared to a traditional tube amplifier, based on the measurements I saw, the LSA will have far far less intermodulation distortion, and this could also make the midrange come alive for you in comparison. I am curious what your impression are with the Spatial Audio X5s. There is no impedance data, but it is listed as 8 ohms, so I would expect it to roll off less in the highs compared to the Revel with this amp. From a purely "state of the art" perspective, the LSA is not near the top, though I think some of the specifications, like IMD, are pretty good. I can see though, in your particular case, and compared to other products you used, why this amplifier could be the best you have experienced. I am happy that you came across it. |
@ricevs , I don't mind aggression in a technical discussion, but you are just making up conclusions that stating things that show you don't know nearly as much as you think you know:
Floyd Toole, Stanley Lipshitz, James Johnson and a whole host of other people you have not heard of have spent their whole lives researching, often using blind testing, the impacts of audio reproduction and how that impact how we perceive sound. It is how we know about things like in-room response preferences, the important of flat on axis response, how we are more or less sensitive to some types of distortion, about masking functions w.r.t. frequency response, about limits of human hearing, about masking of quiet sounds by loud sounds, about audibility of jitter in digital playback, about perceptual impressions of noise, etc. And everything I have just listed in affected by the electronics. Assuming that the OP experiences an audible difference with the LSA amp and it is not just bias, and I am very much inclined to believe that he is experiencing it, it won't be explained by solder, or silver versus copper wire, or binding posts, or AC outlets, or power cords, it will be explained by real and significant differences. Those differences won't be explained in platitudes from audio reviews either. They will be explained by cold, hard science. The measurements on ASR of the LSA amp, and taking into account the impedance of the Revel speakers, and what we know, from extensive scientific exploration of audio, is what will explain it. We know from Toole's/Harman's extensive work on preference curves that people prefer something close to a in-room response that declines in output slowly from the mid-bass to the high frequencies. We know that excessive high frequencies make the sound harsh/bright, that they mask detail in the mid-range. We know that tubes amplifiers almost as a rule have lower damping factor that gets worse as frequencies go up, and that this will cause high frequencies to reduce in amplitude especially with a speaker like the Revel. Reducing the highs can remove an impression of harshness, especially in rooms that are highly reflecting, and that removes the masking function on the mid-range, allowing the mid-range to appear smoother. We know that Class-D amps have high damping especially in the bass, and that generally contributes to tighter bass compared to tube amps. Tube amps can have higher IMD which will impact mid-range / high frequency detail. The op stated that the LSA was like the best of all worlds, tube and Class-D/SS. I previously stated the characteristics of the Revel. The LSA has some defining properties. It has reducing damping factor at high frequencies. With speakers like the Revel, this will result in a fairly significant (1.5-2db) and audible reduction in high frequencies. The LSA like other Class-D has great damping factor at bass frequencies which will contribute to tight strong bass. The reduction of the highs will both reduce perceive harshness, and will reduce the masking by high frequencies allowing the midrange come across clearer. In addition, the LSA has very low IMD, which will further improve clarity in the midrange. No magic unproven hypothesis about minor components, just significant and real differences, yes explained by frequency response, damping factor and distortion. I will further add that frequency response will have by far the largest impact on imaging / soundstage, so an amplifiers interaction with a speaker, if it impacts frequency response is going to be by far the biggest contribution in the electronics chain to imaging/sound stage. Again, not solder, connectors, some wire in the amp, AC sockets, power cords, etc. |
Your statement above shows that you have spent 0 effort trying to understand how the LSA amp would behave with a real load, and especially with the ops speakers. Instead you insist on grasping onto things like solder or connectors, or ... and no they have not wasted time on a double blind test, because that is just what it would be, a waste. I think if you search long and hard, though you may find one on capacitors in a cross-over, but the result will not be to your liking. I have explained, in excruciating detail, how electronics, in this specific case, will absolutely effect listening impressions. I have brought you to the water, but I cannot make you drink. I believe Nelson Pass was just being polite. Anything he has put down to paper (i.e. on the record) has been backed up by actual data, i.e. he tackled the potential for frequency response variance with cables. He has never, to my knowledge, given credence to "tweaks", but he understands his customer base, so he knows not to put them down either. It would not be good for business. In terms of how distortion contributes to perceptions of sound, this is just every day common knowledge now (or should be if you are claiming to be an amp expert) including what we perceive as pleasant, unpleasant, how it may impact loudness impression, masking functions, etc. As always Google. |
This part of your post is just petty, angry, disrespectful, and inaccurate. |
@ricevs, the adult and mature response would be to admit that you are wrong and that we really do know a lot about distortion and how that impacts listening experience. The is not a "subjective listening forum". It is an audio forum. Those that refuse to learn are destined to repeat mistakes. If you refuse to learn the extensive things we know about sound and how that impacts our subjective listening impression or even to accept that that knowledge exists, then how do you ever hope to design products that more than a few people will subjectively like? You brought up Nelson pass before. He purposely creates amplifiers that do not accurately reproduce analog waveforms. Not all his amps do this, and not all do that in the same amount. He does this because he has done the work and studied what he can do to his amplifiers to create a better subjective listening experience with a target market. Not everyone likes his amplifiers and you may like one and not another. And because he did the work to find out what people subjectively like and how his amplifier can deliver it, all an "objective" exercise I might add, he is able to charge far more for his amps. There is nothing "tweaky" or "listened" to w.r.t the LSA. It is off the shelf modules in a box with performance as absolutely dictated by its architecture.
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@ricevs , I try to lead you to water, but I cannot make you drink. I don't think you are reading my posts or attempting to understand them, you are just responding in anger. A careful read of my posts will show that I have never once called you names, though you are giving me plenty of reason to do it. I choose not to stoop to your level. Even when provided ample proof that your claims are false, you still make aggressive, inaccurate posts meant to do nothing but denigrate like this one below. You have tried to take this posts about the LSA amp and make it all about you and what you do. I researched the product the OP is using, asked a question to fill in a piece of information I did not have, then analyzed how the two would behave together, and interpreted that based on extensively researched, well understood, and not remotely controversial aspect of subjective preference testing and psycho-acoustic testing. I presented my analysis in detail for others to discuss, refute, agree with, etc. How about you tell us what is going on with the OPs system?
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Bye bye @ricevs , I will reiterate, Nelson Pass was probably just being nice, but it is pretty obvious why he was not interested. I am done educating you. I regret the education I have already provided. I will accept that apology now though.
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Well that is interesting, considering that these are essentially variants on the GAn Systems Evaluation boards that Skip Taylor designed for GaN systems, but with some of the flaws fixed and now sold under his company name. Considering those came out about March 2020 and the LSA GaN was done in July 2020, that "couple years" comment is quite suspect. It does not "sounds" any particular way. The distortion while not state of the art (except for IMD) is below audible levels, so that pretty much puts us at how the output impedance goes up at higher frequencies resulting in speaker dependent objective and subjective differences. Mark Shifter also said this,
... which has about as much relevance to audio and amplifiers as saying "I like blue". Since you don't appear to have anything relevant or concrete to add to this conversation @ricevs, I will say good bye.
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The only one spreading hate, that i can tell is you. I keep my arguments to the topic at hand, while I people like try to denigrate me, and others with personal insults. You need to learn to practice what you preach. I will call out posts that are quite obviously wrong and a whole lot of those have been prevented in this thread. Seems I am the only one that even attempted to take a critical look at what is happening with this amp and the OPs setup. I am also not calling Nelson Pass, one of the most respected amp designers, essentially incompetent. That was someone else. I am also not complaining that decades of work on what sounds good does not exist. Bye Bye Jerry. Take your anger and hate elsewhere. |
