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Blind Test Results: Benchmark LA4 vs Conrad Johnson Tube Preamp

pma

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The LA4 certainly isn't "lacking" anything. It's just transparent. But I could say it does 'lack' certain things in the sense of comparison to the CJ tube preamp.

There is a big question. This question is if the human hearing process does really prefers the "technically perfect" recording and sound reproduction. I am not sure. Based on the experience how the uncertainty like vinyl groove noise or tape hiss and other tape species lead to usual listening preference, I would rather say that the technocratic perfection does not go hand in hand with listener's preferences.
 
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There is a big question. This question is if the human hearing process does really prefers the "technically perfect" recording and sound reproduction. I am not sure. Based on the experience how the uncertainty like vinyl groove noise or tape hiss and other tape species lead to usual listening preference, I would rather say that the technocratic perfection does not go hand in hand with listener's preferences.
I absolutely agree, and that is the big question. Do most people like an absolutely technically perfect recording, and do they like a flat frequency response? I’d argue that most people do not prefer either, or at least the latter, including myself.

I’m so used to listening to my two channel with subwoofers on, that it’s what i like. Is there anything wrong with that? Probably not, and also who am I to push my audio likes and dislikes on anyone.

I’ve never measured anything at my MLP except levels, and I know that I have some boomy bass to a certain extent.

So the saying different strokes for different folks, is true.

But my gear needs to measure well, my serious gear, and we’ll leave the vinyl side of it out of that.
 
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MattHooper

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I can't say with certainty if @MattHooper 's test was done with a level of rigor and precision that would pass peer-reviewed scientific muster. But Matt was open about the fact that this was a best effort and he himself is not claiming that level of scientific validity.

With that out of the way, I don't know with certainty if Matt's results are meaningful, but I am inclined to believe they are. They are consistent with what many folks have reported over many years about the sonic signature of some tube gear - and crucially, those reports seem to have a degree of consistency regardless of whether people prefer the tube sound or the non-tube sound. There are also a number of potential factors that could sensibly contribute to what he heard: the distortion of the CJ amp, the high-frequency response, and I suppose also things like output-input impedance of the CJ-Benchmark connection and the simple fact that he was actually listening only for the additive effect of the CJ being put into the chain, rather than comparing just the CJ with just the Benchmark.

So it's only one data point, and it's not conclusive, but I find it a heck of a lot more probable, and therefore more useful. than 99% of the other listening impressions/tests that folks post on audiophile forums.

Thanks Matt!

I appreciate the nuanced post tmtomh!

I think you've captured my own view of the results.

We can't all have the Absolute Answers to everything, even in the realm of audio, so our individual views are going to be influenced by what we read and also very much by personal experience. If for instance you have personal experience blind testing AC cables and finding no sonic difference (as I have) that (along with technical arguments) is going to influence your attitude towards the prospect they likely sound different.

Similarly, if one has done blind tests on their own gear (e.g. tube amps) and found no detectable difference, that's personal experience is going to strongly influence their view of these things.

It's one reason why even engineers can disagree - whether it's the "best" way to design a motorcycle, boat, turntable or speaker or whatever, there will be technical agreements and disagreements, but the scope of one's personal experience even as an engineer - little epiphanies along the way when you've tried certain designs - will lead you down one path, another person down another. (This is what I've observed in seeing many discussions among technically knowledgeable folks).

Since most of us cannot strictly test everything we do, pragmatism means we are often making choices based on non-scientific-level inferences. That's different from 'anti-scientific' which I take to be coming to overconfident beliefs that actually contradict our best science. In other words: "tube preamp sounds a little different? Eh...could be." "Expensive HDMI cable upgrades the sound/picture on your TV vs a competently designed cheap HDMI cable?" Sorry...that's not how HDMI actually works. Even if I felt I saw a difference I'd want more rigorous confirmation. And in fact, I did that for a range of cheap to expensive video cables years ago - blind tested, also with other participants - no difference.

On the other hand, in the 90's I was told that the differences I seemed to hear between some DACs/CDPs I owned shouldn't be there. So I blind tested them, using the method suggested by the skeptics, and easily identified between them. What to do with such "data?"
Well, the skeptics, and I understood their skepticism (the reason I did the blind test was due to my own skepticism!), could always say "Well, even if we can't find a problem with your method, we weren't there and you could have screwed up somehow." Fair enough. I was there, was familiar with how we did the test, and could not find any likely flaw at all. So I tentatively accept the results and move on, people reading the results could make their own assessment.
 
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MattHooper

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BTW tmtomh,

As to your hunch based on a level of consistency about "tube sound"...I agree...to a degree. It's a sort of "where there's smoke there might be fire" idea. The problem is, as we know, that exact same idea can be, and has been used to support all sorts of nonsense claims, from pseudoscience medicine, to new age healing crystals, to nutty audio tweaks. So if we are being rigorous we're going to want to hold that in suspicion. But of course...sometimes there IS fire where there is smoke. So the fire can't be ruled out unless perhaps one has very strong theoretical/technical arguments against it. And, having observed many discussions about tube gear among people who know this stuff, seeing some disagreements, I don't see the type of consensus "tube amps don't sound different from solid state or from one another" like there is for, say, the fact expensive HDMI cables can't alter the signal. (In fact I've seen many people with audio engineering knowledge rail against tube amps BECAUSE you may get audibly less accurate sound).

So in to this wiggle room, personal experience/perception sure feels compelling. For instance, I'd tried various solid state and tube amps back in the 90's until I landed on the CJ Premier 12s I still own. When I read Michael Fremer's sonic description of those amps, from his review, it blows me away. It is so "accurate" to the sound I perceive from those amps relative to others I've tried, it's like he's taken my sonic impressions and put them perfectly in to words.

This portion for instance: "though the upper midrange exhibited a rich, golden bloom—a sonic bouquet—too subtle to be called a coloration but sufficiently pronounced to enrich brass, strings, female voices, alto sax, and hall ambience with an intoxicating glow."

That is just precisely the character I hear from the old CJ gear, and which I have tried to describe with the CJ preamp. Bang on.
And the "CJ golden glow" to the sound was described over and over in reviews and by people who owned their gear back in the classic CJ days. So admittedly, that my own impressions (including the blind test) match the descriptions/reputation so well does lead me to the hunch of "there's fire in that smoke....there is something of a CJ sound to their classic gear."
 
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MattHooper

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There is a big question. This question is if the human hearing process does really prefers the "technically perfect" recording and sound reproduction. I am not sure. Based on the experience how the uncertainty like vinyl groove noise or tape hiss and other tape species lead to usual listening preference, I would rather say that the technocratic perfection does not go hand in hand with listener's preferences.

I'm very wary of coming to brorad conclusions through anecdote that "people tend to prefer X distortion." (And I'm sure you agree).

I mean, anecdotally, I've had differing opinions with people listening to the same system.

Take for instance the distortion in vinyl that often hear some find "pleasing."

My brother-in-law, an audiophile definitely on the "ASR" side of the ledger. He'd stored away his records and I asked if I could take them to my place. He didn't care about them and was baffled as to why I was listening to records. Scratchy, old tech, why in the world? He still listened to those albums, but via his ripped CDs or streaming.

When he came to my place I played some of his records and he was taken aback, said he never knew records could sound that amazing.
On the other hand, there was at least one or two (prog rock) records where we differed. We both agreed on the different character of the sound between the vinyl and digital, except he preferred the digital, whereas I slightly preferred the record. But I could easily hear why he preferred the digital.
 

DavidEdwinAston

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I'm very wary of coming to brorad conclusions through anecdote that "people tend to prefer X distortion." (And I'm sure you agree).

I mean, anecdotally, I've had differing opinions with people listening to the same system.

Take for instance the distortion in vinyl that often hear some find "pleasing."

My brother-in-law, an audiophile definitely on the "ASR" side of the ledger. He'd stored away his records and I asked if I could take them to my place. He didn't care about them and was baffled as to why I was listening to records. Scratchy, old tech, why in the world? He still listened to those albums, but via his ripped CDs or streaming.

When he came to my place I played some of his records and he was taken aback, said he never knew records could sound that amazing.
On the other hand, there was at least one or two (prog rock) records where we differed. We both agreed on the different character of the sound between the vinyl and digital, except he preferred the digital, whereas I slightly preferred the record. But I could easily hear why he preferred the digital.
Hold on, hold on Matt. Why could you easily hear why he preferred the digital? Sorry, how could you?
 
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MattHooper

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Hold on, hold on Matt. Why could you easily hear why he preferred the digital? Sorry, how could you?

I'm not clear on exactly what you are asking. If you mean "how did we compare?" we had listened to mix of records and digital source that night. I remember it was a Tangerine Dream record he really liked, that he listened to still on digital, that he didn't care for on vinyl. I can't remember if for that one we did a direct comparison right there (so I can't remember if his negative impression of the vinyl was based on his memory of listening to it on digital, or if we directly compared. My memory is fuzzy there). But as I said, we listened to both vinyl and some digital tracks. I know I personally compared the digital vs vinyl versions and could see why he'd prefer the digital.

If on the other hand you are asking "how could I hear why he'd prefer the digital, if in fact I preferred the vinyl?" It's simply that I recognize people like different things. When I compare digital and vinyl I usually hear some superior aspects in the digital version, but some things I like in the vinyl version. And I can see why one person may prefer one or the other. Just like I like Rush, but completely understand why my wife hate's the band. :)
 

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And I can see why one person may prefer one or the other. Just like I like Rush, but completely understand why my wife hate's the band. :)
All women hate Rush. Want to lose a girlfriend, make her listen to 2112. I’ve been to see them live 3 times. All dudes. I don’t care what side of the fence you’re on about tubes vs SS. This is 100% irrefutable truth. :)
 
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MattHooper

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All women hate Rush. Want to lose a girlfriend, make her listen to 2112. I’ve been to see them live 3 times. All dudes. I don’t care what side of the fence you’re on about tubes vs SS. This is 100% irrefutable truth. :)

Agreed. Attended many Rush concerts, same demographic. My anecdotes are irrefutable proof :)

(Though, actually, it seems in their later career that demographic expanded a bit. Especially in other countries. I seem to remember the audience in videos of their massive, manic brazil crowd had a suprprising number of females, IIRC. So maybe it's also a bit of a country-by-country thing).
 

DavidEdwinAston

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I'm not clear on exactly what you are asking. If you mean "how did we compare?" we had listened to mix of records and digital source that night. I remember it was a Tangerine Dream record he really liked, that he listened to still on digital, that he didn't care for on vinyl. I can't remember if for that one we did a direct comparison right there (so I can't remember if his negative impression of the vinyl was based on his memory of listening to it on digital, or if we directly compared. My memory is fuzzy there). But as I said, we listened to both vinyl and some digital tracks. I know I personally compared the digital vs vinyl versions and could see why he'd prefer the digital.

If on the other hand you are asking "how could I hear why he'd prefer the digital, if in fact I preferred the vinyl?" It's simply that I recognize people like different things. When I compare digital and vinyl I usually hear some superior aspects in the digital version, but some things I like in the vinyl version. And I can see why one person may prefer one or the other. Just like I like Rush, but completely understand why my wife hate's the band. :)
Thanks Matt. It was your second response that I was enquiring about. If you can understand that I would prefer Vinyl not to be discussed on ASR, while admitting that isn't reasonable, we will have a complete understanding!
 
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MattHooper

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Thanks Matt. It was your second response that I was enquiring about.

Glad I could help.

If you can understand that I would prefer Vinyl not to be discussed on ASR,

Ok, I do understand that would be your preference.

while admitting that isn't reasonable,

I admit it isn't reasonable.

I think ASR is more about education and discussion on how audio gear really works. With this information people can weed their way through the bullshit and make advised decisions with their money. But it's not about dictating what people can or should purchase or enjoy. My understanding is most here share this view.

If, for instance, you want to play vinyl as well as digital, you are more likely to find accurate information here on how to maximise that goal. It's why there is a section of the ASR forum devoted to vinyl playback. If you think that shouldn't be discussed on ASR, perhaps take it up with the forum owner?

we will have a complete understanding!

I guess we do. :)
 

DavidEdwinAston

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Glad I could help.



Ok, I do understand that would be your preference.



I admit it isn't reasonable.

I think ASR is more about education and discussion on how audio gear really works. With this information people can weed their way through the bullshit and make advised decisions with their money. But it's not about dictating what people can or should purchase or enjoy. My understanding is most here share this view.

If, for instance, you want to play vinyl as well as digital, you are more likely to find accurate information here on how to maximise that goal. It's why there is a section of the ASR forum devoted to vinyl playback. If you think that shouldn't be discussed on ASR, perhaps take it up with the forum owner?



I guess we do. :)
Smashing response Matt. And quite pithy, by your standards!
 

Gorgonzola

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.... They are consistent with what many folks have reported over many years about the sonic signature of some tube gear - and crucially, those reports seem to have a degree of consistency regardless of whether people prefer the tube sound or the non-tube sound. There are also a number of potential factors that could sensibly contribute to what he heard: the distortion of the CJ amp, the high-frequency response, and I suppose also things like output-input impedance of the CJ-Benchmark connection and the simple fact that he was actually listening only for the additive effect of the CJ being put into the chain, rather than comparing just the CJ with just the Benchmark.

So it's only one data point, and it's not conclusive, but I find it a heck of a lot more probable, and therefore more useful, than 99% of the other listening impressions/tests that folks post on audiophile forums.

Thanks Matt!
Thanks Matt, indeed, and thanks @tmtomh.

I have communed with audiophiles for 50 and especially in the last couple of decades the consistency of impressions of sound signature, as mentioned by tmtomh, has become very apparent to me. Congratulations, (once again), to @MattHooper for undertaking a blind comparison of two very different preamps.

What has disappointed me most about ASR -- or more precisely a certain set of members -- is the denial of that consistency of impressions. (Sorry, but I have called them denialists). Instead of acknowledging the probable validity of these consistent impressions, they dismiss them out of hand as based entirely on popular bias.

The denialists, instead of using science as currently constrained to justify their POV, would better serve audio science, especially psycho-acoustics, by applying their touted science to understand and quantify those many thousands of consistent reports of sound signature differences.
 

MarkS

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My claim (which I think would be the standard ASR claim) is that if there is an audible difference, then there is a measureable difference.

So in this case, step one would be to measure the frequency response of the two preamps. My bet is that there is a measureable difference there, one that would plausibly account for the audible difference.

My first problem with the subjectivist camp is that many of them claim audible differences in situations where this is just flatly physically impossible (eg, power cords, little wooden disks, etc.). So I don't trust them to get it right even when there may be real audible differences.

My second problem is that, even when these audible differences exist, they are often just due to a small frequency-response alteration, one easily predicted by basic electrical theory (e.g., total resistance in a speaker cable), and not due to some audiophile woo-woo design.
 

lashto

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Hey folks, I thought I'd post about a little blind test I did between my two current preamplifiers:
Benchmark LA4
vs.
Conrad Johnson Premier 16LS2 tube preamplifier.
cool test, thanks for sharing.

I guess some might argue that you chose two 'extremes' with the super clean Benchmark vs. the ~50 SINAD CJ.

So, here's another blind/controlled test from Tyll's innerfidelity with more similar devices. A trio of amps which were popular around 2015: one tube and two SSes. IIRC, they all measure in the 80-90 SINAD ballpark. Even so, (at least) one guy was able to ABX them quite fast
...I swapped the cables and he began to listen. Within a minute he identified first the Bakoon and then the Teton, leaving the Moon as the remaining amp—three for three first shot. Sheesh. Let's make that one count and see how you do. He missed one on the next trial, and then aced three in a row. Basically, a 14/15 score.
 
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lashto

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My claim (which I think would be the standard ASR claim) is that if there is an audible difference, then there is a measureable difference.

So in this case, step one would be to measure the frequency response of the two preamps. My bet is that there is a measureable difference there, one that would plausibly account for the audible difference.
If there is any audible difference, it should appear in some measurement/graph. That is pretty much for sure.

But I do not understand why 'everyone' on ASR is so convinced that any audible difference should be found on the FR measurement. HD/IMD, noise, crossover and other types of distortion are also audible. DBT proven and all.

Ok, FR is (by far) the first thing to look at. But there are many other measurements to check for audible traces. In this case, there is a gigantic SINAD difference between the ~120 Benchmark and the ~50 CJ. It would have been a surprise if that was not audible.
 
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MattHooper

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In this case, there is a gigantic SINAD difference between the ~120 Benchmark and the ~50 CJ. It would have been a surprise if that was not audible.

And one reason that is interesting to me concerns how subtle the difference is, given the much poorer measurements of the CJ preamp.

Yes the differences seem to me to be distinct, and for my goals they are significant. But in the bigger picture they are very subtle. Most of the super fine detail heard through the Benchmark is heard via the CJ preamp as well. Recordings retain their very individual characteristics. In that sense it could be surprising how alike they sound!

This is why I'm not just concerned with measurements but in the end result in terms of what I do or can perceive. It's like someone making a technical case against vinyl records relative to CD "vinyl can't do dynamics or bass or highs or a low noise floor or accuracy" like CD. Which is technically true. But I could be easily lead just on this emphasis on the "obvious technical superiority of CD" to conclude vinyl will sound like crap compared. Yet when I spin my records I'm often gobsmacked by the sound quality, even when I can compare to the CD version. Highs, bass, dynamics...it all seems there, at least in terms of my perception, and then it feels like a bit of a mountain was made out of a molehill, via the technical arguments.

Likewise it's possible one could come to expect a low SINAD preamp wouldn't pass on the sonic information in a recording very well...and yet...that too would seem to be an exaggeration when it comes to actually listening.

Likewise, I would expect many people reading my description of the "obvious differences" between the Benchmark and CJ preamp would have a different reaction. Even if they listened in my system and the did manage to detect a difference, I'd expect many to shrug their shoulders at the difference.
 

charleski

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So, here's another blind/controlled test from Tyll's innerfidelity with more similar devices.
But that account is wildly unconvincing. I read through it twice and still have no idea what they were actually doing. It's a cool story, but a real controlled trial needs to be a lot more rigorous.

Unfortunately a lot of audiophiles seem to think a DBT involves inviting some friends round for beers while you swap cables...
 

lashto

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But that account is wildly unconvincing. I read through it twice and still have no idea what they were actually doing. It's a cool story, but a real controlled trial needs to be a lot more rigorous.

Unfortunately a lot of audiophiles seem to think a DBT involves inviting some friends round for beers while you swap cables...
You need to read the whole Big Sound 2015 series, 10+ articles IIRC. It explains the whole setup and all the tests. Tyll was a pretty rigorous measurements guy not some wild "audiophile". His measurements for all the tested amps.

Also, 4-5 other people did the same tests and only that guy aced all of them. An unexpected surprise for 'everyone', including the organizer(s) but no one was able to find flaws...

Edit: updated the webarchive links, hope they work now
 
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charleski

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You need to read the whole Big Sound 2015 series, 10+ articles IIRC. It explains the whole setup and all the tests. Tyll was a pretty rigorous measurements guy not some wild "audiophile". His measurements for all the tested amps.

Also, 4-5 other people did the same tests and only that guy aced all of them. An unexpected surprise for 'everyone', including the organizer(s) but no one was able to find flaws...
Read what? It’s all been taken down and Hertsens didn’t bother to link to the post describing his methods, so finding it would require scrabbling around in the archive (neither of your links have been stored on Wayback). He doesn’t say that he used the same procedure as earlier, so we’d just be making an assumption anyway. All we’re left with is a cool story.

Maybe this guy does have preternatural auditory discrimination and can resolve very subtle differences. That in itself would be interesting and definitely worth investigating further in a rigorous manner. But … no, he doesn’t bother. It’s just an anecdote that he used for a blog post, and as worthless as all the other anecdotes littering the web.
 
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