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Woo Audio WA7 & WA7tp DAC and Headphone Amp Review

Julf

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The frequency response of everyone's hearing is different. For example, older people have a harder time hearing high frequencies. As a consequence, they might prefer a leaner or brighter sound presentation. Beyond obvious differences due to age, there is also a natural variability in hearing even in young people, which might affect their listening preferences.
So how do they get leaner or brighter sound at a concert?

Whether sound reproduction should or should not be coloured is something pointless to discuss IMO, because it depends on personal preferences.
Fine, as long as there is no pretensions of HiFi (as in "High Fidelity"). Some people might prefer boom boxes or 8-track...
 
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So how do they get leaner or brighter sound at a concert?
They dont.

Fine, as long as there is no pretensions of HiFi (as in "High Fidelity"). Some people might prefer boom boxes or 8-track...
I am sure that the several thousands owners of euphonic tube amplifiers across the world would argue that their system is still High Fidelity, but personally I am not much fussed by definitions
 

amirm

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I am sure that the several thousands owners of euphonic tube amplifiers across the world would argue that their system is still High Fidelity, but personally I am not much fussed by definitions
All that says is that audiophiles are terrible in hearing artifacts in reproduction systems. :) They think they are good at it but give them any controlled test and they fail it.

Here is the thing and there is no way of getting around it: measurement of an audio product follows accepted industry and research standards for proper audio science. Subjective listening by audiophiles, reviewers, etc. does NOT. So you can't rationalize the two. It is like trying to explain why someone says drinking tons of carrot juice cured their cancer.

In countless controlled listening tests, I either hear tube distortions as objectionable or not. If someone wants to provide me with a controlled test that says otherwise, I am all ears. Otherwise, the test does not follow accepted scientific protocol so can't be compared to objective measurement results.

I think in a narrow set of cases high output impedance of tubs amplifiers may modify the frequency response of either speakers or headphone to one's liking. Such cases are rare though compared to the adoption of tube products.
 

Veri

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All that says is that audiophiles are terrible in hearing artifacts in reproduction systems. :) They think they are good at it but give them any controlled test and they fail it.

Here is the thing and there is no way of getting around it: measurement of an audio product follows accepted industry and research standards for proper audio science. Subjective listening by audiophiles, reviewers, etc. does NOT. So you can't rationalize the two. It is like trying to explain why someone says drinking tons of carrot juice cured their cancer.

In countless controlled listening tests, I either hear tube distortions as objectionable or not. If someone wants to provide me with a controlled test that says otherwise, I am all ears. Otherwise, the test does not follow accepted scientific protocol so can't be compared to objective measurement results.

I think in a narrow set of cases high output impedance of tubs amplifiers may modify the frequency response of either speakers or headphone to one's liking. Such cases are rare though compared to the adoption of tube products.
This forum should have an equivalent to reddit gold :D great post, Amir.
 
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All that says is that audiophiles are terrible in hearing artifacts in reproduction systems. :) They think they are good at it but give them any controlled test and they fail it.

Here is the thing and there is no way of getting around it: measurement of an audio product follows accepted industry and research standards for proper audio science. Subjective listening by audiophiles, reviewers, etc. does NOT. So you can't rationalize the two. It is like trying to explain why someone says drinking tons of carrot juice cured their cancer.

In countless controlled listening tests, I either hear tube distortions as objectionable or not. If someone wants to provide me with a controlled test that says otherwise, I am all ears. Otherwise, the test does not follow accepted scientific protocol so can't be compared to objective measurement results.

I think in a narrow set of cases high output impedance of tubs amplifiers may modify the frequency response of either speakers or headphone to one's liking. Such cases are rare though compared to the adoption of tube products.
Agreed.
However, I find it difficult to assume that the well established, generalised appreciation of tube artifacts (by many people with this hobby) is a random by-product of incorrect audio reproduction. There is clearly a trend here, as in: tubes tend to make reproduction of audio signal "incorrect" in a way that many like. And what purpose does hi-fi serve, if not that of providing more pleasure to music listeners? :)

I realise that here we risk to enter the never ending debate of "what someone likes" vs "how things are properly done", and I will leave it just here otherwise and I will soon have to admit that it is OK to like pineapple on pizza, which I cannot do that because I am italian and treasure my passport.
:)
 

Frank Dernie

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I think in a narrow set of cases high output impedance of tubs amplifiers may modify the frequency response of either speakers or headphone to one's liking. Such cases are rare though compared to the adoption of tube products.
I think this is the main thing people hear when comparing a lot of valve amps to solid state.
Some SS amps have a high enough output impedance to alter the frequency response of the speakers, but almost all valve amps do, some by a big margin.
One thing that surprises me is "tube rolling" in hifi. It started off in valve amps for guitars, which players run into clipping etc. to get the sound they want. Since the behaviour of different valves in clipping varies the tube rolling gave them an opportunity to experiment with the sound effects they could get. In a hifi amp the valves are all (or should be) in the linear region of their performance so changing valves should make little or no difference, except maybe a bit of change in gain.
I suspect the whole tube rolling excercise is an excercise in the reassuringly expensive influence on the placebo effect.
 
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I think this is the main thing people hear when comparing a lot of valve amps to solid state.
Some SS amps have a high enough output impedance to alter the frequency response of the speakers, but almost all valve amps do, some by a big margin.
One thing that surprises me is "tube rolling" in hifi. It started off in valve amps for guitars, which players run into clipping etc. to get the sound they want. Since the behaviour of different valves in clipping varies the tube rolling gave them an opportunity to experiment with the sound effects they could get. In a hifi amp the valves are all (or should be) in the linear region of their performance so changing valves should make little or no difference, except maybe a bit of change in gain.
I suspect the whole tube rolling excercise is an excercise in the reassuringly expensive influence on the placebo effect.
This is very interesting, re tube rolling. I personally found profound differences in sound presentation when switching tubes, easily detected in blind testing.

Perhaps tubes in hifi are NOT used in their linear region?
 

Frank Dernie

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Perhaps tubes in hifi are NOT used in their linear region?
If they aren't they aren't being used for the purpose of high fidelity :)
I have some plug-ins with my digital recorder that emulate the transfer function of a range of valve amps and effects boxes, but these are all for sound effects. If they were transparent I wouldn't be able to tell f they were selected or not, which rather defeats the object, so all the valve effects I know of are audible sound changes. The the output of the recorder is audibly indistinguishable from the straight microphone feed with no effects plug-ins enabled.
 

Julf

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However, I find it difficult to assume that the well established, generalised appreciation of tube artifacts (by many people with this hobby) is a random by-product of incorrect audio reproduction. There is clearly a trend here, as in: tubes tend to make reproduction of audio signal "incorrect" in a way that many like. And what purpose does hi-fi serve, if not that of providing more pleasure to music listeners? :)
There are lots of people who really like a lot of salt and tomato ketchup on their food - but would you want to add a lot of salt and tomato ketchup to every dish in a michelin-star restaurant?
 

Julf

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Indeed. That was precisely my point.

I am sure that the several thousands owners of euphonic tube amplifiers across the world would argue that their system is still High Fidelity, but personally I am not much fussed by definitions
As an engineer, I realize how important it is to have good, solid definitions. Yes, most competently designed tube amps easily fulfill the rather lax requirements of DIN 45500 and descendant standards, but High Fidelity means accuracy - fidelity to the original signal (so lack of coloration and distortion).
 
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There are lots of people who really like a lot of salt and tomato ketchup on their food - but would you want to add a lot of salt and tomato ketchup to every dish in a michelin-star restaurant?
good analogy.
The fact remains that many people prefer tubes to SS. This is certainly in part because they "think" tubes sound better, without really doing any testing. However in part I think this is due to the fact that tubes do make poor recordings more palatable, in the same way that salt improves average food (let me leave the ketchup aside here, as I think it just makes everything worse). And reality is that there are many great records out there that have been poorly mastered. So "food" is not always from a Michelin-star restaurant, in fact more often than not it isnt, and a little salt goes a long way. I guess the point is to not overdo it.

I guess this is why I like to have both a tube (Woo Audio Wa8) and a SS option (Naim Dac v-1) in my set-up.
 
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Indeed. That was precisely my point.



As an engineer, I realize how important it is to have good, solid definitions. Yes, most competently designed tube amps easily fulfill the rather lax requirements of DIN 45500 and descendant standards, but High Fidelity means accuracy - fidelity to the original signal (so lack of coloration and distortion).
The fact they cannot "edit" the sound at a live concert does not mean they won't want to do that at home.
I am an engineer too, and clearly solid definitions are fundamental in our job, but they become a little less useful when we are talking about personal preferences.
 

THW

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I think the euphonic distortion of tubes adds a bit of decay and warmth, and smears transients just a touch.
the problem is that distortion, at least distortion that is harmonic in nature, isn’t euphoric nor does it add warmth. harmonic distortion adds spurious tones that have frequencies higher than the fundamental so there is no way additional harmonic distortion adds warmth unless you’re talking about a specific frequency band.
 
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the problem is that distortion, at least distortion that is harmonic in nature, isn’t euphoric nor does it add warmth. harmonic distortion adds spurious tones that have frequencies higher than the fundamental so there is no way additional harmonic distortion adds warmth unless you’re talking about a specific frequency band.
With "warm" I didn't mean with more bass. Maybe I should have said "fuller" sound?
BTW tube also often add a bit of bloom in the low end for the lower damping factor compared to SS.
 

Frank Dernie

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With "warm" I didn't mean with more bass. Maybe I should have said "fuller" sound?
BTW tube also often add a bit of bloom in the low end for the lower damping factor compared to SS.
The most significant thing a low damping factor (=high output impedance) is to alter the frequency response of the speakers
 

Frank Dernie

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Thanks. Does this not often translate in bloomier/slower bass? Or is this another myth?
It may, but the main reason for less-than-clear- bass on valve amps is likely to be compromise in the output transformer design, very difficult to get a transformer to be good over the whole audio frequency range I believe, and ones good in the bass are big and expensive.
I am no expert though.
 

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