# Serious Question: How can DAC's have a SOUND SIGNATURE if they measure as transparent? Are that many confused?

#### solderdude

##### Grand Contributor
Just responding. I want to stop.

#### mansr

##### Major Contributor
Just responding. I want to stop.

#### Holdt

##### Senior Member
It takes two to tango. We'll stop.

#### SIY

##### Master Contributor
Technical Expert
Yes, DF being a product of output impedance and load impedance (cables included). Worsens with low impedance loads. My calculations with an amplifier with DF=10 and a 4-2 ohm load, 13 ft 14 AWG cable returns an attenuation of max. 3.12 dB. 18 AWG returns 3.42 dB error.

DF = 160 returns an error of 0.9 dB (18 AWG)
DF = 80 returns an 1.1 dB error (18 AWG)
The math seems off.

#### sq225917

##### Major Contributor
A very unstiff power supply regulation for an OP-amp : slightly higher distortion at full music levels, current clipping in extreme cases, possible lower power voltage driving the OP and for sure some minor compression sound effects . In the original Linn akurate DS the output OP amps lm4562 only have 9 volts because of this - read more here:

They had only 9v feeding them because that's the voltage linn had to play with given the penny pinching decision to continue using one of their existing smps, it wasn't a musical choice, it was a fiscal one.

#### Tangband

##### Major Contributor
They had only 9v feeding them because that's the voltage linn had to play with given the penny pinching decision to continue using one of their existing smps, it wasn't a musical choice, it was a fiscal one.
I doubt it was the reason . Its a very expensive player. They use a very soft power supply ( If you read the whole modification thread you will understand.) The reason for this is probably to gain less noise, and (maybe) to have a softer more mellow sound. The power supply in the Akurate DS is so soft it collapses from 16 V to 10,6 volt , and after the regulator its only 9 volt.

”and I did some measurements on his Akurate DS. The situation is more difficult than I thought. First of all, it is actually clear what needs to be done. I count on:
The clock fraction looks decent, but the power supply of the clocks can clearly be improved - this power supply is quite crucial for the achievable cleanliness of the clock signals.

The exit stages. Oh man, same drama as in the O-Sneaky. Although LM4562 are already in there as OPs (good!), but then 300 ohms output resistance :roll: . Sure, there have to be output buffers. However, six pieces, two for the asymmetrical outputs and four for the symmetrical. The assertion in the audio test that discrete output buffers with Mosfets came after the OPs is a clear misinterpretation by the author: Both in the Akurate DS and in the Akurate DS/1, the Mosfets are only responsible for muting. This also applies to the Majik, which has the same circuit board but is not fully populated.

The RCA outputs of the O-Akurate are simply fed from the OP output, which is responsible for the positive half of the symmetrical signal. That's half-assed. That the RCA output is supposed to be the better one, as is sometimes claimed in the Linn forum (I'm not reading along there, but I was told that) is, from a technical point of view, sheer nonsense. You then only hear with half of the built-in DA converter. If you don't want to neglect the cinch outputs, you would have to do it like this: Take the symmetrical signal, calculate the difference with an OP and then feed the outputs via their own output buffers.

The output stages of the Akurate DS are only supplied with +-9V. That's a bit little in my experience. Above all, the output buffer should be supplied with at least +-12V. And there lies the problem: The original power supply does not supply enough voltage. In standby it's -19V and +16V, which come from the power pack (was already a dynamic or whatever the newer name is). But they collapse to -13.8 and +10.6V when the Akurate is turned on. This is just enough for the positive supply half so that the low-drop regulator (LM2941) can still work with the remaining difference of 1.6V. The power pack is designed to be extremely "soft". If I branch off 6x 15mA for the six buffers, 20mA for the clocks and 10mA for a double OP, i.e. a total of 120mA, the voltage of the power supply, which is much too meager for my taste, collapses completely.
Now you could say, ok, you need your own power supply for the additional installations. There's enough space in the case. However, this approach would torpedo the Linn concept that no 50Hz mains hum occurs in the electronics housing because the completely encapsulated switched-mode power supply already supplies DC voltage to the electronics compartment.”
——————

my thoughts:
I have tested driving lm4562 and the opa2604 with low voltage and the dynamics are clearly better with 15 volt. This is my (limited) experience .

Last edited:

#### SIY

##### Master Contributor
Technical Expert
I have tested driving lm4562 and the opa2604 with low voltage and the dynamics are clearly better with 15 volt. This is my (limited) experience .
Uh huh.

#### Thomas_A

##### Major Contributor
Forum Donor
Thanks, but no need for Google Translate - I have no problem reading Swedish. That picture doesn't help us much. Sure, it is a standard before/after switching setup, but it doesn't tell us anything about how levels were matched, and if the listening was single or double blind, or what statistical controls were used.

As an anecdote: When I participated (I think around year 1999) , the levels were matched +/- 0.01 dB at 1 kHz. A double-blind test between two CD-players, Denon DCD655 (from year 1999) and HK7600 (from year 1991). Testing place was Studio Blue in Stockholm. One person from the US had promised to travel to Sweden and join as a controller (from former AudioReview Forum) but he never showed up. The test itself was a real pain since it was not an ABX, but an AB-test with an initial training session. So no opportunity to switch and compare during the test. One person switched cable connections (hidden) according to a random scheme, and exited the room. Two other persons entered the room and one was the preamp switcher, and the other the listener. When the listener had decided, it was written down. The procedure was done 13 times. 11/13 correct.There was a short write-up published and some hot discussion about the results at AudioReview.

Other tests when I was there were always level-matched, but single-blinded (the switcher was however always out of sight of the listener). I would say that there were some doubts on that method, but some persons could really nail the correct source in consecutive series (more than 12-15 switches).

A final note is that the before-and-after test is not applicable on the CD-player test. I am also not aware of how current listening tests are performed; the above session occurred more than 20 years ago.

#### krabapple

##### Major Contributor
Apologies if any of this ground has been covered .. I admit have not read the full thread.

Gee, who could have guessed? There's your fundamental mistake right there.

And then you doubled down, spewing out all sorts of old, discredited audiophile nonsense arguments. Thereby provoking the usual helpful responses that you proceed to ignore/dispute with more nonsense. Even your wife could hear it. And then, the argument from authority: you've been a sound engineer, so.

Same old same old.

tl;dr: Apologies not accepted.

#### Trell

##### Major Contributor
Gee, who could have guessed? There's your fundamental mistake right there.

And then you doubled down, spewing out all sorts of old, discredited audiophile nonsense arguments. Thereby provoking the usual helpful responses that you proceed to ignore/dispute with more nonsense. Even your wife could hear it. And then, the argument from authority: you've been a sound engineer, so.

Same old same old.

tl;dr: Apologies not accepted.

You've too high expectations on his reading comprehension skills.

#### Killingbeans

##### Major Contributor
Now you're just being mean...

But yeah, if I got a dollar for every time someone came to ASR and said "If you just use music instead of test tones, all discrepancies will vanish!", I wouldn't need a job.

#### krabapple

##### Major Contributor
I think they tend to say rather the opposite: ""If you just use music instead of test tones, all discrepancies will appear!"

#### Killingbeans

##### Major Contributor
Both.

"The discrepancies between claims from golden-eared audiophiles and objective data will vanish! AND the discrepancies between the infinite complexity of audio and conventional test procedures will appear!"

#### firedog

##### Senior Member
The Schiit people (and others in blind testing) have shown results where they can tell DACs apart, for instance the 3 models of the Yggy DAC. Schitt claims they do tune the DACs with various parts. For instance to alter the sound of an ESS DAC so it fits the sound they want better than it would otherwise.

Source?

#### Blumlein 88

##### Grand Contributor
Forum Donor
The Schiit people (and others in blind testing) have shown results where they can tell DACs apart, for instance the 3 models of the Yggy DAC. Schitt claims they do tune the DACs with various parts. For instance to alter the sound of an ESS DAC so it fits the sound they want better than it would otherwise.
It is a nice story. Does it belong in fiction or nonfiction?

#### Mr. Widget

##### Addicted to Fun and Learning
DACs all sound the same... NO. All decent modern DACs sound imperceptibly similar. OK.

There is no reason to spend tens of thousands of dollars on DACs unless you are on a mission to keep the economy going. Agreed.

We have had DACs in our systems for about forty years now. A twenty year old DAC can be excellent, but it can also be measurably and sonically inferior to a modern DAC. The digital and analog circuitry in a USB stick DAC is measurably and audibly inferior to a typical high quality DAC so when people say all DACs sound the same, there should be some qualifiers.

Els

#### tonycollinet

##### Major Contributor
DACs all sound the same... NO. All decent modern DACs sound imperceptibly similar. OK.

There is no reason to spend tens of thousands of dollars on DACs unless you are on a mission to keep the economy going. Agreed.

We have had DACs in our systems for about forty years now. A twenty year old DAC can be excellent, but it can also be measurably and sonically inferior to a modern DAC. The digital and analog circuitry in a USB stick DAC is measurably and audibly inferior to a typical high quality DAC so when people say all DACs sound the same, there should be some qualifiers.
No one says all dacs sound the same - there already is a qualifier.

All dacs (here is the qualifier) that measure as audibly transparent - sound the same.

That is pretty much all of them in the blue and green sections of the chart here.

#### firedog

##### Senior Member
Schiit ran blind listening tests of the 3 models and some listeners could tell the DACs apart. They publicized it, I'm sure you can find it if you are interested.

#### Jim Taylor

##### Major Contributor
Forum Donor
Schiit ran blind listening tests of the 3 models and some listeners could tell the DACs apart. They publicized it, I'm sure you can find it if you are interested.

That's not the way it works here. To make a statement without providing proof, and then expect someone else to provide for you is not good form ..... not at all. If you make an assertion, it is incumbent on you to provide the proof (or link).

Jim

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