Testing audiophile claims and myths

[jagwap]

Again, I do have those two differently sounding USB DACs (due to their amps definitely), and I still could not match the sound of my old DAP.
I do have many more USB DACs which may be harder to distinguish in some blind tesrs, but those two - easy. I also have the third one - ESS-based, but nothing like more common ESS sound due to its amp, it is made to be "analoguish" and has some background hiss which would make it unmistakably distinguished.
What do I need to prove there?

So instead of spending time trying to prove something to guys like you, I would rather wish to get some practical feasible advice, which this thread is hardly famous for, in my experience with it.

Another interaction is the size of the capacitor on the DAC output interacting with the amplifier input impedance. If the input impedance is smaller on one amp than the other, and the output capacitor is not large enough, one system will have higher phase shift at LF than the other. I know people who have proved this is audible. Likewise the output EMC capacitance on the DAC, adds to the input EMC capacitance on the amp input. If the accumulation of capacitance is different it will result in a different low pass filter when combined with the output impedance. A good design makes this negligible, which is not guaranteed unfortunately. More likely is the tolerance of the capacitors is not tight enough, the left and right phase shift will be different. If it is high enough it can effect stereo image.

 

[bigshot]

“Defective by manufacture or design”

Building a transparent amp isn’t rocket science. I’ve yet to run across one that isn’t. If anyone knows of an amp that is poorly designed to the degree of not being transparent, instead of speaking of it in theory, they should name the specific make and model so people can avoid it.

 

[PhonoPhi]

Thank you, all, a lot of good points to consider and think over, I will try to reply more specifically slowly.

I do not have problems that different USB DACs sound different because their amps, etc were designed differently - I take it now for granted.

It indeed took me sometime to realize that my old DAP was coloured, partially due to some idealistic dogma of "transparency" .
My problem was first being able to find the same/similar colour, and now to have some reasonable guide for it.

 

[PhonoPhi]

The path to practical feasible advice here is a concise focused question

While DAC colouring problem is hard to "focus", I do have a specific question that I tried to ask before and did not get an exact answer.
The question is about the limits of an Apple USB DAC to drive different IEMs in terms of their impedance. While the upper limit can be inferred from the voltage limitations, what would be the lower limit on the IEM impedance - I could not find specs.

 

[jagwap]

Thank you, all, a lot of good points to consider and think over, I will try to reply more specifically slowly.

I do not have problems that different USB DACs sound different because their amps, etc were designed differently - I take it now for granted.

It indeed took me sometime to realize that my old DAP was coloured, partially due to some idealistic dogma of "transparency" .
My problem was first being able to find the same/similar colour, and now to have some reasonable guide for it.

If you are looking for the same colouration that is tricky. Your best hope is to buy something from the same brand, hoping that is their in-house sound.

 

[jagwap]

While DAC colouring problem is hard to "focus", I do have a specific question that I tried to ask before and did not get an exact answer.
The question is about the limits of an Apple USB DAC to drive different IEMs in terms of their impedance. While the upper limit can be inferred from the voltage limitations, what would be the lower limit on the IEM impedance - I could not find specs.

It is usually a current limit. As you say they do not publish this.

If it is the standard lighting DAC dongle, many people tore it down and analysed it. If I recal the Cirrus part is a special part number for Apple, which doesn't help find a datasheet.

The current limit is usually the amount of current that the negative rail charge pump can supply, and this will often be frequency dependant. Low frequencies will drag more current from the switched capacitor network that creates the negative rail voltage than high frequencies.

 

[PhonoPhi]

If you are looking for the same colouration that is tricky. Your best hope is to buy something from the same brand, hoping that is their in-house sound.

Exactly, and trying to get the same/similar product would be the easiest solution.
I did realize it later, but at first I was not aware (could not believe) colouration.
My old DAP is Pioneer XDP-30R, which I tought of as ESS, but it has treble softened/smoothened that biased my IEM selection.

Since all sources were portable, their grounding is simpler being more limited than portable DACs

 

[Vamp898]

Thank you, all, a lot of good points to consider and think over, I will try to reply more specifically slowly.

I do not have problems that different USB DACs sound different because their amps, etc were designed differently - I take it now for granted.

It indeed took me sometime to realize that my old DAP was coloured, partially due to some idealistic dogma of "transparency" .
My problem was first being able to find the same/similar colour, and now to have some reasonable guide for it.

Or just get an THX AAA one, they are uncoloured.

If you like the uncoloured sound, THX amps are available in all sizes and forms. USB dongle, DAP, large desktop amp and so on

 

[PhonoPhi]

Maybe the difference with your ESS based DAC is the filter option used by its designer, (if it’s say the Sabre 9018) some manufacturers allow user switching between various filter options programmable by software on the chip itself, “slow roll off” akin to NOS maybe the one chosen for the “analoguish “ sound,
But that then begs the question, if another manufacturer uses a different filter option that sounds slightly different which option would be considered “audibly transparent” ?
Why, according to some, would a DAC chip manufacturer allow an option to switch between the “audibly transparent” option and three or more “broken” ones ?
Or maybe it’s just a matter of fine tuning to suit various output stage differences ?

A good point!
Filter option was enabled in X30 that is exactly 9018-based but then the amp was made to smoothen the glare and possibly to differentiate from other DAPs.

If to compare DACs/amps to a glass, the perfect non-coloured one would be hard.

@bigshot - It is not that brainy to to make "transparent" powered DAC, making portable one may be already a bit harder. Then DACs are made to be different, again similar to not being just "red wine" but different vintages.
Is this good or evil - another point.

 

[Vamp898]

A good point!
Filter option was enabled in X30 that is exactly 9018-based but then the amp was made to smoothen the glare and possibly to differentiate from other DAPs.

If to compare DACs/amps to a glass, the perfect non-coloured one would be hard.

@bigshot - It is not that brainy to to make "transparent" powered DAC, making portable one may be already a bit harder. Then DACs are made to be different, again similar to not being just "red wine" but different vintages.
Is this good or evil - another point.

As I always say, the best DAC is not having one in the first place. If you can life with the lower output power, full digital amps are the way to go. Why amplify an analog signal if you can just amplify the digital one.

Attention: personal opinion, not a fact

 

[bigshot]

If you are looking for the same colouration that is tricky.

It’s not tricky at all. The impression of coloration is likely a result of perceptual error and/or bias. As long as he doesn’t change that, just about any DAC will do.

 

[bigshot]

As I always say, the best DAC is not having one in the first place. If you can life with the lower output power, full digital amps are the way to go. Why amplify an analog signal if you can just amplify the digital one.

Attention: personal opinion, not a fact

Do you have a USB connection in the base of your neck? How do you avoid turning it into physical sound that your ears can hear?

Doh! (Head slap)

Here is the theme song for Sound Science tonight...

 

[jagwap]

As I always say, the best DAC is not having one in the first place. If you can life with the lower output power, full digital amps are the way to go. Why amplify an analog signal if you can just amplify the digital one.

Attention: personal opinion, not a fact

In theory yes. But fully digital amplifiers tend to be lower performance than current top end DACs in most respects. So turning that on it's head, it would be better to use a DAC with enough power to driver your transducer.

But at that point, they become the same thing.

 

[bigshot]

^ he didn't even notice the line, "the best DAC is not having one in the first place". Yeah, my headphones sound better with no DAC. And of course "lower performance" means a little bit lower performance, but still below the threshold of human hearing. If you don't do controlled listening tests, it's all just abstract numbers, not sound. Better numbers are better, right?! Not if those better numbers can't be heard. You end up chasing numbers down a rabbit hole and achieving nothing. There is such a thing as good enough. But with audiophools, too much is never enough. Meanwhile, better transducers and a corrected response curve could make improvements in fidelity that make a real difference.

Stick your head in the sand and block me now. All the snake oil salesmen beg you to do it.

 

[Dogmatrix]

While DAC colouring problem is hard to "focus", I do have a specific question that I tried to ask before and did not get an exact answer.
The question is about the limits of an Apple USB DAC to drive different IEMs in terms of their impedance. While the upper limit can be inferred from the voltage limitations, what would be the lower limit on the IEM impedance - I could not find specs.

Have you tried the AES this sounds a little beyond what is extensively an amateur enthusiast forum