RF Attenuators = Jitter Reducers

Do you have a SPDIF transformer in your Digital Device

  • Yes

    Votes: 40 71.4%
  • No

    Votes: 16 28.6%

  • Total voters
    56
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Just looking at the posted result I cannot but feel "it smells very fishy".

Frankly, ThorstenL, your own protestations about NDRs and other issues making it impossible to do these tests yourself sound very fishy to me. You are perhaps a lab technician working somewhere they have this equipment, but they don't allow you to touch it?

Places where I worked trusted engineers to take equipment home when it was signed out. Time for you to put your money where your mouth is.

w
 
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Do you mean harmonic distortion? Is it that bad? H5, H7, H9 are higher than they should be, but it's a cheap 3 opamp circuit with an electrolytic coupling cap. Part of that "Behringer sound."

At that, they're below -110dB, and that's with the Behringer's gain backed off to accommodate the M-Audio. The audibility is questionable at best. I suspect that the "Behringer Sound" is more a function of the HD from higher frequency signals to which you directed me. There, you start getting stuff up in the -80dB range, which is a lot closer to plausible.
 
Hi John - I suspect SY is on a hiding to nothing here in terms of the listening test. I'd hasten to add that the hiding is probably not from you!

Its the old double bind dilemma - he KNOWS which device is which. Moreover his predilection following the measurements he has made is (I presume) to consider the outputs reasonably close if not identical in all practical sense.

As we all know, this will flavour the listening test regardless of any attempt at impartiality. It may even contribute to an exaggerated bias TOWARD the HIface as a subconscious response to a conscious knowledge of personal bias!

So, if he listens and returns a verdict of "no discernible difference" or "preference fort the cheap USB" he's clearly bias against the HIface device. Alternatively, if he finds for the HIface, its because he has attributed to it a degree of sophistication (the 192 capability) and knows its the more expensive. Or a positive bias as described above.

Its fraught, especially after a journey like this.

Which isn't advice to SY not to listen or respond - just a caution regarding interpretation of any views he may come back with.

You may be correct AArdvark,

And seeing as this thread has run it's course, let me suggest a DBT test in somebody's place that might be interested in hearing these two devices? I just suggest that you don't restrict the listening to one DAC & to avoid ASRC DACs if possible. If anyone is interested in doing this, I'm happy to pay for the shipping to them.

Any takers?
 
Hi,

Frankly, ThorstenL, your own protestations about NDRs and other issues making it impossible to do these tests yourself sound very fishy to me.

The NDA's are from the manufacturers of the devices/chipsets for USB Audio.

I can test and post anthing I like. I do not normally take the AP2 home though, not that anyone would mind, as I make the rules in that place, but it's to big and heavy. I can drop into the lab on saturdays or do it in the evenings.

What I cannot post are the results for devices for which I or the company has signed one of the extensive NDA's (which pretty much forbid even mentioning what you are testing) and which cover basically anything USB Audio currently known, excluding the Musiland stuff (we bought that off the shelf).

Ciao T
 
@ThorstenL

1. You are anonymous here.

2. If you feel you are not anonymous, that's what internet cafés are for.

3. You're not demonstrating a lot of ingenuity. If I wanted to prove a point I wouldn't be letting an NDA stand in the way. Ask for an exception. Disclosure in this case is hardly hurting anybody's interests, except perhaps jkeny's and yours. Or borrow the equipment and get a third party to perform the tests.

w
 
Re VSWR> 1st test should be to determine the Thevenin source/s. Measure Voh / Vol with an open circuit and compare to a known termination. The overshoot is related to XFMR leakage inductance V = Le*di/dt.
IMO HiFace didn't use a quality pulse XFMR. See post # 130 this thread
 
If I wanted to prove a point I wouldn't be letting an NDA stand in the way. Ask for an exception. Disclosure in this case is hardly hurting anybody's interests, except perhaps jkeny's and yours. Or borrow the equipment and get a third party to perform the tests.

Stuart Brand said:
Information wants to be free...

Remind me never to do an NDA with you.

Anon said:
Law is for the guidance of wise men, and the obedience of fools...

Consider yourself reminded.

w
 
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I did. The use of Latin spuirae in place of the English spuria is common in some writing concerning spurious electronic signals and is acceptable, but spuria is proper English. I find no use of spurii other than in Italian.

If you have a disagreement with the Oxford English Dictionary, maybe you should write a letter to the Times or to the Queen or somethng. :)

John
 
The use of Latin spuirae in place of the English spuria is common in some writing concerning spurious electronic signals and is acceptable

What do you think we're talking about here, gardening? If you want to argue dictionaries then look here: Spuriae - Definition and More from the Free Merriam-Webster Dictionary

If you want to see spurii used then look here: Variable-frequency oscillator - Wikipedia, the free encyclopedia

If you go and google spuria you will find a page full of references to a flower. In my opinion google is a more reliable guide to usage than any dictionary. YMMV.

I'll give you a point for owning an OED.

w

You lose it again for including that ridiculous little grinning yellow face.
 
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