RF Attenuators = Jitter Reducers

[jkeny]

Thanks George,
Following on from my previous PS scope shot, here's one so far unseen - this is based on removing the 5V USB supply & replacing with a 5V battery as well as powering the laptop with a bench supply (the previous shot was using a Dell Inspiron laptop powered by it's PS brick & the 5V being supplied from USB). Sorry for the quality

[SY]

Originally Posted by jkeny

I would concur with this view - I would query the wisdom of using such DACs as the listening devices. The Benchmark DCX2496 has been analysed & found wanting. I would wonder about listening to a PC DAC. Sy, you might want to address these?

Well, first, I don't have any equipment from Benchmark. Mistyping on one of our parts?

Second, both of the DACs I actually use measure better than -115dB to the noise floor and THDs below 0.002%. They sound excellent when the gain structure is set competently. One local musician (who is uncharacteristically interested in sound and sound technology) was so delighted with the sound, he's insisting that the mastering of his next album be checked on this system before he OKs it for release.

I'm not much impressed by internet stories and ex cathedra proclamations from self-appointed gurus with, ahem, honesty issues. I'm pretty data-driven.

[jkeny]

Originally Posted by SY

Well, first, I don't have any equipment from Benchmark. Mistyping on one of our parts?

yes, my typo - tiredness from a very disturbed night's sleep!

Second, both of the DACs I actually use measure better than -115dB to the noise floor and THDs below 0.002%. They sound excellent when the gain structure is set competently. One local musician (who is uncharacteristically interested in sound and sound technology) was so delighted with the sound, he's insisting that the mastering of his next album be checked on this system before he OKs it for release.

OK you've got measurements but don't expect us to believe anecdotal stories of subjective impressions as evidence

I'm not much impressed by internet stories and ex cathedra proclamations from self-appointed gurus with, ahem, honesty issues. I'm pretty data-driven.

Well you might be interested in Gary Pimm's analysis of the Behringer DXC2496 http://www.pimmlabs.com/web/behringer.htm - pretty much slates the analogue section & says get rid of it

[Joseph K]

Hm. In the TIE trend signal there is also an ~4KHz (250usec) component.
I can not read the settings in the picture, is it something around there?
Though this 4khz is a saw signal, this last scope shot is triangular..

[jkeny]

Originally Posted by Joseph K

Hm. In the TIE trend signal there is also an ~4KHz (250usec) component.
I can not read the settings in the picture, is it something around there?
Though this 4khz is a saw signal, this last scope shot is triangular..

I would have to look back at my notes if I can find them or repeat the measurement

[SY]

John, most of Gary's analysis deals with the analog input section, which is not used here.

And yes, I would not submit my anecdote as any sort of rigorous evidence!

[jkeny]

Originally Posted by SY

John, most of Gary's analysis deals with the analog input section, which is not used here.

And yes, I would not submit my anecdote as any sort of rigorous evidence!

No, it says get rid of the analogue output section:

The output circuits of the DCX2496 are just more of the same low grade circuit designs like the input:

Just say no to the output circuits.

The weak link is the analog input and output circuitry

What do you think of the ASRC ?

[woodturner-fran]

Great set of informative, logical posts over the last few pages after so much noise earlier.

Please continue!

[jkeny]

Agreed, Fran ,let's please continue but without the ad-hominem attacks

[SY]

Originally Posted by jkeny

What do you think of the ASRC ?

Unfamiliar with it.

I'll probably change over the analog output to the passive circuit published by Jan Didden as soon as I have a few weeks at home. With well-established levels, restricted bandwidth, and a healthy voltage level, I seriously doubt that the output section is the limiting factor; that's why 3/4 of Gary's page concentrates (rightly, IMO) on the input section where this is not the case.

edit: If you're talking about the DCX input receiver (not the case for my other DAC), I have had problems at spdif levels, but far fewer with higher voltages. It's never done the "dull sound" thing, and I've only had it go frying eggs once. The high output of the Hiface is an advantage here.