[Ori]

Quote:

Originally Posted by HumanMedia What is the reason for recommending to ground the chassis in the DAC 1.3? and generally?

The chassis of the 1.3 is floating. It is not connected to the circuit ground. In general, it is a good idea to ground (to AC ground) any large metal surface around your circuit, because then it behaves as a shield from RF energy. Floating chassis may behave like an antenna, picking up RF noise and coupling it capacitively to your circuit.
I would not ground the chassis to the circuit ground only. By doing that you are adding noise. If a circuit is not stable and has a tendency for oscillations, then connecting a large capacitor (i.e. the chassis) "tunes" it in a way the reduces this tendency. That technique is a "band-aid", not a fix to the basic problem.
In practice, I found the 1.3 very good in regard to noise pickup, so grounding the chassis is a precautionary measure only.
Quote:

Should the ground on the output from the rcas be attached to the ground of the source and target devices?

The RCA ground actually connects to the circuit ground of the source and target devices through the digital cable and the interconnects. It makes no sense to run a separate ground wire for circuit grounds.
The chassis, on the other hand, may be grounded in a "star" approach with the chassis of the other components in your system, and then grounded to the AC "earth" at one point only. This requires that all chassis are floating, i.e. none of them is connected to a circuit ground.
All these measures are intended to eliminate noise. If you don't have a noise problem then don't "fix" anything.

 

[TigzStudio]

Hey,

Anyone running 3 of the DY2000 on the main dac boarD? in v 1.3 Zhalou?

Could you give some impressions?

 

[zdogg]

Quote:

Originally Posted by TigzStudio Hey, Anyone running 3 of the DY2000 on the main dac boarD? in v 1.3 Zhalou? Could you give some impressions?

I have some on the way, will post my impressions when they get here (for both 1.3 and 2.0).

 

[yo2tup2]

so i have a dy2000 in the center, i just biased the side AD823's to class A...

....holy crap...that's what i'm talkin about...

 

[HumanMedia]

Quote:

Originally Posted by TigzStudio Hey, Anyone running 3 of the DY2000 on the main dac boarD? in v 1.3 Zhalou? Could you give some impressions?

I am and I love it. Its my favorite opamp configuration. It takes the DAC 1.3 signature and embellishes it. The very top end isnt perfect, but every other aspect is great - nice deep bass, spacious midrange.

In fact I dont know if I would characterize the Zhaolu as being particularly 'accurate' in HiFi terms, but it generates a space (especially with 3 x DY2000) that sounds great and immersive and works with all material.

 

[HumanMedia]

DAC 1.3 Resonance Isolation/Coupling.

Ive been trying some different isolation methods to see if it made an audible difference. Ive tried it with other components before and it hasn't made a major difference, but with the Zhaolu its quite noticeable.

It seems that using the standard foam feet under the chassis, gave a midrange emphasis. Then I tried using two types of rubber feet, from harder to softer, some Herbies feet, and some QuietFeet (made for home theatre PC's). It seems that feet of the unit, the lower this tonal emphasis moves. Why there is a correlation between the vibration frequency of the physical circuitry and the audible frequency that circuit produces, I dont know. But it is noticeable and can be used to advantage.

If you want a nice across the bass emphasis the Herbies work well. For my system that wasnt really ideal, and I preferred the QuietFeet which moved the bass down further. The QuietFeet seem to be some silicon-like compound.

(BTW I am on sprung wood flooring which introduces a lot of vibration, and find that for my components that isolation works better for me than coupling, with spikes etc)

 

[HumanMedia]

Quote:

Originally Posted by Ori The chassis of the 1.3 is floating. It is not connected to the circuit ground. In general, it is a good idea to ground (to AC ground) any large metal surface around your circuit, because then it behaves as a shield from RF energy. Floating chassis may behave like an antenna, picking up RF noise and coupling it capacitively to your circuit. I would not ground the chassis to the circuit ground only. By doing that you are adding noise. If a circuit is not stable and has a tendency for oscillations, then connecting a large capacitor (i.e. the chassis) "tunes" it in a way the reduces this tendency. That technique is a "band-aid", not a fix to the basic problem. In practice, I found the 1.3 very good in regard to noise pickup, so grounding the chassis is a precautionary measure only. The RCA ground actually connects to the circuit ground of the source and target devices through the digital cable and the interconnects. It makes no sense to run a separate ground wire for circuit grounds. The chassis, on the other hand, may be grounded in a "star" approach with the chassis of the other components in your system, and then grounded to the AC "earth" at one point only. This requires that all chassis are floating, i.e. none of them is connected to a circuit ground. All these measures are intended to eliminate noise. If you don't have a noise problem then don't "fix" anything.

Many thanks. And would the Preamp usually be the grounded center of the 'star'?

 

[Ori]

Quote:

Originally Posted by HumanMedia Many thanks. And would the Preamp usually be the grounded center of the 'star'?

That is a natural "center" in any system. Again, you must make sure that you're not bypassing signal grounds, if they are connected to the two chassis on both ends of any interconnect in your setup.
Use a thick copper braid for the ground straps. I've seen several phono cables with an extremely thin ground wire, which is less than optimal for the task...
Quote:

Why there is a correlation between the vibration frequency of the physical circuitry and the audible frequency that circuit produces, I dont know

Many components are microphonic, especially capacitors. Since the chassis itself is not stiff, you might want to add a "brace" from top to bottom in the middle. A stand-off or a long screw will do the job.

 

[eVITAERC]

Quote:

Originally Posted by yo2tup2 so i have a dy2000 in the center, i just biased the side AD823's to class A... ....holy crap...that's what i'm talkin about...

How much did you bias it by and how did you do it?

 

[Ori]

Quote:

Originally Posted by yo2tup2 i just biased the side AD823's to class A...

Hopefully with a high-impedance current source. This is a low-pass circuit and a change of impedance would affect the original frequency response.

 

[udo]

I have some 2604's, DY2000, 627 (dual on small PCB) besides the LT opamps the D2.0 comes with.
What is the right opamp combo to start with if I know the sound of a modded 1.3? I know the ultimate decision can be made by listening, but because of burn in time etc I would like some suggestions.
Opinions? Suggestions?

 

[skysaxon]

I've done only a few mods - disconnecting headphone and cutting off the caps, but BY FAR the biggest mod isn't even a mod, it's going back to the original - switch the opamps to the three 2604's. My god, babies your 2.0 will sing.

 

[device manager]

Quote:

Originally Posted by skysaxon I've done only a few mods - disconnecting headphone and cutting off the caps, but BY FAR the biggest mod isn't even a mod, it's going back to the original - switch the opamps to the three 2604's. My god, babies your 2.0 will sing.

I agree. After playing with different configs last week I replaced the two LT1057's w/ 2604's for the headamp and the DY2000 remained in place for the DA. A couple of days later I decided to replace the DY2000 with a 2604, and then I replaced the TI TL082CP on the upgraded (discrete) headamp with a 2604 as well. The mid-bass seems to have better depth and it tamed the highs, which is a good thing since I have the K701.

 

[skysaxon]

Quote:

Originally Posted by device manager I agree. After playing with different configs last week I replaced the two LT1057's w/ 2604's for the headamp and the DY2000 remained in place for the DA. A couple of days later I decided to replace the DY2000 with a 2604, and then I replaced the TI TL082CP on the upgraded (discrete) headamp with a 2604 as well. The mid-bass seems to have better depth and it tamed the highs, which is a good thing since I have the K701.

Yeah, let the truth out, device manager. Everyting sounds better. The most obvious, and for many people, the only mod you'll need. (The caps cutting and headphone disconnecting negligable results at most).

Now, my next audio goal is to get a pair of 701's, I hear they are fantabulous. My 580's are cool but I hear that the 701's are so good, you'll wanna cry! And maybe the key that will enable me to fully be able to hear the subtle difference between cap obliviations.

 

[Sinwerm]

Quote:

Originally Posted by device manager I agree. After playing with different configs last week I replaced the two LT1057's w/ 2604's for the headamp and the DY2000 remained in place for the DA. A couple of days later I decided to replace the DY2000 with a 2604, and then I replaced the TI TL082CP on the upgraded (discrete) headamp with a 2604 as well. The mid-bass seems to have better depth and it tamed the highs, which is a good thing since I have the K701.

Do you think this config will change for you when you get the Headfive ? will the amp have an effect on the DAC ? (I imagine the sound should change). Im just following this closely since we will be haveing a similar set-up (identical almost) and looking for a baseline to start with before I swap things. Also Eddie is going to upgrade to the reddish elna caps for me as he calls them , not sure of the part number any info on them ? Thanks. Great thread here btw.