[d-cee]

Quote:

Originally Posted by Epicurean /img/forum/go_quote.gif It seems that my Zhaolu is very jitter sensitive or something because when I feed it from my computer through either my SBlive 24-bit or my 0404 I get a lot of static especially when the music/sound is quiet or no sound at all. Also, when it happens the Zhaolu dac boards led is blinking rapidly. This is true with both optical and coaxial connection. When I hook up my Marantz cd-player there is no problem whatsoever, both optical and coaxial, so my conclusion is that my Zhaolu is quite jitter sensitive and my computer source is very jittery/impure. And I have tried this with both the AD and the CS board and both have the same problem.

that's strange, from my 0404 it's fine, no issues at all

maybe your digital receiver is playing up?

 

[Ori]

Quote:

Originally Posted by Epicurean /img/forum/go_quote.gif It seems that my Zhaolu is very jitter sensitive or something because when I feed it from my computer through either my SBlive 24-bit or my 0404 I get a lot of static especially when the music/sound is quiet or no sound at all.

That's not jitter. The light on the DAC board shows "lock" condition. Your source is possibly not sending data when it has no data (as in mute or between tracks, like many sources) or it sends it at a rate that is significantly off from the "standard" sample rate frequencies.
The reason other systems do well in the same scenario is either due to variations between production ICs or clock sources, or that you are running under a unique software configuration on your PC. Try to compare notes with d-cee for the latter.
In the extreme case, you may have a noisy computer, which adversely affects the clock on your sound card. In the most severe case there is so much noise that data is corrupted on your card. That's not very likely.
The fact that the noise is the same on optical and coaxial means that it's not noise that's picked up on the cable.

 

[Epicurean]

Quote:

Originally Posted by Ori /img/forum/go_quote.gif That's not jitter. The light on the DAC board shows "lock" condition. Your source is possibly not sending data when it has no data (as in mute or between tracks, like many sources) or it sends it at a rate that is significantly off from the "standard" sample rate frequencies. The reason other systems do well in the same scenario is either due to variations between production ICs or clock sources, or that you are running under a unique software configuration on your PC. Try to compare notes with d-cee for the latter. In the extreme case, you may have a noisy computer, which adversely affects the clock on your sound card. In the most severe case there is so much noise that data is corrupted on your card. That's not very likely. The fact that the noise is the same on optical and coaxial means that it's not noise that's picked up on the cable.

I've tried all different software configurations(kernel streaming, asio, direct sound etc.) and bitrates(44.1,48 and 96kHz) and the only one that works from the computer is 96kHz for some reason, which means I can't use it for anything else than music that I resample in foobar. In addition, when using 96kHz there is a very faint high frequency buzz present at all times. Since this is true with both my soundcards I guess my computer is just very noisy. If that is the case, an outboard soundcard or usb->s/pdif converter might help, right? Like the pc link from Eddie or a e-mu 0404 usb.

 

[d-cee]

hi Epicurean

try these 0404 PCI config files: http://a-chau.net/0404/ - filenames pretty self explanatory

they're setup to output bit perfect to the SPDIF interfaces as well as the onboard DACs without any signal modification at all

edit: they're 44.1kHz btw, bit perfect for redbook audio

 

[Epicurean]

Quote:

Originally Posted by d-cee /img/forum/go_quote.gif hi Epicurean try these 0404 PCI config files: http://a-chau.net/0404/ - filenames pretty self explanatory they're setup to output bit perfect to the SPDIF interfaces as well as the onboard DACs without any signal modification at all edit: they're 44.1kHz btw, bit perfect for redbook audio

Well what do you know, the session works! This is just great! It only took me a year to discover this

So in the asio session only the asio out is present and all analog slides are down to zero? Why does it work better? Does the presence of the analog outs somehow screw up the digital signal or does it add physical noise? Anyway, thanks a bunch d-cee!

 

[SHLim]

Have a general question about D2.5 that hope someone here may be able to assist. I am looking for a DAC with 2 line out and wonder if the stock D2.5 has 2 genuine line out that can drive 2 different pre simultaneously. One for the sub and another for dipole speaker. Had a look at Beresford TC-7510 but it is the same line out with extra RCA.
BTW, anyone here know any other DAC with 2 line out?

 

[fran]

2.5 does not have 2 line outs. It has one line out and one pre-amp out (ie variable output).

Fran

 

[d-cee]

Quote:

Originally Posted by Epicurean /img/forum/go_quote.gif Well what do you know, the session works! This is just great! It only took me a year to discover this So in the asio session only the asio out is present and all analog slides are down to zero? Why does it work better? Does the presence of the analog outs somehow screw up the digital signal or does it add physical noise? Anyway, thanks a bunch d-cee!

well you can slide the analog volumes up and down and it won't change anything because they're all part of the DSP/mixer's functions which want to be avoided to achieve bit perfect output.

If you notice on the ASIO/Wave strip, there are SENDs straight to SPDIF and the card's analogue outs - so it all works and will always be at full volume and you can't adjust the balance either, this is because the signal isn't being remixed/processed so yeah none of the sliders etc. work

 

[SHLim]

Quote:

Originally Posted by fran /img/forum/go_quote.gif 2.5 does not have 2 line outs. It has one line out and one pre-amp out (ie variable output). Fran

I saw that D2.5 uses 2 x Op2604 for output. Is the line out and preamp out driven by seperate Opamp?

 

[d-cee]

Quote:

Originally Posted by SHLim /img/forum/go_quote.gif I saw that D2.5 uses 2 x Op2604 for output. Is the line out and preamp out driven by seperate Opamp?

they're being driven by the same set of opamps

however, the pre-amp out goes through the headphone amp as well in order to have variable volume, whereas the line-out goes straight to the RCAs

 

[jholtz]

I have a 2.5C that I've shorted the caps and rolled opamps. I like it a lot with LM4562's, but it still isn't the ultimate in the top end or midrange. I'm thinking seriously about installing a Zapfilter to get a better top end and take the mids up a notch or two. Based on the reviews, it seems that the Zapfilter will accomplish this. Please respond if I'm on the wrong track.

A few questions:

How much wire should I buy and what gauge works best?

Is the 56K resistor mod still required to eliminate hum issues?

What size RCA connectors should I get?

Thanks for the feedback!

Jim

 

[C37]

My 2.5 (ad1852) arrived Friday!. Had a bit of a fright one hour ago after doing the dc caps mod and having no sound out after reconnecting the dac.

Had forgotten to reconnect the dac board to the audio one!

Let's get a few quibbles out of the way: it won't win any Museum of Modern art design prize, a couple of things are a bit flimsy ( the volume pot is not aligned with the case, the IEC behind is so *hum* that you feel safer unplugging the whole damn cord from mains before plugging it back again ( btw, if you have not checked your mains fuse, I urge you to do so, my fuse split in two just by gently cleaning it!) etc etc...
For the rest, It works just as advertised: super, and i am really wondering how it's possible that i was missing some much information from my faithful Sony XB930 UK edition modded with LC Clock(opa2604). And all this before touching the analogue stage!

 

[Ori]

Quote:

Originally Posted by C37 /img/forum/go_quote.gif the IEC behind is so *hum* that you feel safer unplugging the whole damn cord from mains

While the soldering iron is still hot, remove the cover over the IEC plug (and the line filter) and solder the back side of the fuse housing! It might save you a lot of agony...

When you do this, check your local codes. The case is not grounded to the mains ground and you may have to do that to comply. It does have a negative impact on sound quality, since the circuit ground is connected to the case, unfortunately.
Quote:

For the rest, It works just as advertised: super, and i am really wondering how it's possible that i was missing some much information

Simple is sometimes better... Change the output jacks while you're at it. This would require de-soldering the RCA block.
Don't "finesse" it! Cut the leads on the backside, pull out the block and let it rest in peace... Then de-solder the contacts on the PCB. Before you do all that, make sure you mark which contact goes where...

 

[C37]

Quote:

Originally Posted by Ori /img/forum/go_quote.gif While the soldering iron is still hot, remove the cover over the IEC plug (and the line filter) and solder the back side of the fuse housing! It might save you a lot of agony...

Thanx for the tip, Ori.
I did not really see what you mean by "solder the back of the housing"

... I did, however, take away the plastic fuse holder and put back the fuse itself with two blobs of solder on each holding metal clip. it's a thing i already did in the genelecs in the past as there are some 8 or so fuses being shaken by the speakers.More on this later.

Earthing: After reading this:http://sound.westhost.com/earthing.htm
I will not wait to find wait what the legislation is around here...
I opened the 2.5 and took a long hard look around. Not that easy, everything is painted, you have to scrap it, and how to ensure that the whole box is grounded?Finally i settled for one of the screw holding the feet close to the iec at the back, sanded it to take the paint away and soldered it to the earth of the IEC block. AAARGh...That IEC...It almost melted down, Just by soldering ONE cable on it, about 2 seconds with a 40 W soldering iron! If you solder anything on the iec , keep the mains cable ( unplugged from the wall socket of course) in, it'll help.

Soundwise? Mamma mia...This dac reacts to the slightest mod like a puppy to a bone! Don't know which of the two as the most effect, but in my system, this as big as the caps bypass mod!
I am seriously thinking of getting a new case, decent IEC, etc. even if this involves drilling a trillion holes for the modules....i want to have some space for the zap. Also feel i will take my time now, the blackgates are'nt even burned in, i know they need a lot of time.Could'nt find any RCA in my usual shop yesterday, so that will have to wait.
BTW, any reccomandation for a decent coax SPDIF cable?

 

[cheezx]

Hello, sorry to be a nag, but this thread is just way too long to read all of. I just received my D2.5A a couple days ago, and am loving every bit of it. I've been reading about the bypassing cap mod and would appreciate it if someone showed how that is done. I've seen the picture posted above, but I'm not sure if that's the A or C version. I've soldered before, so that's not a problem. I guess I'm just asking for some simple directions.

Thanks in advance!