[wackyterbacky]

Quote:

Originally Posted by nopietns /img/forum/go_quote.gif Now I can confirm that the North Star Design M192 DAC locks to the I2S signal of the Esi Juli@ and the sound is quite sweet. Haven't had any problems (apart from that ESI cards don't like nVidia chipsets and have problems playing higher samplerate and bit files) Attached an image of my temporary test cable, which is the cheapest RJ45 from the nearest supermarket. I haven't spent time comparing to the sound from SPDIF signal, though. Many thanks for answers to my questions, mostly to audioengr and wackyterbacky.

Cool. Hey, I run an old NVidia GeForce video card, and I can play 24/96 wav files just fine. I can't test anything higher than 96khz because the Perpetual dac cannot lock on.

I increased the back termination resistors per Steve's suggestion and this cleaned up the signals and the sound noticeably. The DAC locks onto sample rate changes instantly rather than requiring a power cycle.

My hat's off to Steve for all his advice.

 

[stew1234]

I just ordered a juli@ and plan on using the SPDIF out for the time being. But... I'll have a DAC that can take i2s coming to me soon.

Has anyone had any experience with this (CryoParts Pop Pulse USB to SPDIF Converter) using its i2s output?

I would assume an i2s signal out of even a relatively inexpensive transport like that would sound better than the SPDIF out of the juli@? Maybe I'm wrong here but just wondering.

 

[nopietns]

wackyterbacky, it's the motherboard that has the nForce4 chipset. The same was with the ESI Maya44 card - if the signal gets higher than 24/48, the sound changes into a metallic noise and a shutdown is needed. No big deal, since 99.9% of my music is 16/44.1 from CDs.


Are these back termination resistor mods only P-3A specific or can they increase the quality of the signal for every DAC?
And I didn't quite understand how You changed the ground point for the shields. Could You please take some photos of how the the terminations on the Juli@ card look like?


If I want to test/check the quality of the I2S signal, what kind of an oscilloscope do I need and where should I measure? I could borrow one, but i need to know if they differ and if there are any that woulnd't work for these measurements.

stew1234, if You already have the Juli@, why don't You use the I2S signal from it?

 

[wackyterbacky]

Quote:

Originally Posted by nopietns /img/forum/go_quote.gif Are these back termination resistor mods only P-3A specific or can they increase the quality of the signal for every DAC? And I didn't quite understand how You changed the ground point for the shields. Could You please take some photos of how the the terminations on the Juli@ card look like? If I want to test/check the quality of the I2S signal, what kind of an oscilloscope do I need and where should I measure? I could borrow one, but i need to know if they differ and if there are any that woulnd't work for these measurements.

I am using 4 separate 50 ohm coax cables each 15 feet long. When I drove them directly from the pins on Juli@, there was awful ringing on the I2S signals, and distortion of the edges.

Steve recommended adding 30 ohm resistors in series with the I2S pins of Juli@. This isolates the outputs from the reactive load of the cable, a technique that I think is called back termination.

My new ground is the "screw hole" right next to your I2S pin header. If you look at the screw hole, there are 8 little "vias" or solder points around it. These vias are connected to digital ground ( VSS ) and I assume there is a ground plane as one layer of the PC board. So, I just flowed a little solder bump into each via. Then I used a small (1/4" maybe smaller) crimp on wire lug for my shield drain wire. I screw the lug tightly against the vias using the little screw and the threaded support.

I don't know if you need any of these mods as you are only driving a short length of twisted pair cable.

I try to post a picture later.

 

[audioengr]

Quote:

Steve recommended adding 30 ohm resistors in series with the I2S pins of Juli@. This isolates the outputs from the reactive load of the cable, a technique that I think is called back termination.

Series or Source Termination. Only series resistance at the source with no resistance at the destination. This matches the line impedance. It does not isolate anything.

This is what is going on:

The signal propagates to the destination, where it is inverted and 100% of it is reflected back to the source (because the destination is high-impedance). Then at the source, then reflection is totally absorbed because it matches the line impedance.

Steve N.
Empirical Audio

 

[Telstar]

This is the most informative thread I have found about tapping i2s out of the Juli@.
After some research I have found the only one card which has both the envy24ht-s AND wordclock input (supported in the drivers), the Infrasonic Quartet board.
Infrasonic Quartet Pro-Audio Interface

Now, because it doesnt have a modular layout like the Juli@, i would like some directions about how to grab i2s from it.

High-res pic:
linked picture

 

[Happy Camper]

Wow. Great tutorial on I2S.

 

[lag0a]

How does the Juli@ compare to the Quartet for bit perfect digital output?

 

[FallenAngel]

That might go into another thread.

"Overall" is REALLY hard to say, are you talking about the easy way of using at as an an I2S transport? The transformer-coupled coax S/PDIF, the bit-perfect output of the Envy24 PCI interface or just the balanced/unbalanced analog outputs? Lots of ways to compare; simply asking what's "overall" is better is just as impossible to answer as 'what's better - a Ferrari or Range Rover' - each has their strengths and they might just be used for different purposes.

 

[Telstar]

Quote:

Originally Posted by lag0a /img/forum/go_quote.gif How does the Juli@ compare to the Quartet for bit perfect digital output?

It should be the same, I mean, bit perfect through i2s done with two cards with the same envy chip, should be the same.

The advantage of the Quartet is the wordclock input, using which I will slave it to my DAC-to-be.

 

[studeb]

Quote:

Originally Posted by audioengr /img/forum/go_quote.gif Warning: Not all DAC's handle I2S well as far as muting. Even Northstar does it differently for the 192 versus the Extremo. If you kludge I2S into a DAC that does not have this interface, you risk loud pops and even DC at the output when the power is removed from the driving card or the I2S cable is pulled. Steve N. Empirical Audio

Hi, wish i had this thread years ago. when i kludged the I2S off the TD1541DAC in my CD player, and ran it to a P-3A. i do get some pops when the CD is on but not playing. Is there anything to be done with this?
I had assumed there was some ground issue that i had overlooked.

 

[2kw]

Hello,

I was wondering if it is possible to modify the Juli@ to use an external clock source. I have a DCX2496 that I want to replace the SPDIF receiver with the I2s signals from a Juli@. I have modded the DCX with a tentclock and figure you cant have a system running two seperate clocks. I would assume the clock signals from the tentclock would be better than the Juli@. Can the Juli@ be modified as the DCX is able to be ?? Or would I be better to just derive the clock signals from the Juli@ to run my DCX?

Anyone done this already??

Thanks.
Paul.

 

[maxzimum]

Hello all,
 
I would like to connect my Ayon DAC via i2s to the ESI Juli@ card. The connections on the Ayon are through RJ45 as under:
 
Pin 1: GND
Pin 2: BCK
Pin 3: GND
Pin 4: LRCK
Pin 5: GND
Pin 6: DATA
Pin 7: GND
Pin 8: GND
 
I would be grateful if someone could tell me the corresponding Pins on the Juli@ card. I will use CAT5 or CAT6 cable.
 
Thanks in advance,
 
Max