Audio-Gd Master 7 - Discrete Fully Balanced DAC (PCM1704)
Oct 18, 2013 at 12:09 PM Post #886 of 4,463
Do you have any jitter specifications on these things? I would go by these if you can't demo them yourself. Or if there's a money back guarantee within 30 days you could buy the two you fancy most and compare them at home - and then keep the one you prefer most.
 
Oct 18, 2013 at 4:38 PM Post #888 of 4,463
Group buy of the Off-Ramp? +1 depending on the final price, I am not sure yet.
 
Oct 18, 2013 at 5:01 PM Post #889 of 4,463
Well, once I get my Sr-009s in, I am going to be borrowing one first to see how much better it is than the built in USB32 in the M7, but from everything I've read it blows it out of the water, I just want to hear it for myself. Then I'll be picking it up.
 
Oct 18, 2013 at 6:06 PM Post #890 of 4,463
I just ordered one all options , he is marketing a PSU as well not selling as yet. It better be fantastic, it is about what the M7 cost but I can use it with other dacs. Does anyone here have there dac ..?? Black for sale ??
 
Oct 19, 2013 at 6:14 PM Post #893 of 4,463
Yes that's the one. The psu is not ordered yet it is not listed on the website yet.
But Steve emailed me and said he does shows with that and a short block.
 
Oct 23, 2013 at 5:59 AM Post #894 of 4,463
Hi again guys,
 
I have been looking arround and I would like to share my idea and see what do you think if you want. CIAudio has a very good interface Transient MKII and its XMOS USB interface fits in my system. Its SPDIF could easely connected to the M7 but I want to use the I2S DAC input. I have contacted different cable suppliers to find a customized cable from minidin 5p to RJ45 connectors. Some of them agree to build the cable but good performance cannot be assured. Revelation Audio Labs offers a completely build and customized cable arround 400$.
 
My doubt arround this are:  Is it intrinsically worse than a regular (not customized) cable (equal termination)??. Can we have impedances issues or may be could we add more jitter than what we pretend to avoid?? Is it worth it? Would it be better to use another Digital Interface that do not require such customization? or same SQ can be achieved??
 
I would appreciate your comments.
 
Thank a lot
JM
 
Oct 25, 2013 at 10:21 AM Post #895 of 4,463
My doubt arround this are:  Is it intrinsically worse than a regular (not customized) cable (equal termination)??. Can we have impedances issues or may be could we add more jitter than what we pretend to avoid?? Is it worth it? Would it be better to use another Digital Interface that do not require such customization? or same SQ can be achieved??

I am currently auditioning an Off Ramp 5 and I scratched my head over what I2S cable to use with the Master 7.  My cable, until I can find something better, is a short piece based upon CAT 5 that cost me about one dollar.  Using the cable I don't hear any bit errors in the audio but I'm sure it is not optimal.   But what cable type is speced for the I2S interface which has no industry standard at present?   Luckily the Off Ramp 5 is designed for 130 ohm impedance and Kingwa told me the Master 7 is terminated at 130 ohm.  That is a good start.
 
I don't know why 130 ohm was chosen.  I can't find any 130 ohm coax cable.  CAT 5 driven differentially has a characteristic impedance of 100 ohms but the RJ-45 I2S interface uses single ended TTL signaling so in my case the CAT 5 cable impedance is about half (50 ohms).  Plus the Master 7 uses a short piece of ribbon cable inside to couple the internal RJ-45 signals to the Master 7 circuit board and has its own characteristic impedance.   Connectors, headers, circuit boards have their own impedances.  So I wonder what a $500 dollar I2S cable is really going to buy me in performance as it may be swamped by other components on the I2S signal's journey to the Master 7.   And, of course, the goal is to match impedances for maximum energy transfer and no reflected signals that can mess with the signal edges and introduce jitter.  So still searching for the best and affordable cable.
 
Oct 25, 2013 at 10:55 AM Post #896 of 4,463
Hi DACLadder!!
 
Very interesting!. When you talk about 130Ohms impadence you mean at RJ45 right?? I get confused when you say "130 Ohm Coax cable". SPDIF coax is 75 ohms as you already know.
 
The cable of RAL that I am talking about was designed for Empirical Audio, in fact, you can buy the standard through their web. May be is exactly what you need. The path between the DI and the DAC is much longer than internal so I think it should be a better cable. My opinion is that during the journey to the DAC through those connections that you refer you should only care that impedances match for power transmition. I imagine that internal conections in M7 have been carefully designed and I don´t have to worry about this.
The only problem, quite expansive....
 
Take care,
JM
 
Oct 25, 2013 at 1:54 PM Post #898 of 4,463
I have an off ramp coming in a few days with the cable for about 400 or so. I honestly do not know what cAble he is sending me . I would guess it is cat 6 shielded . But that is a guess . I have a denon I link cable it's i2s as well and it is what I said above , and the pin termination is not a standard a or b data standard pin out. As for the sound being better who knows but getting the off ramp with all the options I just had to have his cable...

AL D
 
Oct 26, 2013 at 11:31 AM Post #899 of 4,463
 When you talk about 130Ohms impadence you mean at RJ45 right?? I get confused when you say "130 Ohm Coax cable". SPDIF coax is 75 ohms as you already know.

Yes, I use the RJ45 which is a 130 ohm interface.   The HDMI I2S interface I assume is based upon differential LVDS chips and is usually a 100 ohm system.   Researching yesterday for 130 ohm cables I find that some ribbons cables, like used on old IDE drives, when driven differentially are around 130 ohms but lower single ended.   My first choice for a single ended cable where I want to preserve wave shape from point A to B is to use coax of some type hence my comment I can't find 130 ohm coax.   For that matter I can't find any single ended cable type or variety with 130 ohm characteristic impedance.  The rule of thumb is if you mismatch a cable impedance keep it as short as possible.  In my case with the 1 dollar CAT 5 I2S cable it is only 6" long to keep the affects minimal.
Don't forget to post impressions!  I am interested in how you think the Audiophileo compares with the Off Ramp.

I've been holding off on comments until the OR5 breaks in some.  The OR5 is turbo clocked and Hynes regs on the I2S interface.  I've only had it for 5 days but first here is what I don't like.   Bass is a little attenuated and highs seem exaggerated slightly compared to the AP1 + PP through Input #1.  It sounds somewhat like the Master 7 did initially so won't judge until it breaks in some more.  After about 30 minutes warm up though things improve dramatically.  I do hear less sibilance and imaging is like a rock.  There seems to be much more precision to the audio signal but bordering on clinical and etched at this very early point.   But I hear many good things.  It passes the Sheryl Crow, Madonna, Phil Collins vocal test.   But I have to wait maybe 200 hrs break in for complete nirvana.   So looking for more bass and a little warmer sound.  The AP1 + PP on Input #1 is really a good sound - big, warm, and comforting.  If I could get a little of that with the OR5 I would be very happy.  And all this goodness with a 1 dollar I2S cable which may be the big issue until something else it tried.  So we'll see in time but very encouraged by the OR5 thus far.
I have an off ramp coming in a few days with the cable for about 400 or so. I honestly do not know what cable he is sending me . I would guess it is cat 6 shielded . But that is a guess

Please come back an post your experience with the OR5 and the uber I2S cable.  If you can describe the cable or supply a close-up picture would be appreciated.  If it is a Revelation cable it is supposed to be silver wire but how is that cable constructed is my nagging question.
 

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