Audio-Gd Master 7 - Discrete Fully Balanced DAC (PCM1704)
Mar 1, 2014 at 9:51 AM Post #1,427 of 4,451
Sorry to jump in here but talk about USB has me wondering about cutting +5V power on the USB cable...  Is it worthwhile even if the USB interface doesn't use it?   Which end to cut?   Seems closest to the power source would be best if it is some sort of radiated interference.  I use the Off Ramp 5 and assume the same applies to USB32.  Thanks!    
 
Mar 1, 2014 at 10:20 AM Post #1,428 of 4,451
  Sorry to jump in here but talk about USB has me wondering about cutting +5V power on the USB cable...  Is it worthwhile even if the USB interface doesn't use it?   Which end to cut?   Seems closest to the power source would be best if it is some sort of radiated interference.  I use the Off Ramp 5 and assume the same applies to USB32.  Thanks!    

Do it. I thought it noticeably opened up the soundstage with usb32. The shortblock will do the same thing, but with data filtering as well. You can also take out the ground pin. I'd recommend taping the outermost pins going into your computer with electrical tape first (pins 1 and 4) before doing anything permanent.
 
Mar 1, 2014 at 12:20 PM Post #1,429 of 4,451
  Sorry to jump in here but talk about USB has me wondering about cutting +5V power on the USB cable...  Is it worthwhile even if the USB interface doesn't use it?   Which end to cut?   Seems closest to the power source would be best if it is some sort of radiated interference.  I use the Off Ramp 5 and assume the same applies to USB32.  Thanks!    

 
The +5V cut is worthwhile. Opens up stage. You can also add common mode chokes on the data lines which is what I assume the Short Block does.
 
Mar 1, 2014 at 12:23 PM Post #1,430 of 4,451
  Oh I see, I've tried other Sabre DACs, but they're lesser ones.

 
I've tried the NFB7.32 vs M7. Have also tried other TOTL SABRE DACs. SABRE has treble issues, trust me. Especially evident if you have vinyl around or have to exposed quite a bit to it.
 
Mar 1, 2014 at 12:44 PM Post #1,431 of 4,451
   
I've tried the NFB7.32 vs M7. Have also tried other TOTL SABRE DACs. SABRE has treble issues, trust me. Especially evident if you have vinyl around or have to exposed quite a bit to it.

 
In that case so must the Ref5.32 and some expensive Naim players that I have heard because none had better treble, and many inferior, than my NFB-7.
Just saying.
 
Mar 1, 2014 at 10:05 PM Post #1,435 of 4,451
  Sorry to jump in here but talk about USB has me wondering about cutting +5V power on the USB cable...  Is it worthwhile even if the USB interface doesn't use it?   Which end to cut?   Seems closest to the power source would be best if it is some sort of radiated interference.  I use the Off Ramp 5 and assume the same applies to USB32.  Thanks!    

 
I would just tape over the pin, much more reversible that way in case you want to use the cable with a different DAC or D/D converter.
 
Mar 2, 2014 at 10:14 AM Post #1,436 of 4,451
The +5V cut is worthwhile. Opens up stage. You can also add common mode chokes on the data lines which is what I assume the Short Block does.

I would just tape over the pin, much more reversible that way in case you want to use the cable with a different DAC or D/D converter

Do it. I thought it noticeably opened up the soundstage with usb32. The shortblock will do the same thing, but with data filtering as well.

Thanks for your help.  I ordered a Short Block to try.  I work with USB and the 90 ohm common mode chokes for EMI radiation are cheap but are tiny SMD parts and need a PCB for mounting.  So rolling your own EMI filter would be difficult.  Plus don't have to cut my moderately expensive USB cables.  Taping the USB connector power pin would probably work well if you use a thin tape like regular Scotch tape.
 
Mar 2, 2014 at 11:26 AM Post #1,437 of 4,451
I tried it one time and it definitely wouldn't stay in place
frown.gif
, temperature and a posible tight fight will move the tape and maybe tap another pin
 
Mar 4, 2014 at 3:08 PM Post #1,438 of 4,451
OK, I finally ordered the Offramp 5 for my Master 7. I would like to make a CAT6 or CAT7 cable. Any recommendations for good cable and connectors? And what is the pin-layout? I saw it somewhere but found nothing...
 
Mar 4, 2014 at 4:20 PM Post #1,439 of 4,451
Congrats on the OR5 and best of luck to you on this adventure.  I sure had fun with it.  I would just use individually shielded pair CAT6 cable as CAT 7 is hard to find in bulk.  I thought the shorter the cable the better but Steve N. at Off Ramp claims there are sweet spots in the cable length which may help tune out some anomalies and signal artifacts.  Somewhere about 1.5m in length I think but could be wrong.
 
The cable pin outs are below and a straight through cable won't work.  From the Master 7 perspective the OR5 SCLK pair moves down two positions and SDATA and L/RCLK pairs move up one each.  MCLK stays the same. 
 
And since you live in Europe checkout the ViaBlue CAT 7 cable (Germany).  Silver plated and sold in cut lengths in the EU.  There a two types.  I tried the larger diameter of the two with 23 AWG wires but had a heck of a time finding RJ45 connectors that would crimp on to such large diameter wires.  Plus the thick cable had a large bending radius. So check out the smaller of the ViaBlue CAT 7 cables (EP-7 smaller, EP-7S larger).
 
Master 7 I2S RJ45 pinout is
 Pin 1 - SDATA
 Pin 2 - SDATA return
 Pin 3 - L/RCLK
 Pin 4 - L/RCLK return
 Pin 5 - SCLK
 Pin 6 - SCLK return
 Pin 7 - MCLK
 Pin 8 - MCLK return
 
Off Ramp 5 RJ45 I2S Pinout
 Pin 1 - SCLK
 Pin 2 - SCLK return
 Pin 3 - SDATA
 Pin 4 - SDATA return
 Pin 5 - L/RCLK
 Pin 6 - L/RCLK return
 Pin 7 - MCLK
 Pin 8 - MCLK return
 
Mar 4, 2014 at 4:58 PM Post #1,440 of 4,451
Thanks for the info, it will be fun! The Viablue cable seems nice. I have also found Audioquest CAT7 cables...
 
I am surprised with the length. I also thought that shorter better...
 
By the way, is the Dynamo power supply worthy? I ordered Off5+Dual turbo+Hynes regs but not sure about the Dynamo.
 

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