Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Basic Questions on input to AMR DP-777 SE DAC
Basic Questions on input to AMR DP-777 SE DAC
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th May 2020, 04:28 PM   #1
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Default Basic Questions on input to AMR DP-777 SE DAC

Got a question for all you Digital folks!! I don't much dabble on this end, as it has mostly been set Digital DAC up and forget it if it sounds good (and it does).

I have an AMR DP-777 SE DAC connected to my computer (spdif off mobo).

I have the following option for DAC inputs:

Option 1: 2 x AES XLR / BNC

Option 2: 2x Toslink / COAX (RCA

Option 3 1x USB Asynchronous

All the above go thru a 6922 (or a 5670 with adapter) Tube stage after DAC and out to the preamp.

Now Option 1 is the extra special HD Digital input that goes thru another tube (6H11), and is supposed to be the recommended connection. I currently have this connected via a cable I made - BNC/COAX terminated with an RCA to computer.

Here is the issue... my computer is around 15 feet away from my DAC, and using Toslink, COAX (RCA) and BNC cable I have issues locking at rates over 48khz...cannot lock on 88khz, 96khz, and 196khz. Currently set at 48khz with no issues.

And yes, I know I could move computer CLOSER to DAC... and would rather not just purchase a $300 special magical cable to 'try"... just trying to look at the obvious things first...

Now my questions:

* I have another computer I am considering making the SOLE music source - like the one now, I get all spdif off mobo...maybe swapping computers may have stronger signal drive so I can get over 48khz to DAC?

* Async USB input may get me the higher rates (only one that does 196khz methinks), but has a cable length maximum of 5 meters - around 15 feet, correct? And the USB input does not go thru the magic 6H11 tube like inputs on option 1

* I have a sound EMU 404 sound card I can throw in my computer that may have the additional Signal drive to get that higher rate signal to the DAC...could this help?

* I am using Chrome (Pandora on hi rez) and iTunes - nothing here would matter on getting higher rates to DAC, right? Current rates set on Windows...

* Is 48khz sampling good enough? Am I kidding myself thinking computer output at higher rates would make a world of difference? I do have a couple higher rate downloaded media...

* I can get 48khz input, and upsample to 88khz or 96khz (or 196khz maybe) - theoretically, worth it and better than straight 48khz? Same input rate signal tho...never quite understood how upsampling would make a difference...

Appreciate the help!! Go easy on me, please!!
__________________
I Speak Spanish to God, Italian to Women, French to Men, and German to My Horse. Charles V
  Reply With Quote
Old 17th May 2020, 02:30 AM   #2
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Hi
Could you drop a picture of the two sides of the cable you made please ? Are they both BNC terminated ? Is there not an impedance mismatch between the plugs and the cable ?

The EMU card seems able to drive XLR/BNC.

48 khz is ok, upsampling is not so usefull if your reccordings are most 44.1 khz Red book from cd ripping.

For better result consider, something nearer, galvanic electronic isolation that exist for these speeds. And even a close renderer like a RaspberryPi for instance with a little diy work to solder a BNC plug instead a RCA on the renderer outputt hat. Cost is low, you will hear improvment and it doesn't arm to reclock before the dac whatever the dac reclock after. What you want is a clean signal with no loss and the fewest noise possible and if possible shortest ground loop. the main computer can be keeped as the library that send towards the renderer... all is about the playback software you have... then it could be a qestion for the pc section of the forum.

Now despite tube option 1, does the AMRs not known to sound better through their USB input ?

just my two cents


Edit : of course if the soundcard has XLR outputt, go for it to the AMR. 15 feets is way too much for a good result with a BNC (jitter). OK the AMR is reclocking I assume, but despite reclocking it can be heard (buffer/fifo are not 100% proof with that)

Last edited by diyiggy; 17th May 2020 at 02:51 AM.
  Reply With Quote
Old 17th May 2020, 03:36 AM   #3
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Hello,

Quote:
Could you drop a picture of the two sides of the cable you made please ? Are they both BNC terminated ? Is there not an impedance mismatch between the plugs and the cable ?
The cable I made was from a 16 foot Coax with BNC female both ends. I snipped off one BNC on on side and soldered in an RCA connection -

The manual actually advocates using a BNC - RCA adapter to use on the HD BNC connection...see attached

I had purchased a RCA - BNC Adapter, but as luck would have it (it was 2am), I ordered the wrong BNC connection, so I made my own cable...

I will look for that EMU card - I have not used it for years...
Attached Images
File Type: jpg Capture.JPG (28.7 KB, 32 views)
__________________
I Speak Spanish to God, Italian to Women, French to Men, and German to My Horse. Charles V
  Reply With Quote
Old 17th May 2020, 03:51 AM   #4
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
believe your problem comes from that. rca on the soundcard side and bnc on the Amr side. You better had use the adaptator given by AMR. 15 feets is certainly too much and if yo add the impedance mismatch it is perharps the culpritt. You should use the xlr for that 15 feets length imho and make your cable yourself with good Belden cable with the XLR correct impedance. my 2 cents
  Reply With Quote
Old 17th May 2020, 05:38 AM   #5
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
I read that SPDIF is 1v out, while AES/EBU is upwards of 9v out, and maybe why cables can go quite a bit longer without as much losses? Maybe my fix?

I have a E-MU 1212 card, not the 404 - trying to see if it has AES/EBU balanced out...
__________________
I Speak Spanish to God, Italian to Women, French to Men, and German to My Horse. Charles V

Last edited by john65b; 17th May 2020 at 05:41 AM.
  Reply With Quote

Reply


Basic Questions on input to AMR DP-777 SE DACHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Some basic questions... will852 Tubes / Valves 3 31st October 2011 07:46 AM
Basic Input Impedance Questions luvdunhill Solid State 10 20th November 2007 12:46 AM
Lm1036 Basic input questions Papageoff Chip Amps 1 4th November 2004 02:18 AM
basic questions for new guy jlh28 Everything Else 1 12th January 2004 12:49 AM
Basic Questions DarkMage Multi-Way 2 5th November 2003 02:51 PM


New To Site? Need Help?

All times are GMT. The time now is 02:42 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki