RF Attenuators = Jitter Reducers - Page 81 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

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
View Poll Results: Do you have a SPDIF transformer in your Digital Device
Yes 40 71.43%
No 16 28.57%
Voters: 56. You may not vote on this poll

Closed Thread
 
Thread Tools Search this Thread
Old 12th November 2010, 07:31 PM   #801
jkeny is offline jkeny  Ireland
Banned
 
Join Date: Feb 2007
Location: Dublin
Quote:
Originally Posted by SY View Post
........One of the posters (who seemed quite focused on gigahertz) pooh-poohed the Chinese unit I was using because of a slower rise time than the expensive jkeny-modified Hiface, but the system locks, data is accurately transferred to the DAC, and frankly, the square waves look a whole lot less cluttered.
No, what George said was that the Chinese unit had a slower rise time & that's why the SPDIF wave looks cleaner - faster rise time will be less forgiving of impedance discontinuities & give rise to reflections, hence the cleaner looking waveform
 
Old 12th November 2010, 07:41 PM   #802
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
You might want to re-read the stuff you just quoted, John.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
 
Old 12th November 2010, 07:46 PM   #803
jkeny is offline jkeny  Ireland
Banned
 
Join Date: Feb 2007
Location: Dublin
How about you correct me!
 
Old 12th November 2010, 08:00 PM   #804
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Start by changing "no" to "yes."
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
 
Old 12th November 2010, 08:14 PM   #805
Banned
 
Join Date: Jan 2008
Blog Entries: 2
@stormsonic

So your position is that RF attenuators produce an improvement in ANY SPDIF interface as long as the DAC doesn't fail to lose lock? That users should load their connections with as much attenuation as doesn't cause them to fall over. Or perhaps you have another suggestion as to how the exact amount of attenuation to be applied should be determined by naiive users? Oh, that'll be a listening impression, won't it?

And you're going to be the one to post a screenshot of the analog output showing an improvement in the jitter. Great. Which I presume you've been withholding up until now because you find it entertaining to watch us squabble amongst ourselves.

I notice you didn't repeat your suggestion about the 100pF capacitor. No, because if it was in series the input would appear as open circuit, and there's no good reason for having one in there in shunt.

OK, you have the floor. Put up or shut up.

w

Last edited by wakibaki; 12th November 2010 at 08:24 PM.
 
Old 12th November 2010, 08:15 PM   #806
jkeny is offline jkeny  Ireland
Banned
 
Join Date: Feb 2007
Location: Dublin
Quote:
Originally Posted by SY View Post
Yes, I'm fairly familiar with the Fourier decomposition of square waves, Gibbs and all that, but what bandwidth do you need to transmit spdif? One of the posters (who seemed quite focused on gigahertz) pooh-poohed the Chinese unit I was using because of a slower rise time than the expensive jkeny-modified Hiface, but the system locks, data is accurately transferred to the DAC, and frankly, the square waves look a whole lot less cluttered.
What he told you was why you had a reasonably reflection free SPDIF waveform from the Chinese unit - something you obviously still fail to grasp from the above quote.

Quote:
The difference is that Your cheap Chinese transmitter is having a rise time at about 6nsec. That is ~58MHz equivalent bandwith.
The hiface driver is having 1.5 nsec rise time in reality. (measured by me on 6GHz, 3,5GHz, 2GHz analog bandwith scopes)
Pardon, the most recently tested unit had less than 1nsec rise time. The older one is 1.5nsec.

At this speed (1.5nsec > ~250MHZ, 1nsec >350MHz ) your test setup has to be much more refined so as not to cause reflections. This is the difference what You see.
 
Old 12th November 2010, 08:32 PM   #807
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Originally Posted by jkeny View Post
something you obviously still fail to grasp from the above quote.
Only if you don't actually read what I wrote.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
 
Old 12th November 2010, 08:39 PM   #808
Banned
 
Join Date: Jan 2008
Blog Entries: 2
And we're back to quoting Joseph K.

The same Joseph K who didn't mind putting up a load of screenshots that he thought would convince people with no technical expertise but when asked to provide evidence of a test acceptable to you, jkeny, found it was suddenly too much trouble.

w
 
Old 12th November 2010, 08:47 PM   #809
Banned
 
Join Date: Jan 2008
Blog Entries: 2
@stormsonic

Oh, and if you think quoting that trick circuit with the amplifier makes a blind bit of difference to your case, think again. It's not typical.

w
 
Old 12th November 2010, 09:09 PM   #810
diyAudio Member
 
stormsonic's Avatar
 
Join Date: Aug 2008
@waki

will quote Joseph K again

Quote:
Originally Posted by Joseph K View Post
You are welcome, Mr. Wakibaki.
Was a pleasure to serve You well!
 

Closed Thread


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
generate jitter test signal and measurign jitter using AP2? BJAMR Digital Source 11 1st November 2010 02:07 PM
Attenuators stven Parts 0 12th January 2009 03:05 AM
Attenuators ------ Please Help soundbadger Tubes / Valves 5 13th February 2008 04:19 PM
Data Jitter Versus Electrical Jitter? 300_baud Digital Source 8 16th July 2004 07:59 PM
About Attenuators leiade Solid State 8 3rd November 2002 08:54 PM


New To Site? Need Help?

All times are GMT. The time now is 07:32 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2