Sound Quality Vs. Measurements - Page 131 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

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 23rd January 2012, 12:28 AM   #1301
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Mainly because the amp has low OLG but wide OL bandwith due to
use of low gain/degenerated stages , thus the amp has good OL linearity
but the feedback ratio is low and constant with frequency , hence the distorsion
being constant with frequency.

Increasing the OLG and reducing the OL bandwith of this amp would
of course reduce THD at low frequencies but it would stay the same at 10KHZ
as in the low OLG variant once the loop is closed.

Last edited by wahab; 23rd January 2012 at 12:31 AM.
  Reply With Quote
Old 23rd January 2012, 12:34 AM   #1302
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Right;

and vacuum tube stages can be wide OL bandwidth, but have good linearity increasing with lower signal amplitudes. So it can sound much cleaner on 1W average/100W peak than another amp that has better linearity on the same -3 dB from the same 100W on clipping.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 23rd January 2012, 12:44 AM   #1303
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Unlikely , as an SS amp also see increased linearity with decreasing amplitude,
and at a greater slope than tube topologies.

At low levels , SS amps are also simply out of reach...
  Reply With Quote
Old 23rd January 2012, 12:48 AM   #1304
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by wahab View Post
Unlikely , as an SS amp also see increased linearity with decreasing amplitude,
and at a greater slope than tube topologies.

At low levels , SS amps are also simply out of reach...
Again, it depends on topology of SS amps. And of tube amps, of course.

The best results I still got combining SS and tubes. Can't get such results using SS only, or tubes only.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 23rd January 2012, 01:09 AM   #1305
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Agree that a lot of ill designed SS topologies have perfs that can be
reached with tube designs but a minimaly thought SS design can not
be approached by a tube topology unless you re using a 800/1000V
slope such that you amp work only in one or two % of the curve ,
wich amount to design a MC3500 to reach perfs at a few watts that
are easily obtained by 20W SS amps......
  Reply With Quote
Old 23rd January 2012, 01:18 AM   #1306
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by wahab View Post
Agree that a lot of ill designed SS topologies have perfs that can be
reached with tube designs but a minimaly thought SS design can not
be approached by a tube topology unless you re using a 800/1000V
slope such that you amp work only in one or two % of the curve ,
wich amount to design a MC3500 to reach perfs at a few watts that
are easily obtained by 20W SS amps......
No.

You can use as deep feedback loops in tube design as in SS design, despite tubes are more linear than transistors. I still don't see why you always compare deep feedback transistor designs with no feedback tube designs. Didn't you experiment with them?

Try common emitter transistor stages with no feedback at all, then let's talk.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 23rd January 2012, 01:55 AM   #1307
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Saying no is somewhat short as an argument if it s not backed by numbers
wich invariably say the same old story for a few decades.

So far , all the tests and reviews that i have knowledge of clearly show
tubes gears as being technicaly inferior to silicon made items.

Indeed , the norm of what is good enough and what is not is not
decided by the amps designers but by the source requirements.

At the times of the LPs with about 70/75dB S/N ratio , amps with
THD at -80dB , hence below noise levels , were good enough.

Currently , with CD and its theorical 96dB S/N ratio being the reference source ,
amps must target THD at -100db , that is , an order of magnitude better
than 30 years ago.
  Reply With Quote
Old 23rd January 2012, 02:09 AM   #1308
a.wayne is offline a.wayne  United States
Sin Bin
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by john curl View Post
2.1 A, NO WAY! (with Soul--- amp)
No John for the plinus amp I had posted the graphs of before and JA commented on .....

Quote:
Originally Posted by john curl View Post
There are laws of engineering design that you can use. Please use them before making any general statemeOnt. Xover distortion will throw everything off.
Lol ..... High level global sarcasm .......P
Quote:
Originally Posted by Wavebourn View Post
Again, it depends on topology of SS amps. And of tube amps, of course.

The best results I still got combining SS and tubes. Can't get such results using SS only, or tubes only.
Look back I had asked this very question , what 1000 post ago , why no more hybrids , JC. Why no hybrid halo's ....
  Reply With Quote
Old 23rd January 2012, 02:11 AM   #1309
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Once again, please try for yourself one common emitter stage with zero feedbacks, and compare to one common cathode stage. Ten let's continue, when both of us can imagine numbers associated with them.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 23rd January 2012, 02:14 AM   #1310
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by a.wayne View Post

Look back I had asked this very question , what 1000 post ago , why no more hybrids , JC. Why no hybrid halo's ....
Why no hybrids? LAMM sells hybrids now, even Samsung does. No hybrids?

http://www.theverge.com/2012/1/3/268...um-tube-hybrid
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote

Reply


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
Quality Control differences = variations in sound quality? KT Class D 3 4th June 2014 01:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 09:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 10:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 04:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 04:02 PM


New To Site? Need Help?

All times are GMT. The time now is 04:08 AM.


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