New Bryston input stage measurable distortion < 0.001% (Audio Advisor) - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

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 25th March 2016, 11:05 PM   #1
diyAudio Member
 
Join Date: May 2011
Location: Silicon Valley
Default New Bryston input stage measurable distortion < 0.001% (Audio Advisor)

Just received the Audio Advisor catalog SP116 and noticed this blurb on page 5, about the Bryston 4B cubed power amp
The new 4B3 power amplifier -- and all of Bryston's Cubed Series amplifiers -- features a new patented input circuit developed in conjunction with Dr. Alexandru Salomie that is precisely optimized and linear beyond any that Bryston has used before. ... The new input stage is so transparent its measurable distortion is less than 1/1000th of 1 percent!
So I visited the US Patent and Trademark Office website and searched for patents that either (a) had Alaxandru Salomie as one of the named inventors; or else (b) was assigned to Bryston. I only found one: US Patent number 8,466,744 (attached below).

It shows an input stage with a two complementary feedback pairs in a differential amplifier, with a current mirror load, and a third CFP used as a second stage, plus cascode. I redrew it below because the figures in the patent are crapped up with shaded overlays.

For this they got a patent?

_
Attached Images
File Type: jpg 8466744.jpg (144.6 KB, 1137 views)
Attached Files
File Type: pdf US8466744.compressed.pdf (751.3 KB, 213 views)
  Reply With Quote
Old 25th March 2016, 11:14 PM   #2
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Are sure that wasn't supposed to come out on the first of next month?
  Reply With Quote
Old 26th March 2016, 12:24 AM   #3
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by Mark Johnson View Post
For this they got a patent?
I've seen worse.
  Reply With Quote
Old 26th March 2016, 12:24 AM   #4
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
Maybe what they're patenting is how many transistors they used to achieve this result?
__________________
The Kmultiplier rail filter! -=- The Simple Kuartlotron Superbuffer!
Need something built, repaired or modded? PM me and ask what I can do!
  Reply With Quote
Old 26th March 2016, 12:31 AM   #5
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by keantoken View Post
Maybe what they're patenting is how many transistors they used to achieve this result?
The patent is worth skimming. But if one wanted to do something similar, their level of detail makes it easy to make a few changes and be unencumbered. Not that I would want to copy it anyway...
  Reply With Quote
Old 26th March 2016, 12:38 AM   #6
Banned
 
Join Date: Jan 2016
The question is whether it is true that it has the lowest distortion. How complicated is irrelevant, it's the result that matters. Just because it's simple does not mitigate the value of the idea. If it is that simple, how come he's the first one that did this. If someone actually designed and well documented about it, they can challenge the patent and get some money out of it.

If it really works, hats off to him.

I am not defending Bryston, in fact, I just bought a Nakamichi PA-7 designed by Nelson Pass. I was shopping around including Bryston and Krell. I don't care too much of Bryston reading the schematic so I decided to narrow to Threshold and Krell......but no S/300 available after waiting for 2 months, so I get the Nakamichi instead.

Last edited by StephenR; 26th March 2016 at 12:44 AM.
  Reply With Quote
Old 26th March 2016, 12:44 AM   #7
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Let's simulate the component values. I doubt the THD will be that good. The VAS stage seems to be the key, but feeding directly to an "OPS" (as is) I think there will be problems. But yes, Bryston's OPS are complex in itself.
  Reply With Quote
Old 26th March 2016, 12:47 AM   #8
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: dorchester ma
Quote:
Originally Posted by bcarso View Post
The patent is worth skimming. But if one wanted to do something similar, their level of detail makes it easy to make a few changes and be unencumbered. Not that I would want to copy it anyway...
The benefit/tradeoffs of that input stage taken in isolation are easily quantified. There are a lot more claims beyond this in the patent possibly making it so narrow that one wonders why they bothered.

BTW Fairchild disclosed a CFP input stage for an instrumentation amplifier in 1974.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."

Last edited by scott wurcer; 26th March 2016 at 12:51 AM.
  Reply With Quote
Old 26th March 2016, 12:49 AM   #9
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
Just as good can be done with less transistors, was my point. But patenting old technology, no hats off.

I will throw together a simulation.
__________________
The Kmultiplier rail filter! -=- The Simple Kuartlotron Superbuffer!
Need something built, repaired or modded? PM me and ask what I can do!
  Reply With Quote
Old 26th March 2016, 01:00 AM   #10
Banned
 
Join Date: Jan 2016
Yes, simulating it and see. Love to find out. If it works, still hats off to him. But you don't have value of R6 and R7 and the tail current.
  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
Measurable influence of speaker cable to freq response and distortion PMA Everything Else 27 11th December 2015 09:12 AM
No global feedback V TO I converter THD: < 0.001% sonnya Solid State 8 8th September 2014 05:50 PM
their customers say...Audio Advisor, be advised... adason The Lounge 2 30th November 2010 01:03 PM
CCS Loaded Input stage - reduces Distortion lineup Solid State 3 4th September 2010 04:11 PM
Amplifier do not need to have 0.001% distortion, speaker cannot reproduce quality destroyer X Solid State 39 26th November 2004 06:52 PM


New To Site? Need Help?

All times are GMT. The time now is 10:28 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki