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

Solid State Talk all about solid state amplification.

diyAB Amp  The "Honey Badger" build thread
diyAB Amp  The "Honey Badger" build thread
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 20th August 2014, 12:24 AM   #1171
Freecrowder is offline Freecrowder  United States
diyAudio Member
 
Join Date: Jun 2007
Great someone I can directly compare too. Did you use matched outputs? Meaning the 193 were all matched and also the 194? Did you up the bias on the VAS stage? Have you measured output? Mine is putting out 230watt single channel into 5.5ohm.
Happy so far.
  Reply With Quote
Old 20th August 2014, 12:54 AM   #1172
TonyTecson is offline TonyTecson  Philippines
diyAudio Moderator
 
TonyTecson's Avatar
 
Join Date: May 2003
Location: Maybunga, Pasig City
diyAB Amp  The "Honey Badger" build thread
Quote:
Originally Posted by Freecrowder View Post
I'm interested in knowing how hot some of you have been biasing the outputs. I mistakenly biased mine mjl21193/4 at 180-200 ma each (82mv TP1-TP2). It ran stable for hours that way in a 90 deg shop. I was playing music through it to a EPOS esl 3 and it was sounding very good. I put the other board/channel in and had it biased to 40mv(TP1-2) it was not as sweet sounding and noticebly different. Can those outputs handle that kind of bias as long as the heatsink is adaquate?
bjt's biased hard are known to have lower distortions, but then their life is also short, perhaps forced air cooling or water cooling can help keep things cool can help...try biasing them at 125mA and see how it sounds...
__________________
planet10 needs your help: Let's help Ruth and Dave...http://www.diyaudio.com/forums/plane...ml#post5010547[B
  Reply With Quote
Old 20th August 2014, 09:30 AM   #1173
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
ClassAB has an "optimum bias" current.
The output when lower than twice the "optimum bias" current is always in ClassA. It is very clean because there is NO crossover distortion.
The output when higher than twice "optimum bias" current has the least crossover distortion for that ClassAB amplifier.

If the output stage is biased to less than optimum then the output at all levels has more crossover distortion. At typical domestic listening levels the crossover distortion will be gross, because at W to 2W the % crossover distortion content is VERY HIGH !

If the output stage is biased to more than optimum, then the output at low levels stays in ClassA. The output at higher levels will have more crossover distortion than "optimum bias". Listening at normal domestic levels may result in most of the output being ClassA.
Only the transient peaks may stray into higher distortion ClassAB.
This could be quite pleasant to listen to. Especially with higher efficiency speakers and in quiet surrounds.

The next stage above that last (higher than optimum bias) is full ClassA, but the heatsinking requirement usually results in much lower maximum output. This too can sound very good and yet again this works very well with higher efficiency speakers.

The decision on whether to bias to "optimum", or higher than optimum, depends very much on the your own listening habits and your typical output currents delivered to the speakers.
__________________
regards Andrew T.

Last edited by AndrewT; 20th August 2014 at 09:34 AM.
  Reply With Quote
Old 20th August 2014, 09:36 AM   #1174
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
bjt's biased hard are known to have lower distortions,
This statement is misleading.
It omits the limited conditions for which it holds true.
In general the limiting conditions are not met and the opposite is the case.

BJTs biased hard are known to have higher crossover distortions, than an optimally biased ClassAB, when the output current exceeds twice the bias current.
__________________
regards Andrew T.
  Reply With Quote
Old 20th August 2014, 10:39 AM   #1175
TonyTecson is offline TonyTecson  Philippines
diyAudio Moderator
 
TonyTecson's Avatar
 
Join Date: May 2003
Location: Maybunga, Pasig City
diyAB Amp  The "Honey Badger" build thread
AndrewT, in the case of the honeybadger, what is the optimum bias?, give us a number we can work on...

Quote:
BJTs biased hard are known to have higher crossover distortions
my experience tell me this is not true....i have had amps that had heatsinks very painfully hot to touch and yet sounding so good...
maybe your experience is different, no?
__________________
planet10 needs your help: Let's help Ruth and Dave...http://www.diyaudio.com/forums/plane...ml#post5010547[B
  Reply With Quote
Old 20th August 2014, 10:58 AM   #1176
jdg123 is offline jdg123  United States
diyAudio Member
 
jdg123's Avatar
 
Join Date: Jan 2010
Location: Traverse City, Michigan
diyAB Amp  The "Honey Badger" build thread
Freecrowder, I "diode matched" my 193s and 194 outputs. I have not altered the VAS.

I have not actually run the bias up...yet. I have huge heat sinks. I am waiting to hear from others any cautions I should hear before I risk loosing my Honey Badger; it is a pretty sweet amp!
  Reply With Quote
Old 20th August 2014, 11:03 AM   #1177
TonyTecson is offline TonyTecson  Philippines
diyAudio Moderator
 
TonyTecson's Avatar
 
Join Date: May 2003
Location: Maybunga, Pasig City
diyAB Amp  The "Honey Badger" build thread
if you read up and follow Ostrippers' build recomendations you should have no problem,
i did and my badger worked the first time, you can too...
__________________
planet10 needs your help: Let's help Ruth and Dave...http://www.diyaudio.com/forums/plane...ml#post5010547[B
  Reply With Quote
Old 20th August 2014, 12:39 PM   #1178
Freecrowder is offline Freecrowder  United States
diyAudio Member
 
Join Date: Jun 2007
Ok after testing boards seperately for a couple of days just now testing with both running. Problem, one board has higher gain than the other probably 6-8 dB. Hopefully just a resistor misplaced. I did not match any transistors could that be the problem. Offsets look good and biases ok.
  Reply With Quote
Old 20th August 2014, 04:26 PM   #1179
jdg123 is offline jdg123  United States
diyAudio Member
 
jdg123's Avatar
 
Join Date: Jan 2010
Location: Traverse City, Michigan
diyAB Amp  The "Honey Badger" build thread
I built to spec, no issues at all :-).

I'm just wondering if more bias, keeping it in class A longer, will make it even better ?
  Reply With Quote
Old 20th August 2014, 06:26 PM   #1180
Freecrowder is offline Freecrowder  United States
diyAudio Member
 
Join Date: Jun 2007
Well the amp I have been listening to for many years now is a Class A design. I think it sounds very good. So the longer it is in A as long as the heatsinking is up to the task I think it would sound better.
  Reply With Quote

Reply


diyAB Amp  The "Honey Badger" build threadHide 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
diyAB Amp - The "Honey Badger" Variac Solid State 2020 20th February 2019 10:20 PM
My LM3886 build thread CanAm Man Chip Amps 22 13th July 2012 08:48 AM
Ricci's dual B&C 21SW152 build thread. Josh Ricci Subwoofers 22 12th April 2010 10:39 PM
New Project Build Thread ryoung Multi-Way 5 19th April 2008 02:15 AM
Badger Badger Badger..... Mushroom !! 5th element Everything Else 15 20th September 2003 04:16 PM


New To Site? Need Help?

All times are GMT. The time now is 02:55 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki