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
Reply
 
Thread Tools Search this Thread
Old 21st September 2011, 04:40 PM   #261
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
That is not entirely true.

People seem to think that 2SK170 / 2SJ74 or 2SK389 / 2SJ109 are the only ones.
At the F5 thread, I have published curves for 2SK163 / 2SJ44.
They are true complementaries.

I do agree with the differences in capacitances.
But one can handle that in circuit design.


Patrick
  Reply With Quote
Old 21st September 2011, 04:47 PM   #262
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
I like BC550,560, sure. They have high Hfe and this is also very linear over a wide range of idle. They have some early effect though but that is not a problem with common base.
They have high Rbee though of around 130 Ohm. That is not a problem in most I/U converters i think. To lower that you can parallel them in a Faulkner arrangement. The 15mA you chose is also not the null in distortion. That happens when you run each transistor at about 5.5mA. So you could parallel 3 plus 3 BC550,560 each run on 5.5mA.
  Reply With Quote
Old 21st September 2011, 04:48 PM   #263
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Samoloko, when i follow your link i can not find anything like a circuit schematic.
  Reply With Quote
Old 21st September 2011, 04:52 PM   #264
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> The 15mA you chose is also not the null in distortion. That happens when you run each transistor at about 5.5mA.

I know next to nothing about BJTs.
Could you explain or link to some references ?

Or suggest another BJT for 15mA bias ?


Patrick
  Reply With Quote
Old 21st September 2011, 04:54 PM   #265
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> when i follow your link i can not find anything like a circuit schematic.

It links you to post #104 where there is a schematics in spice next to the noise simulation results.
On the left.


Patrick
  Reply With Quote
Old 21st September 2011, 05:41 PM   #266
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

Patrick, I certainly won´t put my veto in for Your circuit in #238. Anybody should feel free to evaluate this not so young circuit.
I do doubt though that it is easy practicable circuit. The double current mirrors are prone to oscillation and need very tight tolerated/matched parts. I´d rather prefer the simple structure with caps, that promises stable working and easier success.
The offset of the bipolar CEN is very low already. It might present a problem with direct coupled MC pickups but not with DACs. The voltage compliance of DACs allows app. +-1V. In BB/TI-DACs this voltage is limited to the Vf of the protection diodes. As long as the voltage swing at the CENs input remain below a couple of dozens of mV there´s no influence on the DACs THD figures.
As Joachim already told, the BCs run well on low idle currents around 5mA. current gain and saturation voltage raise above ~10mA of collector current. For higher currents the Zetex ZTX650, ZTX689, ZTX690 etc. and their complements might be interesting.

jauu
Calvin

Last edited by Calvin; 21st September 2011 at 05:49 PM.
  Reply With Quote
Old 21st September 2011, 05:45 PM   #267
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by EUVL View Post
That is not entirely true.

People seem to think that 2SK170 / 2SJ74 or 2SK389 / 2SJ109 are the only ones.
At the F5 thread, I have published curves for 2SK163 / 2SJ44.
They are true complementaries.

I do agree with the differences in capacitances.
But one can handle that in circuit design.


Patrick
What/where is the "F5 thread"?

Brad
  Reply With Quote
Old 21st September 2011, 05:57 PM   #268
heinz1 is offline heinz1  Europe
diyAudio Member
 
Join Date: Feb 2008
Quote:
Originally Posted by bcarso View Post
What/where is the "F5 thread"?

Brad
F5 power amplifier
  Reply With Quote
Old 21st September 2011, 06:19 PM   #269
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
EUVL, cancelation of distortion in BJT´s is best when they run on 2/3 Gm theoretically.
That is as far as i remember for third order intermodulation. Other bias conditions can cancel other order distortion so it is a bit complicated. BJT´s in general profit more from degeneration then Fets. When you degenerate Fets too much they develop a complex spectrum. This is different in BJts. See the PDF. This is about BJT´s.
Attached Files
File Type: pdf third_order_supp.pdf (57.0 KB, 135 views)
  Reply With Quote
Old 21st September 2011, 06:21 PM   #270
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by heinz1 View Post
Thanks! It did sound vaguely familiar, but I hadn't been around here for years until running across this thread via Google.
  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
FOR REGA Turntable>>> The heavy weight + Vta adjuster+ceramic ball prooptiki Swap Meet 1 22nd May 2010 05:57 PM
Multi-DAC: Lynx AES16 -> DIR9001/SRC4392 (-> SRC4192) -> PCM1794A novec Digital Line Level 11 11th May 2010 11:57 AM
> Audio <> music <> quick <> synergy <> angst>? rick57 Everything Else 0 4th May 2007 04:03 PM
&gt;&gt;&gt; cheap 50,000uF 60V capacitors here &gt;&gt;&gt; Lubomir Swap Meet 0 1st February 2007 03:36 PM


New To Site? Need Help?

All times are GMT. The time now is 02:41 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