Zen -> Cen -> Sen, evolution of a minimalistic IV Converter - Page 25 - 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
Reply
 
Thread Tools Search this Thread
Old 21st September 2011, 09:40 AM   #241
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
I see some good places for those cool quad-transistor heatsinks shown in the Linear Audio vol. 2 article!
  Reply With Quote
Old 21st September 2011, 10:12 AM   #242
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
I forgot to mention :

All BJTs are BC550C / BC560C matched.
Current sources are E153 matched.
If you want more drive at the output, you can parallel multiple transistors at the output stage.
Thermal coupling still crucial.
Supplies +/-12~15V.
Total consumption about 75mA as shown (single ended).
Will probably need a better heatsink than our normal Quad heatsink.

Note also phase reversal as compared with CEN / SEN.


Patrick

.

Last edited by EUVL; 21st September 2011 at 10:17 AM.
  Reply With Quote
Old 21st September 2011, 10:31 AM   #243
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by EUVL View Post
Jan,

You are absolutely right.
Pin 2 to i_in, Pin 3 to Vref, Pin 5 to Riv & Civ, done.

Small problem -- Zin = 65R.

Have to do discrete, I am afraid.
Of course you can also put 65x AD844 in parallel.


Patrick
Agreed. This is one area where your discrete solution outperforms the intergrated chip.

jan
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W. S. Maugham
Check out Linear Audio!
  Reply With Quote
Old 21st September 2011, 10:53 AM   #244
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
Quote:
Originally Posted by EUVL View Post
The ES9018 gang are never satisfied. : )





.
You forgot the requirement to do it, using only four parts, avoiding IC :-)

D.
  Reply With Quote
Old 21st September 2011, 12:56 PM   #245
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
The AD844 works but the circuit you show is simpler and better sounding i assume.
I have no objection whatsoever that a PCB gets designed. I would ad the following improvements : Input bias cancelation, better suppression of bias noise to the input transistors, a better current mirror. This is for the input stage and i build circuits like that,
that sounded excellent as an MC phono stage. I could draw a circuit if you wish. There are more elaborate versions of the diamond buffer and other alternatives but what i like with your circuit is that it shows the principles very clear in its most basic form. The main advantage is that a bipolar has about 10x Gm with the same idle current then a J-Fet so input impedance of that circuit is very low. That is good for some DA converters.
  Reply With Quote
Old 21st September 2011, 01:55 PM   #246
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Here is the input stage that i would use. Forget the AC coupling and the second stage.
R1 and P1 build a local feedback loop for trimming input DC offset. It works very stable and has to be adjusted ones the circuit is in the chain. Of cause you can use this trim also to insert a certain positive or negative DC if you wish. The input transistors are biased by fets that supply current to a current mirror. Depending on the fet you can arrange the idle at will by adjusting the source trimmers. This adjustment gives you some flexibility over the input impedance too. The value of 3.5mA was chosen for a Denon DL103 that has a resistive impedance of 40 Ohm. More idle gives you less input impedance. From the current mirror you see an RC filter supplying the input transistors.
This gives much better PSR then going from the transdiodes direct. 10.000uF is a bit extreme but it should have at least 2200uF. The sound benefits much from a big cap. The transistors chosen work extremely well in this circuit although with 30 Ohm Rbee they do not have the lowest value of base spread resistance in the business. Nevertheless the circuit is dead quiet. People that build it first thought that the circuit did not work so quiet it is.
Attached Images
File Type: gif MPP Nobrainer Servo.gif (15.9 KB, 693 views)
  Reply With Quote
Old 21st September 2011, 02:00 PM   #247
diyAudio Member
 
Join Date: Nov 2006
Location: Milan
Quote:
Originally Posted by EUVL View Post

Our current SEN / CEN protos run on an AD1865. Many of R2Rs are no longer available. Very difficult to manufacture.

.
Good article and great thread.

I have a couple of AD1862 lying around.. it seems to be a perfect fit for your SEN/CEN circuit.


Thanks
Valeriano

Last edited by Valeriano; 21st September 2011 at 02:10 PM.
  Reply With Quote
Old 21st September 2011, 02:13 PM   #248
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Here is the input stage that i would use. Forget the AC coupling and the second stage.
R1 and P1 build a local feedback loop for trimming input DC offset. It works very stable and has to be adjusted ones the circuit is in the chain. Of cause you can use this trim also to insert a certain positive or negative DC if you wish. The input transistors are biased by fets that supply current to a current mirror. Depending on the fet you can arrange the idle at will by adjusting the source trimmers. This adjustment gives you some flexibility over the input impedance too. The value of 3.5mA was chosen for a Denon DL103 that has a resistive impedance of 40 Ohm. More idle gives you less input impedance. From the current mirror you see an RC filter supplying the input transistors.
This gives much better PSR then going from the transdiodes direct. 10.000uF is a bit extreme but it should have at least 2200uF. The sound benefits much from a big cap. The transistors chosen work extremely well in this circuit although with 30 Ohm Rbee they do not have the lowest value of base spread resistance in the business. Nevertheless the circuit is dead quiet. People that build it first thought that the circuit did not work so quiet it is.
  Reply With Quote
Old 21st September 2011, 02:16 PM   #249
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Sorry, i doubled my post.
  Reply With Quote
Old 21st September 2011, 02:43 PM   #250
diyAudio Member
 
Join Date: Jun 2006
Joachim

did you used that schematic Zen -> Cen -> Sen, evolution of a minimalistic IV Converter
  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 08:11 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