Zen -> Cen -> Sen, evolution of a minimalistic IV Converter - Page 24 - 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 20th September 2011, 05:04 PM   #231
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
I do not know if this helps :
file:///Users/admin/Documents/Dave%20Kimber's%20audio%20pages%20-%20TDA1543%20passive%20I:V%20resistors.webarchive
  Reply With Quote
Old 20th September 2011, 05:24 PM   #232
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Thanks for that Joachim. This was easier for me to access: http://myweb.tiscali.co.uk/g8hqp/audio/TDA1543IV.html (but that may well be my unfamiliarity with the site file system). It's probably the same reference anyway.

Note that Dave does describe the 1543 output as something much closer to a current generator in the classical sense --- a transistor collector loaded with a current source --- and remarks that it can work with a passive termination whereas other converters will tend to have excessive distortion.

Brad
  Reply With Quote
Old 20th September 2011, 05:32 PM   #233
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
PCM1704 or newer chips?

Patrick
  Reply With Quote
Old 20th September 2011, 05:36 PM   #234
diyAudio Member
 
Join Date: Jun 2006
would anyone post a link to a balanced pcm1704 dac schematic
  Reply With Quote
Old 20th September 2011, 05:36 PM   #235
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
EUVL, do i see Fets in there modulated by a BJT current source ?
  Reply With Quote
Old 20th September 2011, 05:43 PM   #236
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Looks to me as if the FETs are merely steering straightforward constant currents from the bipolars into or away from the R-2R network. To the extent that the output Z's of the bipolars are sufficiently high, relative to the R's of the network, the output current pin should have a relatively constant impedance with code changes.

Brad
  Reply With Quote
Old 20th September 2011, 09:07 PM   #237
smyslow is offline smyslow  Europe
diyAudio Member
 
Join Date: Feb 2009
Location: Villach
Wonderful minimalistic design, Patrick! It seems that you never sleep.

Just ordered LA, vol. 2. Can't wait to read your full article and build a SEN (of course after I've finished the F5X )

Uwe
  Reply With Quote
Old 21st September 2011, 08:41 AM   #238
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
The ES9018 gang are never satisfied. : )


What do they want (not much) :

1) Ground referenced split rails
2) Built-in Vref circuit
3) No cap in signal path (not even in current mode)
4) Same circuit for 2 to 8 channels
5) Input impedance < 1R
6) Output impedance < 100R

Do I have a design for that ?
You bet.


The usual disclaimer :

a) I have not built, so build at own risk.
b) I have not even simulated, so no idea of performance.
c) The circuit incorporates ideas from Calvin & Joachim, so no PCB from us unless they explicitly agree.


Critical note :

1) Thermal coupling of transistors within each red box is absolutely essential.
2) I would at least make sure they are all hfe matched to much better than 5%.


I do hope someone will build this or something similar and compare to a SEN / CEN.
And please let us know whether the complexity results in better performances sonically.




Patrick

.
Attached Files
File Type: pdf CEN BJT CM Sch V1.pdf (39.7 KB, 438 views)
  Reply With Quote
Old 21st September 2011, 08:48 AM   #239
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
[snipWhat do they want (not much) :
[snip]Patrick

.
It's a crippled AD844 !
But the design looks nice, Patrick.

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, 08:56 AM   #240
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
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
  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 09:06 PM.


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