Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

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 9th December 2011, 05:20 AM   #18851
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Wayne,

Quote:
Originally Posted by wayne View Post
In thinking of product ratings and design one category that has done well with IC's is DACs and CD players.
I would suggest that the reason is that few people know how really design digital audio systems from scratch and how to implement circuitry that is radically different from the Datasheets.

I remember seeing several DAC's and or CDP's using Burr Brown DAC Chips and Op-Amp IV and even the GIC filters EXACTLY as per datasheet followed by extensive and expensive discrete buffer circuitry.

This is surprising when a simple common base/source I/V and LC filter instead of GIC would been by far more to the style of the company making them and would have allowed comparable specifications as well as (from where I stand) trivial implementation... Would it have sounded better? IMNSHO, abso-funking-lutly...

I've even seen Op-Amp's in Naim's top of the line CDP's and DAC's when Naim has (in theory) their own discrete stuff that would be easily usable if they only would apply themselves...

Ciao T

PS, in the 90's I wrote a little article on how to use "pure" tubes with DAC's...

http://www.fortunecity.com/rivendell...da/vasfda.html

I updated this nearly two years ago and submitted it for publication in Enjoy The Music's DIY Magazine, but Steve has so far not included this updated version for publication and I no longer operate any website suitable for publication myself.
  Reply With Quote
Old 9th December 2011, 06:14 AM   #18852
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
I was playing with similar tube line stage:
Attached Images
File Type: png lahvostroje.PNG (15.8 KB, 297 views)
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 9th December 2011, 06:35 AM   #18853
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by PMA View Post
I was playing with similar tube line stage:
The 12AU7 is one of the worst possible choices for line stages.

Try replacing it with a 5687 (or a russian 6N6 if you don't want to use western tubes) with around 500 Ohm cathode resistors...

Even better, make the upper triode's cathode resistor a J-Fet selected for the right current.

Ciao T
  Reply With Quote
Old 9th December 2011, 07:02 AM   #18854
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default 1970's Op-Amp

Guys,

As we have been spending time bashing how bad 1970's Integrated Circuits where, here is the schematic of one of these that originated in 1973.

I find it rather good...

Click the image to open in full size.

Noise will be a bit high by modern standards (around 7nV|/Hz at 1KHz and 14nV|/Hz at 100Hz) but slew rate and bandwidth of this circuit where quite good and many modern "Audio Grade" Op-Amp's are dramatically worse...

Ciao T
  Reply With Quote
Old 9th December 2011, 07:19 AM   #18855
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
I'll stick to fets, myself. Just lazy, I guess.
  Reply With Quote
Old 9th December 2011, 08:36 AM   #18856
diyAudio Member
 
Join Date: Aug 2009
Quote:
Originally Posted by john curl View Post
Tube analogue stage, Joshua? That sounds OK to me. I don't know why, but tubes do help quell digital problems ...
Because they deal / process better with high frequencyand limit consequences of hazard incidents which are left after digita-to-analogue conversion.
  Reply With Quote
Old 9th December 2011, 09:36 AM   #18857
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Folks,

Quote:
Originally Posted by ThorstenL View Post
Guys,

As we have been spending time bashing how bad 1970's Integrated Circuits where, here is the schematic of one of these that originated in 1973.

I find it rather good...

Click the image to open in full size.

Noise will be a bit high by modern standards (around 7nV|/Hz at 1KHz and 14nV|/Hz at 100Hz) but slew rate and bandwidth of this circuit where quite good and many modern "Audio Grade" Op-Amp's are dramatically worse...

Ciao T
Seems at least on my browser the schematic does not display, here as attachment instead...

Ciao T
Attached Images
File Type: png image14.png (144.8 KB, 165 views)
  Reply With Quote
Old 9th December 2011, 09:39 AM   #18858
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by john curl View Post
I'll stick to fets, myself. Just lazy, I guess.
Funny, I tend to say the exact same thing about me using tubes...

I guess it's the devil you know.

A while back I needed a circuit to Amplify and/or buffer SPDIF signals...

Naturally, my choice was to use tubes...

Ciao T
  Reply With Quote
Old 9th December 2011, 09:42 AM   #18859
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
I would rather say that they (tubes) overlap the source material by their inherent distortion pattern, which is pleasing for many listeners, but not for everyone.
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 9th December 2011, 10:46 AM   #18860
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by PMA View Post
I would rather say that they (tubes) overlap the source material by their inherent distortion pattern, which is pleasing for many listeners, but not for everyone.
That is something that has intrigued me for some time.
Just to make sure that I understand it:

Assume we have source material with a nice spray of harmonics, like from a violin or whatever. We send this through a tube stage with also a nice spray of harmonics, like a monotonous decreasing 2nd, 3rd, 4th etc.

The result, from the speaker, would have, say, 3rd harmonic from 2nd harmonic = 6th, or 3rd from 3rd = 9th, etc. In general, you generate higher order harmonics, including odds, from what's in the source.
Would this then be pleasing for some listeners?

jan
__________________
Never explain - your friends don't need it and your enemies won't believe you anyway - E. Hubbart
Check out Linear Audio Vol 7
!
  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



New To Site? Need Help?

All times are GMT. The time now is 02:58 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