transformer attenuator directly from v-out dac - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, 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 22nd March 2011, 03:06 AM   #1
diyAudio Member
 
Join Date: Feb 2008
Default transformer attenuator directly from v-out dac

Hey guys,

so. I've read into transformer output from balanced v-out dacs (e.g. wolfson wm8740). I always thought 'screw that' I'll just use a cheap coulpling cap. A waste of a balanced output and impedance but I don;t need both of those aspects when i connect it to a simple pot meter.

But then. I came across some transformer volume control.

I'm thinking about the following setup:

wm8740 -> sowter 9335 (direct coupled, no caps or anything, so there will be dc on the transformers)

SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL


So...
1. Is this possible? can the sowters handle the dc from the wm8740?
2. has anyone experience with such a setup? does it makes sense?

Thank you
  Reply With Quote
Old 22nd March 2011, 12:43 PM   #2
RIP
 
Join Date: Oct 2005
Location: Central Florida
It makes sense to me, although I've never used a TVC. Unless the WM8740 needs an inordinately high load resistance it should work great.

The DC offset is a non issue. If there is no path to ground there is no DC current flow unless the output pins have differing DC potentials.

Best, Bill
  Reply With Quote
Old 5th January 2012, 01:07 PM   #3
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
What are you putting on the secondary side of the TVC? Be aware that any impedance there will be reflected back to the DAC, and that may effect the DAC's performance and output level. Also, the impedance reflected onto the primary side will change with changes in volume, since the secondary is tapped and thus the turns ratio effectively changes as well.
  Reply With Quote
Old 5th January 2012, 02:45 PM   #4
Account disabled at member's request
 
Join Date: Apr 2009
Check datasheets guys, it's all in there.
Should work well; DC offset is 2.5V with a 5V supply.
In Sowter's application no path to ground (floating).
When secondary load impedance is 10k or higher it will work well.
Dirk, when the signal is attenuated the dac will see a higher (reflected) load, so it will actually have an easier job (output level for this voltage output dac will not be effected).
  Reply With Quote
Old 5th January 2012, 07:46 PM   #5
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Quote:
Originally Posted by pieter t View Post
Check datasheets guys, it's all in there.
Should work well; DC offset is 2.5V with a 5V supply.
In Sowter's application no path to ground (floating).
When secondary load impedance is 10k or higher it will work well.
Dirk, when the signal is attenuated the dac will see a higher (reflected) load, so it will actually have an easier job (output level for this voltage output dac will not be effected).
I didn't read the data sheets, sorry, but I was just talking in general.
  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
Connecting a MF tube buffer directly to AKM DAC ronenash Tubes / Valves 7 13th December 2010 10:44 AM
DAC that will drive headphones directly jkeny Digital Line Level 7 27th January 2010 11:00 AM
passive I/V directly into transformer ? Bernhard Digital Source 6 17th August 2005 08:39 PM
DAC directly drives headphones & speakers ? Bernhard Digital Source 21 13th January 2005 05:02 PM
16 x TDA1543 DAC directly drives headphones Intermod Digital Source 3 7th September 2004 10:09 PM


New To Site? Need Help?

All times are GMT. The time now is 02:52 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