Lundahl 7902 as impedance adapter for Icepower - diyAudio
Go Back   Home > Forums > Amplifiers > Class D
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

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 23rd December 2015, 08:07 AM   #1
packman is offline packman  Italy
diyAudio Member
 
Join Date: Sep 2005
Default Lundahl 7902 as impedance adapter for Icepower

Hi guys, i want to use a pair of lundahl 7902 trafos to increase input impedance on a pair of 125asx2 modules (possibly will use in BTL mode) and to reduce the voltage level (max 20Vrms from a tube pre!), the output impedance of the tube pre is 250 ohm, that pre have unbalanced output only, what wiring do you advise me to use? 2:1 can be enough or 4:1 its better? complete wiring/mod on the input of the icepower advised ?
Thanks in advance
  Reply With Quote
Old 25th December 2015, 02:55 AM   #2
packman is offline packman  Italy
diyAudio Member
 
Join Date: Sep 2005
No one have tried that combination of Icepower modules with Lundahl input trafos?
  Reply With Quote
Old 25th December 2015, 03:00 PM   #3
brik is offline brik  United States
diyAudio Member
 
Join Date: Oct 2004
Location: New York
Not really an answer to your question ,but if you don't already have the 125asx2 modules you should check out the 300ASC modules .They have a 47k ohm input impedance .Driving them with a 6sn7 beta follower preamp,no issues at all.Someone was selling them here in the Swap Meet section,also on Ebay.They have all the latest design updates and sound lovely.
  Reply With Quote
Old 25th December 2015, 03:14 PM   #4
packman is offline packman  Italy
diyAudio Member
 
Join Date: Sep 2005
Thanks Brik. Unluckily at home now i have 1 x 250asx2 and 2 x 125ASX2 and for now i dont want to spend extra money for other modules.
Anyway thanks for your post
  Reply With Quote
Old 25th December 2015, 03:45 PM   #5
Davey is offline Davey  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Bremerton, WA.
If you want to increase load resistance and reduce voltage level I would just use a resistor divider. Much simpler/cheaper than a transformer.
Unless you need the galvanic isolation.

Dave.
  Reply With Quote
Old 25th December 2015, 03:58 PM   #6
brik is offline brik  United States
diyAudio Member
 
Join Date: Oct 2004
Location: New York
Quote:
Originally Posted by packman View Post
Thanks Brik. Unluckily at home now i have 1 x 250asx2 and 2 x 125ASX2 and for now i dont want to spend extra money for other modules.
Anyway thanks for your post
If you don't have the lundahl 7902 trafos already it would cost you about the same.The 300asc's are $135.00 each on Ebay.(just checked,still there.i'm sure he'll ship to you).The lundahl 7902 trafos are listed for $150.00 each on lundahl's site.Either way good luck with your project.
  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
Help needed with Alpine 7902 + more Agent13 Car Audio 1 16th August 2015 04:32 AM
line transformer matching impedance Icepower 50ASX2 embty2002 Analog Line Level 3 3rd January 2014 04:44 PM
Which Preamp for Icepower 1000asp? (impedance) Aurality Class D 3 4th December 2010 07:12 PM
using an impedance adapter to make an external DAC drive 32Ω headphones? leeperry Headphone Systems 28 28th April 2010 12:05 AM
Wanted Lundall 7902 carolus Swap Meet 0 26th April 2009 06:15 PM


New To Site? Need Help?

All times are GMT. The time now is 10:30 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki