Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 26th February 2004, 12:50 AM   #1
Thunau is offline Thunau  United States
diyAudio Member
 
Thunau's Avatar
 
Join Date: Mar 2001
Location: PA USA
Default Next logical step in that quest for symetry?

While gathering parts for the AX and looking at different transformers I thought why not balance the AC before it hits the power supply? I used to run on balanced power in my recording studio and the gear sounded great on it. So I asked a friend of mine who originally hooked me up with the balanced iso transformer if he had another one (I left the old one installed at the studio when I closed down and moved out). He said yes, so after a quick trade for some speaker cabinets I ended up with this 75lb. 5000VA monster in my office.
Click the image to open in full size.

It measures dead on +61V/-61V to within 0.01V most of the time. Hard to say how close the windings are because the voltage fluctuates a bit, but it reduced what little hum I had in the system by at least a few dB to almost non existent. I have to put my ear right to the woofer to hear it.
I would think it makes sense to power the A-X from it. Doesn't it?
__________________
"Most people just say what they know, the wise ones know just what to say."
  Reply With Quote
Old 26th February 2004, 03:02 AM   #2
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
There are other potential issues, such as increased isolation from RF, DC, and digital artifacts in your AC line.
All to the good, of course.
I picked up a few isolation toroids from one of the surplus houses a couple of years ago and have been very pleased with the result, especially since they were quite cheap. I added some odds and ends from my junk box and ended up with power supply boxes for nearly nothing.

Grey

EDIT: It's been my experience that it makes more difference in the low level stuff like preamps and crossovers, than later in the chain. But that's not to say that you shouldn't pursue it for an amp.
  Reply With Quote
Old 26th February 2004, 06:41 PM   #3
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
I have some nice monster isolation transformers 120 to 120
which have an electrostatic shield between the primary and
secondary, and I find that properly grounded, the shield makes
a real difference. We use them here, driven by Variacs, on our
test benches. The elimination of capacitive coupling between
primary and secondary is just as important as the additional
waveform cleaning offered by the transformer.
  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
Step-by-step guide to building a speaker Richy Multi-Way 5 5th August 2008 12:48 AM
stuffing Mileva: first timer step by step questions schro20 Full Range 7 2nd June 2008 05:49 PM
Class AB Super Symetry use Bipolar transistor Rembulan Pass Labs 9 4th October 2007 02:52 PM
how to make spherical wood horns, step by step angeloitacare Multi-Way 0 29th May 2007 01:50 AM
too logical theChris Everything Else 1 15th November 2003 02:39 AM


New To Site? Need Help?

All times are GMT. The time now is 11:42 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