PASS ALEPH 5 -"WOBBLY OFFSET" - diyAudio
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 21st March 2013, 11:07 AM   #1
diyAudio Member
 
Join Date: May 2002
Location: oz
Default PASS ALEPH 5 -"WOBBLY OFFSET"

Hi All

I've been running a diy Pass A5 for a couple of years now, (with great joy)

Recently I completed my home made ribbon speakers and had connected them to the A5 via a 4 ohm resistor in series with the ribbon rather than use a matching transformer.
The ribbon is 26" long x 1" wide and operates above 650hz with a 48dB/oct crossover via a dcx2496 crossover.

The problem is this :
the amplifier output offset is abt 40mV- which when direct coupled via the resistor causes some ribbon deflection at no signal- but not enough to be a problem....other than a wobble.... music is played and the ribbon starts to move more or less randomly -but not in time with the music .-ie: it is not a regular or constant wobble.
I would guess its frequency is random and well below 1hz and even then its not constant - deflection woves with louder transients yes - but is still more of a wobble than anything.

Is the Aleph A5 prone to a "wobbly" or varying offset???

I have resorted to using a matching transformer to avoid the problem as the ribbon will deflect outside the magnetic gap when direct coupled.


oh and the wobble is still there if the dcx2496 active is turned off....

Sound wise though....


Any comments or opinoions ?

Cheers
__________________
george a
  Reply With Quote
Old 21st March 2013, 11:33 AM   #2
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
pics
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 21st March 2013, 06:37 PM   #3
hm4nine is offline hm4nine  Europe
diyAudio Member
 
Join Date: Mar 2005
Default PASS ALEPH 5 -"WOBBLY OFFSET"

Quote:
Originally Posted by Zen Mod View Post
pics
Pics from what? I would really like to understand.....
  Reply With Quote
Old 21st March 2013, 06:47 PM   #4
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
I'm interested in physical arrangement of things in george's amp

whatever , you can put pics of Bugs Bunny , if you want ..... I would not object

__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM

Last edited by Zen Mod; 21st March 2013 at 06:52 PM.
  Reply With Quote
Old 22nd March 2013, 09:17 AM   #5
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hi,

is your A5 direct coupled or do you have an input cap?

William
__________________
een ooievaar is geen konijn want zijn oren zijn te klein!
  Reply With Quote
Old 22nd March 2013, 01:04 PM   #6
diyAudio Member
 
Join Date: May 2002
Location: oz
Hi

The A5 has an input cap

The PCB's are as per mark finnis's (actually, he made them)
__________________
george a
  Reply With Quote
Old 22nd March 2013, 09:46 PM   #7
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hi,

well then wobbly is not normal for a A5. Ive got one that is very stable once warmed up.

William
__________________
een ooievaar is geen konijn want zijn oren zijn te klein!
  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
Understanding "Voltage - Input Offset" Parameter Loren42 Analog Line Level 9 11th February 2013 04:46 PM
New Amp "ULTRASYMMETRY" from Nelson Pass - still a Concept Amplifier? tiefbassuebertr Pass Labs 23 30th October 2012 08:02 AM
Which Pass Aleph diy board for "no-cost-object" headphone amplifier? Hammerklavier Headphone Systems 43 7th August 2010 03:35 PM
Max "Safe" DC Offset morfic Solid State 13 18th August 2009 04:37 AM
PCB DESIGN "PASS" BOSOZ PCB'S ON eBAY Brad Kizer Swap Meet 12 4th January 2003 07:41 AM


New To Site? Need Help?

All times are GMT. The time now is 04:53 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