Hum with aleph P - 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 13th September 2006, 05:54 PM   #1
diyAudio Member
 
Join Date: Nov 2004
Location: near bruxelles
Default Hum with aleph P

My aleph P1.7 is more or less finished and sound marvellous but I have a humm with this.

I use a attenuator boards made using relays and precision resistors in balanced mode and when I increase the volume the hum increase.

I use board from PCB design and dantimax attenuator.

I have connected 1 ground to each channel to the chassis from the main board of Aleph p1.7 and only one ground goes between the 1.7 to the board attenuator. I think that I canít have a ground loop with this configuration.

Do you have any suggestion?

Best regardís

  Reply With Quote
Old 13th September 2006, 05:57 PM   #2
diyAudio Member
 
Join Date: Nov 2004
Location: near bruxelles
picture
Attached Images
File Type: jpg img_1896b.jpg (49.9 KB, 991 views)
  Reply With Quote
Old 13th September 2006, 06:07 PM   #3
diyAudio Member
 
Join Date: Nov 2004
Location: near bruxelles
one more for the pleasure
Aleph 5 and aleph P1.7

Incredible couple.
aleph 5 4x47000uf with 500va, matched mosfet 0.001volt??? with fluke p189, all precision resistor 0.1% +matched.
All cases made by my self. I'm happy and pround but the humm is unacceptable
Attached Images
File Type: jpg img_1738 reduit.jpg (74.6 KB, 903 views)
  Reply With Quote
Old 14th September 2006, 01:38 AM   #4
diyAudio Member
 
Join Date: Jul 2004
Location: brooklyn
Send a message via MSN to tze-hao yen
ok
i had the some problem in the past too but what i find out it that if you put 4 resistor on the output will divid the nois out may be you can try it say like 4x 4.7k will work put then in the out put please try it first
  Reply With Quote
Old 15th September 2006, 08:39 AM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
why have you connected audio ground to safety earth?

Do you take orders for chassis panels?
Well done.
__________________
regards Andrew T.
  Reply With Quote
Old 15th September 2006, 06:44 PM   #6
diyAudio Member
 
Join Date: Nov 2004
Location: near bruxelles
ANDREW

I don't understand your question. Could you explain me more. What do you mean with safety earth? Where do you want I connect my ground audio?

Best regards.
  Reply With Quote
Old 15th September 2006, 07:04 PM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
mains powered equipment with exposed conductive parts must have a safety earth. This safety earth connects the conductive parts back to the electrical distribution board.

A fault current to safety earth will blow the fuse and isolate the faulty equipment from the mains Live input.

If this is new to you, then give up building mains powered equipment until you have been trained to stop killing yourself.
__________________
regards Andrew T.
  Reply With Quote
Old 15th September 2006, 08:54 PM   #8
diyAudio Member
 
Join Date: Nov 2004
Location: near bruxelles
Andrew

Sorry for my bad english but I know what is a safety earth and for proof you I can always reply to you
You have not understand my question and it's normal because sometime I speek like a spanish cow.
Meanwhile I have finded a part of the problem.
I continue but I feel that i will have maybe some help from you.
Best regards.
  Reply With Quote
Old 16th September 2006, 03:42 AM   #9
diyAudio Member
 
Join Date: Jun 2005
Location: Dallas, Texas
hmmmmmmmmmmm............
  Reply With Quote
Old 16th September 2006, 03:49 AM   #10
diyAudio Member
 
Join Date: Jun 2005
Location: Dallas, Texas
OK OK enough joking around. Lets see. You have a lot of hum and
it gets louder when the pre volume is turned up.

Do you have any hum from the power amps alone with no input
connected? It should be very quiet even when you put your ear
right by the speaker cone. Or at least you should be able to hear
nothing if your ear is a foot away from the speaker cones.

If the hum is only when preamp connected, try to disconnect all inputs
to the preamp. Do you still have hum? If not, then there is a ground
loop between the pre and the source component. If there is hum with
the pre inputs disconnected, then there is a ground problem between
the pre and the power amp.

I had a similar thing... on my power amps I had the + and G connections
reversed. Not good. I'd say look for the same sort of thing. Either the
pre output has an error or the cable has an error (are they DIY cables??)
or the power amp input has an error in the connections. THey are
all balanced connections, no?

If they are balanced, it should be so quiet it's spooky. Don't give up
til you find your problem.

One more thing - you did separate your signal ground from chassis
ground with a thermistor as in the schematics didn't you?

W.
  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
Aleph (Single Ended) + Larvadin (no Memory Distortion) = Ultimate Aleph? tiefbassuebertr Pass Labs 19 25th January 2014 02:15 AM
First version Aleph 0 (Null, ZERO, O, Os, 0s) versus later Aleph versions tiefbassuebertr Pass Labs 13 27th April 2012 02:13 AM
Mini Aleph Board & Aleph 2 Parts List gpsmithii Pass Labs 3 16th January 2010 03:58 AM
First version Aleph 0 (Null, ZERO, O, Os, 0s) versus later Aleph versions tiefbassuebertr Pass Labs 0 6th August 2009 11:11 AM
PCBs for Aleph 2, Aleph 3, Aleph 4 and Aleph 5 amplifiers kristijan-k Swap Meet 64 12th September 2002 07:55 AM


New To Site? Need Help?

All times are GMT. The time now is 08:19 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