Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 8 of 8
  1. #1

    Member Sales Rating: (3)

    Join Date
    Aug 2004
    Posts
    285

    Question NOS tubes causing Tranny hum?

    Is it possible for "new" NOS tubes to cause transformer hum? I put a matched pair of mullard 12at7 and a matched pair of sovtek 12ax7 lps into my pre and now there is a very faint hum coming from the transformer.
    2 Channel

    Vandersteen 3a Sigs
    Music Reference RM-200
    Hovland HP-100
    VPI Scout w/ Benz Ace
    Rotel RCD-1072
    Cardas Golden Reference Speaker Cables
    Cardas Golden Reference Interconnects
    Cardas Golden Power Cords
    PS Audio UPC-200HB
    Black Diamond Racing Isolation

  2. #2
    Banned
    Member Sales Rating: (14)

    Join Date
    Apr 2005
    Location
    houston
    Posts
    2,395

    Default

    I don't know if it's possible but you could take the nos tubes out and put the previous tubes back in to see if the hum goes away.

  3. #3

    Member Sales Rating: (3)

    Join Date
    Aug 2004
    Posts
    285

    Default

    I should do that, but I'm lazy and wanted to see if anyone had some ideas. :o
    2 Channel

    Vandersteen 3a Sigs
    Music Reference RM-200
    Hovland HP-100
    VPI Scout w/ Benz Ace
    Rotel RCD-1072
    Cardas Golden Reference Speaker Cables
    Cardas Golden Reference Interconnects
    Cardas Golden Power Cords
    PS Audio UPC-200HB
    Black Diamond Racing Isolation

  4. #4

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,265

    Default

    Bad tube(s) cause all kinds of noise issues. Swap the known good tubes back in one at a time to determine which are bad.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

  5. #5

    Member Sales Rating: (3)

    Join Date
    Aug 2004
    Posts
    285

    Default

    I tried plugging the preamp into a different outlet and the mechanical transformer hum is gone. The new outlet I tried is on a different circuit. I'm in an apt, so maybe there is some DC in my AC causing the coils in the transformer to get polarized.

    After this experiment, I'm assuming its not the tubes. But can someone confirm my hypothesis.

    Can anyone reccomend a power conditioner that cleans AC noise AND gets rid of DC?
    2 Channel

    Vandersteen 3a Sigs
    Music Reference RM-200
    Hovland HP-100
    VPI Scout w/ Benz Ace
    Rotel RCD-1072
    Cardas Golden Reference Speaker Cables
    Cardas Golden Reference Interconnects
    Cardas Golden Power Cords
    PS Audio UPC-200HB
    Black Diamond Racing Isolation

  6. #6

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,265

    Default

    No hum with old tubes. Hum with new tubes. No hum when plugged into different outlet with new tubes. I wonder if the hum would return if you put the old tubes back in while connected to the different outlet?

    You're making this more difficult than it has to be. Go back to the original outlet, replace the tubes one at a time, see what you come up with before doing anything else.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

  7. #7

    Member Sales Rating: (3)

    Join Date
    Aug 2004
    Posts
    285

    Default

    Quote Originally Posted by F1nut View Post
    No hum with old tubes. Hum with new tubes. No hum when plugged into different outlet with new tubes. I wonder if the hum would return if you put the old tubes back in while connected to the different outlet?

    You're making this more difficult than it has to be. Go back to the original outlet, replace the tubes one at a time, see what you come up with before doing anything else.
    Survey says...hum with old tubes in original outlet. No hum with original tubes in new outlet.

    F1nut, will NOS that are considered "new" need time break in? I feel like every damn time I sit down to listen, it sounds different. The frequency spectrum seems all over the place.
    Last edited by cbl117; 05-26-2007 at 12:29 AM.
    2 Channel

    Vandersteen 3a Sigs
    Music Reference RM-200
    Hovland HP-100
    VPI Scout w/ Benz Ace
    Rotel RCD-1072
    Cardas Golden Reference Speaker Cables
    Cardas Golden Reference Interconnects
    Cardas Golden Power Cords
    PS Audio UPC-200HB
    Black Diamond Racing Isolation

  8. #8

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,265

    Default

    Survey says...hum with old tubes in original outlet. No hum with original tubes in new outlet.
    Ah!


    Yes, they will need to burn in. 50 hours or so should do it.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Similar Threads

  1. Any one know what might be causing this?
    By millerman 3732 in forum Electronics
    Replies: 12
    Last Post: 11-02-2006, 12:19 AM
  2. Whats causing low hum...
    By Grimster74 in forum Electronics
    Replies: 6
    Last Post: 09-09-2006, 10:11 AM
  3. SDA-2 causing amp to shut down
    By OnlyPolk in forum Vintage Speakers
    Replies: 21
    Last Post: 07-16-2006, 01:47 PM
  4. csi5 causing dvd interference??
    By sammybocat in forum Troubleshooting
    Replies: 0
    Last Post: 12-27-2003, 04:22 PM
  5. Tranny question
    By RuSsMaN in forum Car Audio & Electronics
    Replies: 6
    Last Post: 12-11-2003, 07:52 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts