Follow us on...
Follow us on Twitter Follow us on Facebook Watch us on YouTube
Register
Page 1 of 2 12 LastLast
Results 1 to 15 of 20
  1. #1
    Banned!
    Join Date
    06.14.01
    Location
    New York
    Posts
    651
    Favorite VH Album

    MCMLXXXIV
    Favorite VH Song

    D.O.A.
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    I got a Marshall amp head and when I tried playing through it 10 minutes ago I got this massive ear-splitting interference coming through the cab when I turned the standby switch off and the first 2 power tubes in the head went from orange to purple in a split second. I'm just wondering if anyone has ever had this problem before and if so, what is it?

  2. #2
    Romeo Delight strangegrey's Avatar
    Join Date
    01.18.02
    Location
    Long Island, NY
    Posts
    96
    Favorite VH Album

    5150
    Favorite VH Song

    Dreams
    Last Online

    06.05.17 @ 08:59 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    Replace your tubes...

    when your tubes start changing colors like that, that means they're shot.

    -F

  3. #3
    Banned!
    Join Date
    06.14.01
    Location
    New York
    Posts
    651
    Favorite VH Album

    MCMLXXXIV
    Favorite VH Song

    D.O.A.
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    Originally posted by strangegrey:
    Replace your tubes...

    when your tubes start changing colors like that, that means they're shot.

    -F
    I changed the tubes 3 months ago. You think they'd already be shot? What about the interference... would dead tubes cause that?

  4. #4
    XTC man! homeunit's Avatar
    Join Date
    01.08.00
    Location
    Vancouver, Canada
    Posts
    4,113
    Favorite VH Album

    Cover Bands from Pasadena
    Favorite VH Song

    Babe Don't leave Me Alone
    Last Online

    09.05.15 @ 12:20 PM
    Likes
    29
    Liked 9 Times in 7 Posts

    Sounds like bum tubes to me bro.

  5. #5
    Top Of The World
    Join Date
    01.27.00
    Location
    USA
    Posts
    159
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    Those tubes are spanked [img]graemlins/scared.gif[/img]
    And beyond the horizon.... a sound was heard.

  6. #6
    Atomic Punk Wolfman's Avatar
    Join Date
    05.31.00
    Location
    Lexington, KY
    Posts
    8,119
    Favorite VH Album

    Fair Warning
    Favorite VH Song

    Hear About It Later, Atomic Pu
    Last Online

    07.20.17 @ 03:43 PM
    Likes
    0
    Liked 1 Time in 1 Post

    Take that sucker to a shop and make sure the tubes are matched and the amp is biased correctly.

    Also make sure that you let your amp sit in standby for at least 30 seconds before you turn it all the way on, and let it cool off in standby for a few minutes after playing - you'll save a lot of quick wear and tear on your tubes in the long run that way.

    [ February 26, 2002 at 01:54 PM: Message edited by: Wolfman ]</p>

  7. #7
    Good Enough
    Join Date
    02.21.00
    Location
    Canada
    Posts
    2,491
    Favorite VH Album

    Carnal Knowledge
    Last Online

    03.30.13 @ 09:28 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    What kind of interference? What did it sound like?
    Was it squealing, or a rattling sound, or what?
    Does your amp have reverb?

  8. #8
    Banned!
    Join Date
    06.14.01
    Location
    New York
    Posts
    651
    Favorite VH Album

    MCMLXXXIV
    Favorite VH Song

    D.O.A.
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    The interference is a really bad and loud squealing noise. I even turned all the knobs on the amp down to "0" and I still got this noise. The amp has reverb but I'm almost positive the noise I'm getting isn't something associated with a reverb spring rattling or anything like that. When the standby is on, the amp is totally quiet like it should be but when I switch the standby off to get the amp running all of a sudden that squealing shit starts and at the same time the first 2 power tubes immediately heat all the way up. What I don't understand is why this happened when I first turned the amp on when I had played through the amp 3 hours the day before with no problems.

  9. #9
    Good Enough
    Join Date
    02.21.00
    Location
    Canada
    Posts
    2,491
    Favorite VH Album

    Carnal Knowledge
    Last Online

    03.30.13 @ 09:28 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    That squealling sounds like a preamp tube is shot or extremely microphonic. The power stage will just amplify it. Tubes are just like light bulbs. They can weaken with age, or burn out anytime.
    I'd replace the preamp tubes one at a time first, and then get your amp in and get it biased.
    Power amp tubes always glow much hotter than preamp tubes but if they're really lighting up, and you don't do anything about it you might fry something in there.
    If your power amp tubes are as hot as you say then they're probably 70% fried anyway.
    First get one good preamp tube and replace them one at a time, then if the squealing goes away have another look at your power tubes.
    Is it a 100 watt head?

  10. #10
    Top Of The World
    Join Date
    01.27.00
    Location
    USA
    Posts
    159
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    I have somewhat of a similar problem with my Marshall 365 combo except I get a lot of "popping" noises, mostly when I put any bottom end in the mix. So I don't really have a clue as to what my problem is. It mostly does it on the clean and 3rd channel. Not so noticeable on the middle gain channel. [img]graemlins/irked.gif[/img]
    And beyond the horizon.... a sound was heard.

  11. #11
    Good Enough
    Join Date
    02.21.00
    Location
    Canada
    Posts
    2,491
    Favorite VH Album

    Carnal Knowledge
    Last Online

    03.30.13 @ 09:28 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    Does the popping occur when you strike a note, almost like there's a pop just as or before the note sounds?
    Do you have reverb, and does it still pop with the reverb turned off?

  12. #12
    Banned!
    Join Date
    06.14.01
    Location
    New York
    Posts
    651
    Favorite VH Album

    MCMLXXXIV
    Favorite VH Song

    D.O.A.
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    Originally posted by tribb:
    That squealling sounds like a preamp tube is shot or extremely microphonic. The power stage will just amplify it. Tubes are just like light bulbs. They can weaken with age, or burn out anytime.
    I'd replace the preamp tubes one at a time first, and then get your amp in and get it biased.
    Power amp tubes always glow much hotter than preamp tubes but if they're really lighting up, and you don't do anything about it you might fry something in there.
    If your power amp tubes are as hot as you say then they're probably 70% fried anyway.
    First get one good preamp tube and replace them one at a time, then if the squealing goes away have another look at your power tubes.
    Is it a 100 watt head?
    Yeah, the head is 100 watts. One problem I've had since the day I started buying equipment and going to music stores is a serious lack of help as far technical advice and customer service is concerned. This just about applies to any music store that is 50 miles north, south, east or west of me. I hate those mutherfuckers who work in those stores with a passion and the reason why is because they basically refuse to help you and this has to do with the fact that they honestly don't know what they're talking about either. A matter of fact the last time I bought tubes I mentioned biasing the amp in passing to the person I was with and the douchebag at the accessories counter says, "don't even ask about biasing, that's a big job and no one here wants to do it." As far as preamp tubes go, I've always been under the impression that biasing is not needed for these, just power tubes. Is this correct?

  13. #13
    Good Enough
    Join Date
    02.21.00
    Location
    Canada
    Posts
    2,491
    Favorite VH Album

    Carnal Knowledge
    Last Online

    03.30.13 @ 09:28 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    Yup. Your preamp is self biasing. As long as you use 12ax7's, ecc83's, 7025's, etc., basically the same type of tube with different gain characteristics the preamp will self bias, so don't worry about that.
    Biasing a marshall head is absolutely necessary when going to a different rated power tube, or different manufactured power tubes. It's just the power amp section that has to be biased, and it's not a big job at all for a service tech.
    If your head is a 100 watter, and 2 tubes on one side are heating in tandem, and reacting differently than the other two then you could have a problem with the power grid. Have the head checked out as soon as you can by someone competent to work on it. The high pitch whistle could still be a faulty preamp tube.
    Did you change any of the preamp tubes to see what happens?

  14. #14
    Banned!
    Join Date
    06.14.01
    Location
    New York
    Posts
    651
    Favorite VH Album

    MCMLXXXIV
    Favorite VH Song

    D.O.A.
    Last Online

    12.31.69 @ 04:00 PM
    Likes
    0
    Liked 0 Times in 0 Posts

    Ok thanks for the help man, I appreciate it. I'm gonna change the preamp tubes relatively soon and bring the amp to the shop to have it biased and checked out. From what I've told you, does it sound like there might be any unfixable damage on the amp or should I be able to have everything taken care of?

  15. #15
    XTC man! homeunit's Avatar
    Join Date
    01.08.00
    Location
    Vancouver, Canada
    Posts
    4,113
    Favorite VH Album

    Cover Bands from Pasadena
    Favorite VH Song

    Babe Don't leave Me Alone
    Last Online

    09.05.15 @ 12:20 PM
    Likes
    29
    Liked 9 Times in 7 Posts

    Originally posted by AxeSlinger84:
    Ok thanks for the help man, I appreciate it. I'm gonna change the preamp tubes relatively soon and bring the amp to the shop to have it biased and checked out. From what I've told you, does it sound like there might be any unfixable damage on the amp or should I be able to have everything taken care of?
    You be able to have everything taken care of, me thinks
    My Band
    Baluchitherium

 

 

Similar Threads

  1. tube question
    By solo-ed in forum Guitar Room
    Replies: 6
    Last Post: 07.18.06, 09:12 AM
  2. check me out on you tube
    By RG550L in forum VH Fans Meeting Place (Music Only)
    Replies: 0
    Last Post: 04.26.06, 04:53 PM
  3. Blew my first tube...
    By White Lightning in forum Guitar Room
    Replies: 6
    Last Post: 04.18.06, 04:47 AM
  4. 5150 Head Tube problem
    By tribb in forum Guitar Room
    Replies: 3
    Last Post: 02.02.03, 10:27 PM
  5. tube questions
    By stratogibson in forum Guitar Room
    Replies: 8
    Last Post: 05.01.01, 05:33 AM

Tags for this Thread

Posting Permissions

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