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 23

Thread: 5150 II Go Boom

  1. #1
    Forum Frontman
    Join Date
    09.15.06
    Age
    42
    Location
    Minneapolis
    Posts
    6,568
    Last Online

    07.04.16 @ 08:03 PM
    Likes
    3
    Liked 6 Times in 5 Posts

    Default 5150 II Go Boom

    Hey All:

    Wasn't it just a couple of weeks ago we were coaching one of our members on how to turn on/off his 5150 so as to not do it damage? Well... not quite the same thing, but I effed up my 5150 II head last night at a gig and wanted to get some opinions on what I should look out for.

    The quick story: I set up as normal for the show. The live rig is a 5150 II head into a JCM 900 1960B cab. My pedalboard goes through the effects loop and my guitar plugs straight into the input. I've been letting another guitar player use my cab at our rehearsal space, however, and it was set the "stereo" mode, which I believe makes it 8 ohms. I run the 5150 II at 16 ohms. I failed to make note of this while setting up, and about halfway through the show my volume suddenly cut way down. My immediate reaction was to kill the effects loop, since a volume drop like that typically indicates a bad cable. No change, though. I messed with my guitar cable and guitar jack. No change. It was too difficult in the way the stage was set up to get a look at the power tubes in the amp, but I was able to crank the volume up and ride out the rest of the show. It sounded an awful lot like I lost a couple of power tubes. I dumped my gear back in our rehearsal space after the show and haven't been back to test it, but I remembered seeing the switch on the cab in the wrong position when hauling my stuff out of the club.

    So the question is: By mismatching ohms did I simply drive the power tubes too hard and blow one or more of them, or is there a chance I did more serious damage like to the output transformer? I was hoping some of our more knowledgeable amp guys here can tell me what to look for to verify there aren't problems beyond tubes.

    Thanks in advance, guys.

  2. #2
    Unchained 5150jeff's Avatar
    Join Date
    09.01.07
    Age
    51
    Location
    Michigan
    Posts
    526
    Favorite VH Song

    I'm the one
    Last Online

    01.06.11 @ 05:09 PM
    Likes
    0
    Liked 0 Times in 0 Posts


    Donor

    Default

    Hmm,sounds more like the preamp sec but try this,set your ohms to the right setting,then plug a cable from your guitar directly to your effects return jack,now you are only using your power amp,any change?louder, if so its its not in the power section,if it stays the same something else is amiss.
    Last edited by 5150jeff; 10.17.09 at 09:38 PM.

  3. #3
    Baluchitherium
    Join Date
    02.19.07
    Posts
    4,976
    Last Online

    10.01.15 @ 06:45 PM
    Likes
    99
    Liked 179 Times in 57 Posts

    Default

    Hmm.. I don't have the solution for you but this is somewhat related..?

    I have a 5150 head not a II and run it through a JCM800 1960a cab.
    The cab says 16 ohms on it and I run the 5150 on 16 ohms...I thought you run it on 8 ohms when using two 16 ohm cabs..?


    Last monday at rehearsal my signal seemed a tad weak when I turned the loop off the volume jumped up big time. I messed with the pedals in the loop...I then unplugged the two cables send and return to loop and put them back in then it all started working properly...brand new cables pretty much.

    Thing is a week ago or so I noticed my ohm setting was on 4 and I have no idea how long it was that way. Maybe a few days, maybe a few weeks. I'm more mindful of it now but when breaking down or setting up often bandmates etc help carry stuff and that switch on the back must have gotten moved.

    I leave that gear ready to go out for rehearsal so haven't tested it again since Monday night...but that alarmed me. My plan is before we get out gigging properly to get the head totally looked at and retubed biased and all that. I'm hoping this was just a bad cable connection or something but I fear it may be something worse and it sounds exactly like whatever you are experiencing.

    I'll keep an eye on this thread if you find out anything more definitive and I'll chime in again if the problem persists and gets solved or is revealed when getting it serviced.

    Good luck. At least you could finish your gig with it.
    [SIGPIC][/SIGPIC]

  4. #4
    Baluchitherium
    Join Date
    09.11.06
    Age
    41
    Location
    Leicestershire, England
    Posts
    4,484
    Favorite VH Album

    VH1, VHII or Fair Warning
    Favorite VH Song

    They're all great!
    Last Online

    04.02.15 @ 07:26 AM
    Likes
    0
    Liked 5 Times in 2 Posts


    Donor

    Default

    stupid question....have you tried changing ALL the tubes? both preamp and power tubes to see if this cures/alters anything.

    i was always under the impression that you could run a lower rated cab (say for instance 8ohms) while you were set at 16ohms but NOT vice versa as you run the risk of killing the output transformer, for this reason i always taped the switch in position (and checked it regularly), sorry i can't be of more help, Mrj is pretty shit hot at this stuff maybe he'll chime in at some point or you could pm him.

    anyway mate good luck with getting it sorted.

    Tom
    http://www.facebook.com/Tommywho5150

    And with that I'm off to the kitchen to make myself a lesbian omelette...LLFHS in response to one of Graeme's post's


    "The anal beads may have scarred SNIC for life. That guy is tough as fucking nails!! No normal guy could take anal beads to the head and survive! "...OLO on SNIC's near death experience at TLW

    "I'm a 45-year-old man, and I still like to wear a thong or a speedo when I go swimming.
    Not because I have a great body, it's just an easy way to make sure I have the hotel swimming pool all to myself."...Bullwinkle for quite obvious reasons!

    "Dude, the cashier gave me the creepiest sneer when he rang up my unmentionables!"...Sassy Lassy during a Facebook conversation!

  5. #5
    Unchained 5150jeff's Avatar
    Join Date
    09.01.07
    Age
    51
    Location
    Michigan
    Posts
    526
    Favorite VH Song

    I'm the one
    Last Online

    01.06.11 @ 05:09 PM
    Likes
    0
    Liked 0 Times in 0 Posts


    Donor

    Default

    Quote Originally Posted by At0micPunk View Post
    Hmm.. I don't have the solution for you but this is somewhat related..?

    I have a 5150 head not a II and run it through a JCM800 1960a cab.
    The cab says 16 ohms on it and I run the 5150 on 16 ohms...I thought you run it on 8 ohms when using two 16 ohm cabs..?


    Last monday at rehearsal my signal seemed a tad weak when I turned the loop off the volume jumped up big time. I messed with the pedals in the loop...I then unplugged the two cables send and return to loop and put them back in then it all started working properly...brand new cables pretty much.

    Thing is a week ago or so I noticed my ohm setting was on 4 and I have no idea how long it was that way. Maybe a few days, maybe a few weeks. I'm more mindful of it now but when breaking down or setting up often bandmates etc help carry stuff and that switch on the back must have gotten moved.
    running two mono 16ohm cabs you would cut the ohms in half,so yes the correct setting would be 8 ohms,also you effects loop jacks often get cruddy,that would explain when you reinserted the cables it started to work properly again,you got a better connection,just clean the effects send and return jacks by spraying a little deoxit contact cleaner on a cable end and work it in and out of both jacks.

  6. #6
    Unchained 5150jeff's Avatar
    Join Date
    09.01.07
    Age
    51
    Location
    Michigan
    Posts
    526
    Favorite VH Song

    I'm the one
    Last Online

    01.06.11 @ 05:09 PM
    Likes
    0
    Liked 0 Times in 0 Posts


    Donor

    Default

    Quote Originally Posted by tommywho5150 View Post
    i was always under the impression that you could run a lower rated cab (say for instance 8ohms) while you were set at 16ohms but NOT vice versa as you run the risk of killing the output transformer,

    Tom
    It's the other way around,if your head is set at say 8ohms and the cab is 16ohms it wont hurt it,you will just loose a little power,volume.

  7. #7
    Baluchitherium
    Join Date
    02.19.07
    Posts
    4,976
    Last Online

    10.01.15 @ 06:45 PM
    Likes
    99
    Liked 179 Times in 57 Posts

    Default

    Quote Originally Posted by 5150jeff View Post
    It's the other way around,if your head is set at say 8ohms and the cab is 16ohms it wont hurt it,you will just loose a little power,volume.
    Thanks for the info on this and my problem posted above!

    I'm relieved to hear your suggestions. Glad to hear that the low setting doesn't mess with a higher ohm rated cab. The 5150 ohm choices are 16 8 and 4 and the cab I use is 16 so no way even if it gets moved again can it do damage.

    One less thing to worry about..lol

    Hope I didn't hijack this at all...my problem seemed very similar.
    I hope this is in fact what it is, a bad loop connection and it's that simple for AT as well.
    [SIGPIC][/SIGPIC]

  8. #8
    Unchained 5150jeff's Avatar
    Join Date
    09.01.07
    Age
    51
    Location
    Michigan
    Posts
    526
    Favorite VH Song

    I'm the one
    Last Online

    01.06.11 @ 05:09 PM
    Likes
    0
    Liked 0 Times in 0 Posts


    Donor

    Default

    Well you should always run with matched ohms,you might be able to get away with a little mismatch,but you don't want to stray to far,not good for the tranny,or tubes for that fact.

  9. #9
    Forum Frontman
    Join Date
    09.15.06
    Age
    42
    Location
    Minneapolis
    Posts
    6,568
    Last Online

    07.04.16 @ 08:03 PM
    Likes
    3
    Liked 6 Times in 5 Posts

    Default

    Quote Originally Posted by At0micPunk View Post
    Thanks for the info on this and my problem posted above!

    I'm relieved to hear your suggestions. Glad to hear that the low setting doesn't mess with a higher ohm rated cab. The 5150 ohm choices are 16 8 and 4 and the cab I use is 16 so no way even if it gets moved again can it do damage.

    One less thing to worry about..lol

    Hope I didn't hijack this at all...my problem seemed very similar.
    I hope this is in fact what it is, a bad loop connection and it's that simple for AT as well.
    I don't mind at all when we venture off on similar issues in related threads. I learn a lot about stuff when that happens.

    I won't have a chance to mess with my 5150 II again until later this week. I've got different rigs for different projects, and tonight is all about prepping a solo show for a webcast tomorrow night. I'll be using my Laney for that gig.

  10. #10
    Good Enough
    Join Date
    12.15.07
    Location
    Iowa/Illinois
    Posts
    1,807
    Favorite VH Album

    Balance
    Last Online

    10.26.16 @ 03:37 PM
    Likes
    2
    Liked 0 Times in 0 Posts

    Default

    Ok, AT:

    Usually, running a head at 16 ohms into a 8 ohm load will not kill anything, *BUT* it can. The 5150 is built like a tank and usually that kind of thing for a little while wouldn't hurt it. However, playing an entire show at full blast may have been enough to fry something in your power section. The first things that can go are your power tubes, the surrounding circuit, and the output tranny. I would first retube at least the power section -- even if you put used/old, but known working tubes in there. Keep a REALLY close eye on it and test it up to volume if it seems ok low.

    Another possibility is that your power section is fine, the ohm mismatch didn't hurt it, and one of your preamp tubes is going out.

    So really, I'd retube the whole amp. If the problem is still there, then you probably got some power amp/output transformer damage. Let me know what else you find out when you test it.

  11. #11
    Hot For Teacher
    Join Date
    07.26.02
    Age
    44
    Location
    northwest Indiana(near chicago IL)
    Posts
    293
    Favorite VH Album

    vanhalen 1
    Favorite VH Song

    panama
    Last Online

    11.06.14 @ 03:09 AM
    Likes
    0
    Liked 0 Times in 0 Posts

    Default

    check tubes first,its my guess of where the problem is..
    stan

  12. #12
    Good Enough
    Join Date
    12.15.07
    Location
    Iowa/Illinois
    Posts
    1,807
    Favorite VH Album

    Balance
    Last Online

    10.26.16 @ 03:37 PM
    Likes
    2
    Liked 0 Times in 0 Posts

    Default

    Quote Originally Posted by mrjstudios View Post
    Ok, AT:

    Usually, running a head at 16 ohms into a 8 ohm load will not kill anything, *BUT* it can. The 5150 is built like a tank and usually that kind of thing for a little while wouldn't hurt it. However, playing an entire show at full blast may have been enough to fry something in your power section. The first things that can go are your power tubes, the surrounding circuit, and the output tranny. I would first retube at least the power section -- even if you put used/old, but known working tubes in there. Keep a REALLY close eye on it and test it up to volume if it seems ok low.

    Another possibility is that your power section is fine, the ohm mismatch didn't hurt it, and one of your preamp tubes is going out.

    So really, I'd retube the whole amp. If the problem is still there, then you probably got some power amp/output transformer damage. Let me know what else you find out when you test it.
    Still check the stuff above, but to add onto that (now that I think about it) what brand preamp tubes are in your amp? Electro harmonix or 2-4 year old JJ's?? I have a hunch....

  13. #13
    Good Enough SLEEPER5150's Avatar
    Join Date
    02.13.08
    Location
    Canada's West Coast
    Posts
    2,281
    Favorite VH Album

    Fair Warning
    Favorite VH Song

    Hear about it later
    Last Online

    12.03.10 @ 03:16 PM
    Likes
    0
    Liked 3 Times in 3 Posts

    Default

    Quote Originally Posted by AndrewThomas.net View Post
    I don't mind at all when we venture off on similar issues in related threads. I learn a lot about stuff when that happens.

    I won't have a chance to mess with my 5150 II again until later this week. I've got different rigs for different projects, and tonight is all about prepping a solo show for a webcast tomorrow night. I'll be using my Laney for that gig.
    Hey AT. Any word on your amp? BTW....this may sound a little funny, but out of curiosity.......did you notice if there was there any odor coming from the amp? Usually if you kill something electrical like a tranny or a cap, you'll notice a fairly caustic smell from the materials used to insulate the component.THis happened in a power amp I had in a rack. It started to drop it's volume, then there was this loud hum that started, then a bang with smoke. It reaked like a combination of plastic and tar. When I took the top grill off, you could see this black stuff that oozed out around the output tranformer. It's usually the insulation that melts that allows the unit short and fail. I know it's fairly obvious, but you did'nt mention any thing like this I don't think, which leads me to believe it's most likely a failed tube/s, and not a major component. Fingers crossed for you though.
    Last edited by SLEEPER5150; 10.19.09 at 10:39 AM.
    She looks so $#@!'n good ,so sexy and so frail....Somethin's got the bite on me, I'm goin' straight to Hell.

  14. #14
    Forum Frontman
    Join Date
    09.15.06
    Age
    42
    Location
    Minneapolis
    Posts
    6,568
    Last Online

    07.04.16 @ 08:03 PM
    Likes
    3
    Liked 6 Times in 5 Posts

    Default

    Quote Originally Posted by mrjstudios View Post
    Still check the stuff above, but to add onto that (now that I think about it) what brand preamp tubes are in your amp? Electro harmonix or 2-4 year old JJ's?? I have a hunch....
    Electro-Harmonix all the way--good hunch. (I get EH tubes at dealer cost.) I re-tubed the whole amp in about mid-2006. Considering I only play it once every couple of weeks, it's been doing well. But if I have to replace tubes it's not the end of the world.

  15. #15
    Forum Frontman
    Join Date
    09.15.06
    Age
    42
    Location
    Minneapolis
    Posts
    6,568
    Last Online

    07.04.16 @ 08:03 PM
    Likes
    3
    Liked 6 Times in 5 Posts

    Default

    Quote Originally Posted by SLEEPER5150 View Post
    Hey AT. Any word on your amp? BTW....this may sound a little funny, but out of curiosity.......did you notice if there was there any odor coming from the amp? Usually if you kill something electrical like a tranny or a cap, you'll notice a fairly caustic smell from the materials used to insulate the component.THis happened in a power amp I had in a rack. It started to drop it's volume, then there was this loud hum that started, then a bang with smoke. It reaked like a combination of plastic and tar. When I took the top grill off, you could see this black stuff that oozed out around the output tranformer. It's usually the insulation that melts that allows the unit short and fail. I know it's fairly obvious, but you did'nt mention any thing like this I don't think, which leads me to believe it's most likely a failed tube/s, and not a major component. Fingers crossed for you though.
    I didn't notice anything funny smelling right away, nor did I notice the amp running extra hot. But I also wasn't thinking the problem was with the amp. Initially I thought it was a bad cable, hence I was trouble-shooting from that perspective. (This was all literally mid-song.) Once I realized I could crank the output gain up and still have decent tone, I just went with that and rode it out to the end of the show. Only after bringing my cab back to our practice space did I discover the switch set incorrectly.

 

 

Similar Threads

  1. Massachusetts High School Faces Pregnancy Boom
    By voivod in forum VH Fans Meeting Place (Non-Music)
    Replies: 30
    Last Post: 06.21.08, 01:43 PM
  2. 5150 / 5150 II / 5150 212 Combo Comparisons
    By AT in forum Guitar Room
    Replies: 6
    Last Post: 01.29.07, 12:38 PM
  3. Rare photo of Space Shuttle Sonic Boom
    By Dennis in forum VH Fans Meeting Place (Non-Music)
    Replies: 17
    Last Post: 01.15.06, 04:33 AM
  4. Movie score with 5150 riffs...pre 5150
    By swage in forum Main VH Discussion
    Replies: 11
    Last Post: 02.02.03, 05:30 PM
  5. Tony Hawk Boom Boom
    By el_jalepeno in forum VH Fans Meeting Place (Non-Music)
    Replies: 0
    Last Post: 10.19.02, 07:55 PM

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
  •