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Thread: whistling amp?

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    Mojo's Minions GuitarDoc's Avatar
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    Unhappy whistling amp?

    My amp will occassionaly start to make a whistle noise (like a tea pot) and other wierd noises. No regularity to the noises, just random. Even with the standby switch on. It's not very loud, but it is very annoying. Is there something wrong with the tubes, transformer, bias? What could be doing this?

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    Toneologist
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    Default Re: whistling amp?

    My first idea would be to check for a microphonic tube, but the fact that it does it even when in standby gives me pause, as the only thing that should have power when the amp is in standby is the heaters. If there's no power to the rest of any of the tubes, then I would think the tube could rattle all it pleased and it wouldn't make any noise.

    Still would be a good idea to check for a microphonic tube.

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    Minion of One Andrew Lamprecht's Avatar
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    Default Re: whistling amp?

    Don't put hot water in the amp!!!!
    Quote Originally Posted by crusty philtrum View Post
    Gear was simple, ya plugged in, turned up and played. The men were separated from the boys. Now it's mostly limp-wristed sissies wearing makeup and scowling at the camera. None of them would have cut it in the dinosaur days, they would have pooped their pants and run home to mummy.

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    Default Re: whistling amp?

    Quote Originally Posted by koreth View Post
    my first idea would be to check for a microphonic tube, but the fact that it does it even when in standby gives me pause, as the only thing that should have power when the amp is in standby is the heaters. If there's no power to the rest of any of the tubes, then i would think the tube could rattle all it pleased and it wouldn't make any noise.

    Still would be a good idea to check for a microphonic tube.
    +12
    Quote Originally Posted by crusty philtrum View Post
    Gear was simple, ya plugged in, turned up and played. The men were separated from the boys. Now it's mostly limp-wristed sissies wearing makeup and scowling at the camera. None of them would have cut it in the dinosaur days, they would have pooped their pants and run home to mummy.

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    Just Ultimate Slacker
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    Default Re: whistling amp?

    I thought this was a thread WANTING a whistling amp.
    Kinda like a guitar amp, but for whistling.............
    Quote Originally Posted by MikeS View Post
    a "career" of playing sold-out bedroom shows to the posters on my wall.
    Quote Originally Posted by JB_From_Hell View Post
    whats becoming of this generation
    We want to listen to music while we mow the lawn.

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    GuitarArtologist kmcguitars's Avatar
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    Default Re: whistling amp?

    With amp in standby ,The PT is obviously ON and putting voltage to the power supply (i.e.) (filter caps & rectification) and 6.3 v to the tube heaters. So check the tubes 1st, But my guess is a bad filter cap??

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    Mojo's Minions GuitarDoc's Avatar
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    Default Re: whistling amp?

    Quote Originally Posted by kmcguitars View Post
    With amp in standby ,The PT is obviously ON and putting voltage to the power supply (i.e.) (filter caps & rectification) and 6.3 v to the tube heaters. So check the tubes 1st, But my guess is a bad filter cap??

    This info sounds great. But I'm a newbee to tube amps. So how do I check the tubes, esp for a microphonic tube? How do I check the filter caps?

    I haven't been inside a tube amp before so I don't know my way around. All I really understand is that there are preamp tubes and power tubes and a transformer. Other than that, the amps guts are about as familiar to me as the circuits in a space ship.

    I guess I need more help than I thought. But thanks for your help and support thus far. You'll have to baby me through this.

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    Default Re: whistling amp?

    One more thing...

    While I'm playing it will start to make these weird noises. Not real loud, but certainly audible. If I stop playing the noise continues unaffected. If I flip the standby switch, it also continues unaffected. The noises come and go at random. Sometimes they will last only a couple seconds. Other times they will last 1/2 to 1 minute.

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    GuitarArtologist kmcguitars's Avatar
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    Default Re: whistling amp?

    Quote Originally Posted by GuitarDoc View Post
    This info sounds great. But I'm a newbee to tube amps. So how do I check the tubes, esp for a microphonic tube? How do I check the filter caps?
    YOU DON'T ! The filter caps is where the Lethal voltage is hiding.You can check the preamp tubes by gently tapping on them with a wooden chopstick,Or a pencil.If the tube is microphonic? You will hear a audible sound come from the speaker when you tap. If the tubes all check out? Then stop there, And get it to a tech.

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    Default Re: whistling amp?

    where are the noises coming from exactly?if they are coming from the speaker even when the amp is in standby something is very wrong.

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    Default Re: whistling amp?

    it probably needs new tubes but visit the tech just to make sure.

    you don't want to mess with it and make things worse or risk your life

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    Default Re: whistling amp?

    Quote Originally Posted by kmcguitars View Post
    YOU DON'T ! The filter caps is where the Lethal voltage is hiding.You can check the preamp tubes by gently tapping on them with a wooden chopstick,Or a pencil.If the tube is microphonic? You will hear a audible sound come from the speaker when you tap. If the tubes all check out? Then stop there, And get it to a tech.

    OK, I tried tapping, here's what I found...

    First of all, when I turn it on there is a very loud hum. Didn't notice this before.

    When I lightly tapped on the first tube on the left there was a pretty loud noise that sounded like I was tapping on the spkr cone. All the other tubes were quiet. Then I accidently found that tapping on the metal chasis also made this loud noise (with a metalic ringing added to it) followed by a scratchy echo for a second (like scratching the spkr cone).

    Any ideas?

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    Red face Re: whistling amp?

    Quote Originally Posted by GuitarDoc View Post
    OK, I tried tapping, here's what I found...

    First of all, when I turn it on there is a very loud hum. Didn't notice this before. I think it's getting much worse.

    When I lightly tapped on the first tube on the left there was a pretty loud noise that sounded like I was tapping on the spkr cone. All the other tubes were quiet. Then I accidently found that tapping on the metal chasis also made this loud noise (with a metalic ringing added to it) followed by a scratchy echo for a second (like scratching the spkr cone).

    Any ideas?
    Anyone?

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    Default Re: whistling amp?

    What amp are we talking about here?
    Now operating part time: Glassman Tube Amps...repairs, rebuilds, restorations & modifications of tube equipment.

    Still building: GlassMan Amplifiers (25 watt, all tube, single channel w/reverb, single 12" combo) and some more designs in the works.

    Located in Fort Wayne, IN


    Note: I've "parked" my website in case anyone has been looking for it. I moved locations and haven't updated the site to reflect this.

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    Default Re: whistling amp?

    Quote:
    Originally Posted by kmcguitars
    YOU DON'T ! The filter caps is where the Lethal voltage is hiding.You can check the preamp tubes by gently tapping on them with a wooden chopstick,Or a pencil.If the tube is microphonic? You will hear a audible sound come from the speaker when you tap. If the tubes all check out? Then stop there, And get it to a tech.




    OK, I tried tapping, here's what I found...

    First of all, when I turn it on there is a very loud hum. Didn't notice this before.

    When I lightly tapped on the first tube on the left there was a pretty loud noise that sounded like I was tapping on the spkr cone. All the other tubes were quiet. Then I accidently found that tapping on the metal chasis also made this loud noise (with a metalic ringing added to it) followed by a scratchy echo for a second (like scratching the spkr cone).

    Any ideas?

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    Just Ultimate Slacker
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    Default Re: whistling amp?

    replace the tube
    Quote Originally Posted by MikeS View Post
    a "career" of playing sold-out bedroom shows to the posters on my wall.
    Quote Originally Posted by JB_From_Hell View Post
    whats becoming of this generation
    We want to listen to music while we mow the lawn.

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    Mojo's Minions J Moose's Avatar
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    Default Re: whistling amp?

    What amp do you have?

    No amp should make ANY sort of noise when standby is in the "don't play" position, so what your describing is very odd...
    J. 'Moose' Kahrs
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    Quote Originally Posted by the guy who invented fire View Post
    All you need to make a record is a mic, some tape and maybe some bad reverb...

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    GuitarArtologist kmcguitars's Avatar
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    Default Re: whistling amp?

    It is ODD That a bad tube could wreak havoc as described in standby, But stranger thing have happen. So here is what you do. UNPLUG THE AMP! Gently Remove tube in question (set aside) Plug amp back in, Turn it on (without that tube) If it hums, chirps of even farts? Shut it down iImmediately ! Unplug it, Take it to a Amp Tech! You've got a sick amp that needs help.

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    Alnico 6/8 gibson175's Avatar
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    Default Re: whistling amp?

    In the manuals that come with mesa boogie amps comes some very sound advice:
    "If your light goes out, you should change the light bulb before you call the electrician and rewire your house." - or something like this....
    Tube amps are very reliable. Tubes are not so reliable. Always, check/replace the tubes before you do anything else.

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    Heel Whacker tone4days's Avatar
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    Default Re: whistling amp?

    Quote Originally Posted by GuitarDoc View Post
    I haven't been inside a tube amp before so I don't know my way around.
    most important line of the thread


    get professional help with the amp

    the voltages running around in there are potentially LETHAL

    while you are there, have the pro teach you how to do simple, safe checks of things

    but until you are taught by a competent pro, stay out of there

    good luck
    t4d
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