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So if you tap a preamp tube and noise comes out of the speakers...


mparsons

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It's microphonic and bad, right?


The tubes I ordered from Doug are already microphonic. I think I've had them for two weeks. Is this normal? Or should I be contacting him for a replacement?

 

 

no, you are wrong!

 

Man so many people are misinformed about this..

 

The tube will make noise when you hit it. Stop doing that!!! haha

The tube is microphonic if it continues to oscillate after you tap the tube. I.E- Feedback.. If the tube does not feedback after tapping it, but you hear the noise of you hitting the tube, then its fine.. The tube is AMPLIFYING the sound.

 

The best way to find out if a tube is microphonic to the point of replacement is to turn your amp all the way up(or as loud as you will ever play it), play a few big chords or whatever then turn off your guitar.. Does it start to feedback? If not, you are fine.. If it does start to oscillate/feedback, try a new tube, or switch this tube to a different slot...

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no, you are wrong!


Man so many people are misinformed about this..


The tube will make noise when you hit it. Stop doing that!!! haha

The tube is microphonic if it continues to oscillate after you tap the tube. I.E- Feedback.. If the tube does not feedback after tapping it, but you hear the noise of you hitting the tube, then its fine.. The tube is AMPLIFYING the sound.


The best way to find out if a tube is microphonic to the point of replacement is to turn your amp all the way up(or as loud as you will ever play it), play a few big chords or whatever then turn off your guitar.. Does it start to feedback? If not, you are fine.. If it does start to oscillate/feedback, try a new tube, or switch this tube to a different slot...

If it just makes a really harsh glassy sound when you tap it, it can be a bit microphonic. Byt, they should make noise, with the first ones in the chain being louder ordinarily. And use a pencil or something not quite as hard. And gently.

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no, you are wrong!


Man so many people are misinformed about this..


The tube will make noise when you hit it. Stop doing that!!! haha

The tube is microphonic if it continues to oscillate after you tap the tube. I.E- Feedback.. If the tube does not feedback after tapping it, but you hear the noise of you hitting the tube, then its fine.. The tube is AMPLIFYING the sound.


The best way to find out if a tube is microphonic to the point of replacement is to turn your amp all the way up(or as loud as you will ever play it), play a few big chords or whatever then turn off your guitar.. Does it start to feedback? If not, you are fine.. If it does start to oscillate/feedback, try a new tube, or switch this tube to a different slot...

 

+1, power tubes are the only ones that shouldn't make any noise when lightly tapped. Preamp tubes will make noise, especially the input tube.

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Only the preamp tubes make any noise when tapped. They make a rattling noise. When I'm playing the amp loud, I can hear the tubes rattling around when I'm playing the guitar.

 

 

If the tubes are rattling and you can hear them in your amp then that isnt right either.. Although microphonic means something different than a poorly constructed rattling tube.. FWIW, I had some old tubes that rattled and when I put them in my amp they SCREAMED like a banshee. They were microphonic and bad beyond belief. So I couldnt tell you whats going on, if your amp sounds ok but you're hearing rattling.. I would suspect its prolly only 1 tube, so maybe try and find the bad tube..

 

Otherwise call Doug and explain, tubes do go bad during transit.,

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When I plug the guitar straight into the power amp and crank it I can hear the tube rattling through the speakers
:freak:

 

What are you doing plugging straight into the power amp section from the effects loop return?

 

I think your making a mountain out of a mole hill. The pre tubes with make a tapping sound when you tap them. If you want a louder tapping sound use a hammer. HE HE HE

 

Kind of like saying a spring reverb is bad cause it makes a lot of noise when I smack the side of my amp.

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No :lol: This isn't an amp head. This is my VHT 2/90/2 power amp. It has two phase inverter tubes and two preamp tubes ( I assume for the presence/depth knobs )

 

I narrowed it down to a rattling Shuguang tube. I removed it and replaced it with a spare tube I had laying around. No more rattle. All is well.

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