Strange sounds...

[Mephis]

I hear a strange "under pressure" sound comming from something on the preamp side of my 6505.

You know the sound air makes when being forced through a hose under pressure? That's what it sounds like. It doesn't come through the speakers.

Tapping on top of the amp does not affect it. And you can not get the sound unless you play hard with a little volume for a few minutes.

Am I dropping a preamp tube or what is going on? The tone is fine...

 

[WhoFan]

Re: Strange sounds...

very strange... my 5150, and my buddies 5150 have made some odd noises once in a while but nothing like you describe... Microphonic tube maybe? cap on the way out? Tranny trouble? i have no idea what would make the noise you describe

 

[Mephis]

Re: Strange sounds...

I don't have any microphonic issues and the amp sounds normal.

That's why it's confusing me. It's also brand new...

Could it just be the sound of high voltages inside the amp being built up?

 

[WhoFan]

Re: Strange sounds...

I don't have any microphonic issues and the amp sounds normal.

That's why it's confusing me. It's also brand new...

Could it just be the sound of high voltages inside the amp being built up?

not sure myself.... Jeff Seal or one of the other amp guys on here will be much more helpful then me on such matters...

To me it does not sound like a good thing.. Was the amp cold when it was fired up by chance?

 

[Mephis]

Re: Strange sounds...

It was at room tempture, between 60-75f.

It comes and goes inconsistantly. When a friend came by I couldn't get the amp to do it.

I tried tapping the amp harder and I can hear like a springy like sound comming from something in the preamp.

This doesn't cause feed back or nothing. Do I just have a microphonic tube in that case? And how would I tell which one? I have 6 lol.

 

[StrangeSound]

Re: Strange sounds...

I'm the troll in your amp! :banana:

Change the preamp tubes among each other. Although there are 6 of them I think the first 2 should be the most important then?

My amp has 4 and the V1 is the master blaster.

 

[Mephis]

Re: Strange sounds...

I'll give that a shot. I noticed it sounds almost like the wire inside of a light bulb when you shake it. Hard to describe over the sound of the amp.

 

[StrangeSound]

Re: Strange sounds...

I've had some issues with my Screamer aswell.

Sometimes the amp gives a hiss when I play something but it stops when I stop playing. I knocked on the amp a bit and it produced this hiss, too.

But it's okay now. Perhaps the tubes weren't perfectly in the cap and I checked every tube.

 

[cream123]

Re: Strange sounds...

Did you check if Brian May is in there?

(bada-tsss)
:chairfall

 

[WhoFan]

Re: Strange sounds...

my Peavey c50 head made an awful noise.... a high pitch squeal and it was a Pre amp Tube... I think it made the noise even when the amp was on standby. maybe trying a pre tube in each socket until you find the noisey one could be the cure...

 

[B2D]

Re: Strange sounds...

Did you check if Brian May is in there?

(bada-tsss)
:chairfall

Dammit! Beat me to it!