Tube rustling sound ,in se amp ????

[klipschoid]

1. question .My amp uses 1 6dj8 pre tube but amp has been making a rustling noise so i pulled the 6dj8 and turned it on and no noise,so i wonder if its that tube or an output tube,pins were clean and i didnt leave it on long ,could the pre have a bad internal joint? I ordered a nos sylvania to replace it.previously when it was doing it i had no input connected and moved the tubes around,to see if it was a pin problem,wiggled them,but no change ,rustling is out of my left channel,i crossed my el84 tubes left to right no change,still in left channel,btw its one el84 per ch not pp .So this leads me back to the pretube,i cant narrow further because it drives both channels ,thanks for any help or similar experiences
   
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   klipschoid

 

[maxhifi]

I think you're on the right path to try substituting a new tube as the first step. There's a possibility its a noisy resistor or something else, but trying a new tube is the smartest thing to do at this point.

 

[klipschoid]

Thankz appreciate the reply

 

[gadget73]

I've had noisy tubes before, usually it sounds like a wind blowing sort of sound. Swapping for another one is the easiest way to check for it.

 

[klipschoid]

Ok ,yes i have a nos sylvania 6dj8 pair coming,ill try.it has an old rca in it now.rca is good but it could be jus wearing out,internal dry joint on the left side of it ,etc.I cant offord telefunkens right now.If this fixes it i may save for some more tubes ,this amp plays plenty loud on my corns ,i may bi amp them later,if theres an easy way((6 ohm resistor maybe where the woofer was type of thing)),but i know this is not inductive like the woofer ,.and keep my triode on the mid-highs ,but prob not worth the trouble,bass is there if its meant to be,in the recording

 

[gadget73]

If you're going to bi-amp, it makes more sense to split the frequencies before the power amplifier. It makes it so the amp only has to reproduce what you need at the speaker rather than the whole frequency range and throwing away part of it. Basically its a line-level crossover.

 

[CZ4A]

I've noticed a rustling sound in a Tung-Sol black glass 12AU7 before, and it turned out to be an intermittent internal short. Putting silicone damper rings on the tube and cleaning the pins with Deoxit helped reduce the noise. If you can put that 6DJ8 on a tester you can check to see if it is shorting out.

 

[klipschoid]

Ok,ya no tester and ill see if swappin that 6dj8 will help ,almost like its emitting when it shouldnt ,thats with no input,if this doesnt help ill see if a resistor is going ,but its got decent allen bradley resistors and solen caps ive seen so far.But doesnt mean there cant be a cold solder somewhere,and gyrating the tubes in their sockets doesnt make it do it,so,ill post when i swap that 6dj8 ,thanks yall

 

[gadget73]

Some quick Google-fu tells me A-B stopped making resistors in the 1990s. Thats a fair long while ago.

 

[vonclod]

I'm watching this thread..I have a Sonic Frontiers integrated that does this..even with the mute switch on, have changed all the bottles too.

 

[gadget73]

if changing the tubes does nothing, plate resistors would be my next guess. Carbon comp resistors in particular tend to get funky like this.

 

[klipschoid]

Ok on the AB resistors,hope its just a tube,ill report when i get it in the mail and fired up again

 

[klipschoid]

Would yall think if its a resistor ,itd be a resistor on the preamp tube plate? It only does it in left channel,and of course not at all if the preamp tube isnt in,btw still learning tubes

 

[klipschoid]

And with no preamp tube in,those output tubes are still getting their b+ and no noise to be heard without that pretube in ,im jus narrowing it down my way ,lol ,but i proudly take advice as well

 

[Northwinds]

I've noticed a rustling sound in a Tung-Sol black glass 12AU7 before, and it turned out to be an intermittent internal short. Putting silicone damper rings on the tube and cleaning the pins with Deoxit helped reduce the noise. If you can put that 6DJ8 on a tester you can check to see if it is shorting out.

I was just going to suggest the damping ring then saw your post

 

[klipschoid]

Didnt do anything but push the amp hard yesterday and today no rustling,hmmm ,i think its getting rf interference from something,or the pre tube had a bit of air in it or moisture and now it has burnt up or dried up ,i dont know

 

[klipschoid]

So ya jus push your amp hard once in a while,try that ,only thing i can figure is the input grid on my pre tube is iffy,and pushin more voltage into it did something to it,because even pushing a tube amp harder doesnt heat it more like class ab does ,so any clue why pushin it would help?

 

[klipschoid]

My nos 6dj8 is coming today ,ill see if that quiets my amp down and ill post back

 

[Dadbar]

I've had that rustling noise happen with dirty tube pins. Clean and retension the sockets...that might fix it.

 

[klipschoid]

Ok thankyou