[pzm9pzm9]

My WA2 have developed a humming sound recently. I know I am supposed to have a little hum from tubes as the volume gets pretty high, but this hum was irrelevant to the volume. I thought one of my tungsol 5998 was dead as I was able to hear the hum swithing from right to left while swapping them. (regardless of volume, without music) I did not hear any hum when switched tungsol tubes to other equivalent tubes. (RCA 6as7g)
Anyway, in my case, I gave some time for tubes warm up. (much longer than usual) and the hum suddenly disappeared. It was really strange.
I found out the hum went away after ordering a new pair of tungsol.... !!!!!
I would suggest try some more time with it. It may just go away magically like mine did. good luck!

 

[moonboy403]

Alternatively, you can also try tapping on the tubes if they hum. It works like magic for me most of the time.

 

[Anouk]

Hello, yes very strange that! Sometimes some of the hum indeed goes away if i tap the preamp tubes, i thought this would be a rather bad habbit though and not really good for tube life!
Also, i think in the past i could not hear the tubes but not if i tap the preamp tubes I can hear it in my headphones.
Greetings, Anouk,

 

[Anouk]

Well to clarify, if i tap the tubes sometimes the random noise goes away, not the hum itself.

 

[GuyDebord]

Its very probable that the tubes are causing this, try changing them.
Anouk, I doubt the dampers will help with this.

Are any of you close to a tv/coax outlet? if yes, try disconnecting the cable in the outlet. Coax cables are frequently the source of noise in sensitive equipment... hope it helps

 

[takezo]

Quote:

Originally Posted by Anouk /img/forum/go_quote.gif Hello, someone suggested in a pm to try tube dampers. I am, very new to tube amps, anyone know if this might make a difference? Greetings, Anouk

no, tube dampers don't help with humming tubes. the humming one hears
thru headphones caused by tubes is electrical in nature and not physical vibration nor oscillations.

 

[Skylab]

I cannot imagine tube dampers solving these problems, no. They will sometimes quiet a slightly microphonic tube, but that's about it.

 

[holland]

I have encountered some problems with some tubes, it's a scratchy type of sound. That sounds like it may be the same issue in this thread. A fluctuation in intensity and frequency. It's not the hiss or buzz. It's definitely tube related. I've had 3 Amperex 6DJ8s and 2 Tungsram ECC82s make this noise on me. A tube swap rectified the issue.

FWIW.

 

[strangelove]

I rechecked if the hum gets louder with adjusting the volume knob and it does. Maybe it is bad tubes.

 

[holland]

WooAudio 4 - Single-Ended Triode Class-A Vacuum Tube Headphone Amplifier

The large tubes are your EZ80. These are voltage rectifiers. If they go bad, they will pollute the entire amp. The power rails are *everything*. Those are the ones in the back row on the outer sides. The back row middle are likely the drive tubes (12AU7). The front row are likely the power tubes (6C19).

It sounds like you have 2 problems. You have a wow and flutter (not real wow and flutter like a phono player, just using it to describe what I think you are saying) and a buzz. The flutter, you said moves with the EZ80 tubes? The buzz, occurs constantly and changes with the volume knob?

The wow and flutter is a tube issue, since it moves with the tube.

The buzz is an input problem and/or wiring and/or ground issue, but most likely wiring. That is, since the pot affects it, it is the wiring from the pot, to the input switch and/or the switch to the jacks in the back.

1) Replace the EZ80, heck they are cheap, replace them both.
2) Does the wow and flutter remain?
3) If the wow and flutter go away, and if the problem(s) persist with the buzz and the knob go to 4. Trying to solve multiple problems at once is not a good idea. If the wow and flutter is still there, rediagnose or continue on with 4 and see if it changes the other aspects.
4) Move the amp to a different room, a different floor, power up, does it still buzz and does it change with the knob?
5) Ground the jacks. Connect the middle of the RCA jack to the outer jacket, just short it. That will put the input signal to ground.
- Does the problem still occur?
- Does the problem change with different input jacks selected on the front knob?

I'm sorry to say, that unless you're proficient with working on tube amps, this problem may be beyond a solution for you as it will and/or may require opening up. You're dealing with high voltage and live AC. Do not do this unless you know what you're doing. You can die easily.

Since you're in Pasadena, you may be able to find someone to help you out. You may want to follow up in the DIY section after you get the additional info, but I can't guarantee that.

 

[Anouk]

Hello, thanks for the help, I am crossing my fingers and biting my naisl that new tubes and a new power cord will do something at least for the wow and flutter as you put it and the static because these are the most irritating to me. You were right when you described the tube placement btw. As I said i had less hum problems with a less sensitive headphone (i was using the ultrasone pro900 and am now using the jvcdx1000 which will be sent away on monday). I still will have to find something to replace the jvc though so I can continue testing.
Greetings, Anouk,

 

[Anouk]

I just returned home after a weekend away. I notice that the stacis is there when i turn on the amp and if i leave it running without music. But if I start playing music for a while the static at least goes away and i dont listen at high volumes so the hum is not really noticable at this volume level. The random noise also goes away for the most part after a bit of playing music although it also jus tmight not be very noticable anymore.
Greetings, Anouk,

 

[holland]

Interesting, Anouk. I've found that noise never goes away and I have to toss the tubes.

 

[mrarroyo]

If it is hum related try a cheater which you can buy for under $3 at a pharmacy or Lowes/Home Depot.

I have also had tubes that needed the pins cleaned or the socket tightened to solve connection problems. Lastly some tubes will take 20-30 hours to settle and the noise will disappear, since this is a free tweak it might be worth exploring.

 

[strangelove]

Quote:

Originally Posted by holland /img/forum/go_quote.gif WooAudio 4 - Single-Ended Triode Class-A Vacuum Tube Headphone Amplifier The large tubes are your EZ80. These are voltage rectifiers. If they go bad, they will pollute the entire amp. The power rails are *everything*. Those are the ones in the back row on the outer sides. The back row middle are likely the drive tubes (12AU7). The front row are likely the power tubes (6C19). It sounds like you have 2 problems. You have a wow and flutter (not real wow and flutter like a phono player, just using it to describe what I think you are saying) and a buzz. The flutter, you said moves with the EZ80 tubes? The buzz, occurs constantly and changes with the volume knob? The wow and flutter is a tube issue, since it moves with the tube. The buzz is an input problem and/or wiring and/or ground issue, but most likely wiring. That is, since the pot affects it, it is the wiring from the pot, to the input switch and/or the switch to the jacks in the back. 1) Replace the EZ80, heck they are cheap, replace them both. 2) Does the wow and flutter remain? 3) If the wow and flutter go away, and if the problem(s) persist with the buzz and the knob go to 4. Trying to solve multiple problems at once is not a good idea. If the wow and flutter is still there, rediagnose or continue on with 4 and see if it changes the other aspects. 4) Move the amp to a different room, a different floor, power up, does it still buzz and does it change with the knob? 5) Ground the jacks. Connect the middle of the RCA jack to the outer jacket, just short it. That will put the input signal to ground. - Does the problem still occur? - Does the problem change with different input jacks selected on the front knob? I'm sorry to say, that unless you're proficient with working on tube amps, this problem may be beyond a solution for you as it will and/or may require opening up. You're dealing with high voltage and live AC. Do not do this unless you know what you're doing. You can die easily. Since you're in Pasadena, you may be able to find someone to help you out. You may want to follow up in the DIY section after you get the additional info, but I can't guarantee that.

The tubes I currently have it are:

RFT ECC82 x2
Sovtek 6C19 x2
Jan- Philips EGC 6922 x2

I also have
Tesla ECC88 x2
Electro-harmonix ECC82 x2
JJ Electronic ECC82 x2

I tried switching out the RFT ECC82s for the Electro-harmonix. The single channel flutter was still there. The constant hum was as well, maybe a little better, but not definitively.

I'm looking into getting the other tubes tested or replaced. Can anyone suggest a good place to get tubes and what is a reasonable price to pay for these tubes if you happen to know? Also, what brand? Finally, the ECC88, what can that be used for on this amp?

Anouk, I appreciate you're having a problem as well however I don't know that it is the same problem I'm trying to solve. Maybe we should keep the threads seperate so things don't get confusing on what is being addressed.