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WA3 High pitch whine

post #1 of 20
Thread Starter 

Hi All,

 

I have a WA3, and it has started making a high pitch whine. It is audible without the headphones on, very very high frequency (if I wasn't in my 20s I wouldn't hear it). A similar frequency noise happens in the headphones too, on and off.

 

Changed the tubes, still the same. At first I thought it was the tubes because if I lightly tap the 6080 tube (a 5998) it stops, but then comes back. Moving the volume knob doesn't affect the annoying noise, music masks it but it comes through in the silence at constant volume regardless of volume knob position.

 

It is quite intermittent but noticed it getting more frequent.

 

Any ideas? I can put up with it, but would rather not :P

 

Cheers!

post #2 of 20
Thread Starter 

It should also be noted that a short time ago, I got a dodgy 5998 tube that killed the preamp pair too. Hopefully it didn't cause amp damage?

post #3 of 20

I would send it back for repair. tube failures can cause amps to do very weird things. 

post #4 of 20
Thread Starter 

Awwww don't say that! Im in the UK and shipping a Woo will be expensive :(
 

Quote:
Originally Posted by nikongod View Post

I would send it back for repair. tube failures can cause amps to do very weird things. 



 

post #5 of 20

so its the actual amp making the noise not the headphones?

 

because i've had whine or hum before but was always a microphonic tube.

 

was the 5998 a tung sol? was there anything visibly wrong with it?

post #6 of 20
Thread Starter 

Well a TS 5998 was faulty and took out the preamps (http://www.head-fi.org/forum/newestpost/580413) the 5998 had a rotating base ... that went in the bin along with the damaged preamps.

 

I then tried another TS 5998 and a pair of Brimar CV2492s, which had the noise ... then I swapped them out for yet another 5998 and another set of Brimar CV2492 . Same noise. The noise seemed to be coming from the amp itself and through the headphones ... though I am trying to eliminate local interference from power-saving bulbs, my computer screens (the amp is on the desk with me).

 

Then I popped in a 6AS7G with non-Brimar preamps and that seems to have now cured it ... so maybe it was the combo of the TS 5998 and the Brimars? (seeing as I tried 2 unique sets of that combination) ... Which would be a crying shame because apart from the whine, they were lovely together ...

 

Im gonna run it for a while, see if it comes back.

 


 

Quote:
Originally Posted by Rawrbington View Post

so its the actual amp making the noise not the headphones?

 

because i've had whine or hum before but was always a microphonic tube.

 

was the 5998 a tung sol? was there anything visibly wrong with it?



 


Edited by volted - 12/4/11 at 12:52pm
post #7 of 20

hmm.

i hope it works out.  let us know how it goes.

 

i think sometimes tubes can just be strange beasts.  but they sure do sound nice

post #8 of 20

I know this is an old thread, however I have the exact same problem as the original poster. The noise doesn't happen straight away, it kicks in once the tubes have warmed up.

 

I have a WA3 with the following tubes plugged in:

1 x 6080WC GE JAN NOS

2 x 6DJ8 Phillips ECG JAN NOS

 

These are the tubes that came with my amp.

 

I am using a ground loop isolator and everything is connected to the same Belkin RFI/EMI filtering power board. I switched the position of the 6DJ8 tubes, made no difference. I put in some 7308 Amperex vintage gold pin drivers, made no difference. I reseated the 6080 power tube, made no difference.

 

I hear an intermittent variable pitch squeal / static noise that does not alter with volume - all the way down through to all the way up, I hear the same noise. Its silent about 80% of the time, then a weird scratching/buzzing/squeal will kick in for anything from one to many seconds, then eventually cut out. Its mostly in the left ear, but sometimes the right. Its a bit like those old modem sounds in terms of how often it changes pitch - sometimes a long lower pitch squeal, sometimes a higher pitch. Sometimes I think I can hear both at once, or at least in quick succession.

 

I had a bit of a breakthrough today when I started listening to the tubes directly with a mechanical stethoscope. The WA3 itself is what is making the noise. Or more specifically, when I put the stethoscope on the 6080 tube, it sounds like the noises are coming directly from the 6080 tube. I can hear the noise in the other tubes, but its much more faint, like they are picking the noise up from the 6080.

 

 

I can now actually hear the amp making the noise directly with nothing else at all connected and everything else powered down.

 

I have ordered two more power tubes of different kinds, hopefully that solves it.

 

1x 7236 Sylvania NOS 1963

1x 6AS7G RCA NOS 1951

 

Don't really want to send it back, it sounds awesome despite the annoying noises.

 

I am curious whether the OP ever solved the issue, or whether anyone else had similar issues. If it is the power tube as I suspect, then surely others have have experienced this kind of thing at some point...

 

For bonus points - does anyone know why/how the power tube in the WA3 can power left and right separately in the same tube? Just curious based on the noise coming primarily from the left... is it still possible that the output/power tube could be the cause?


Edited by ctrlshift - 4/26/14 at 4:17am
post #9 of 20
It sounds like a combination of microphonics (which are audible outside the tube from the amp sometimes) and a noisy tube. This can happen in any of the three tubes and is common. The audible one is almost always the power tube (big one) and the fizzy sound almost always the drivers. Sometimes a sharp rap with the end of a pencil (don't break the tube) shuts them up for a while...don't do this to expensive tubes unless you're shure they are ready for the junk bin. 6AS7 and all the related comparable types are known to be noisy...it may take a few to find a good quiet one. Each tube has two triodes in it, which is why the big one can do both channels. The small drivers are used differently and the left one is left and right one right.
Of the 6080, the WA or JAN CTL and TungSol / Chatham ones with metal mica holders seem to be quieter than most: http://www.ebay.com/itm/One-1959-Chatham-JAN-CAHG-6080-tube-Black-Plates-Top-Getters-/360904734840?pt=Vintage_Electronics_R2&hash=item5407993878
http://www.ebay.com/itm/6080WA-vacuum-tube-/251488095946?pt=Vintage_Electronics_R2&hash=item3a8ddbceca
Edited by GrindingThud - 4/26/14 at 5:14am
post #10 of 20
Thread Starter 

OP here, I solved the issue by basically finding tubes that dont whine. Went through about 4 5998s and a couple of sets of Mullard cv2492 before I found a set that don't whine. A tap with a pencil or whatever does help though. I'm putting it down to the oddities of tube amplification.

 

Total PITA though.

post #11 of 20
Thread Starter 

Best luck I had was with TS 7236, but I prefer the TS 5998s so ....

What you describe though, a volume independent high-frequency sound that sometimes oscillates is what I have. Audable though both the signal to the headphones and externally.


Edited by volted - 4/28/14 at 2:50am
post #12 of 20

Two new tubes arrived today:

 

1x 7236 Sylvania NOS 1963

1x 6AS7G RCA NOS 1951

 

They sound quite different from each other and from the stock tube. Both make noises, but more of a faint rustling leaves noise which I can tolerate. I haven't yet found a predictable pattern of issues so I have decided to stop looking for them so hard. The 6AS7G was insanely microphonic + ruslting leaves noises last time I plugged it in, but this time its completely fine. I didn't think I could forgive these little noises but I am starting to think its not such a big deal. To paraphrase a Jack Woo quote I read on this forum a few times - if you can't hear it when music is playing then who cares.

post #13 of 20

I have the WA3.  I've just relegated the fact it's a noisy amp.  I've tried many, many different tubes, different outlets, different parts of the city, different power conditioners, and the noise is always there.  You can't hear it while the music is playing, so I don't lose too much sleep over it.  But, it's there and I know about it, so sometimes I obsess over it.  When I emailed Woo about it, their standard response was "If you can't hear it while music is playing, it's of no consequence."  While that may be true, it put me off a little bit and I'm less inclined to buy another Woo amp again.

post #14 of 20
Thread Starter 

Problem is, I can hear noise when music isn't playing and when the heaphones are not even on my head!

post #15 of 20

I'm not convinced the power transformer in the amp is very good.  Depending on which tube I put in the power slot, the transformer will change different temperatures and hum at different volumes.  Tightening the restraining bolt down did help a little with the hum.

 

These amps are quite simple.  The only active components in them are the tubes and the transformer.  Noises have to be coming from one of them.

 

Since it uses a toroidal transformer, you might have some DC in your power line.  Toroidal transfomers hate that.

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