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Woo Audio Amp Owner Unite
Jun 17, 2012 at 6:40 AM Post #21,871 of 42,298
Firstly, left me apologize for a lengthy first post.
 
I have a question about a mains hum on a WA22. I'm new to WA22 ownership and this is my first valve amp so I'm not sure what to expect. For all I know all amps might be the same. I'm not the first owner of this amp and it's just over a year old. I have a mains hum that is independent of volume, which is noticeable when the music is quiet and very noticeable between tracks (amp sounds great up to that point!)
 
The facts:
  1. Amp running is on 240v 50Hz mains in the UK.
  2. I have tried different power sockets, a different location, running without an earth, running through a UPS.
  3. Hum is not affected by volume.
  4. Hum doesn't seem to be affected much by using different valves and swapping valves left to right (see list below).
  5. Hum still exists when there is no source connected (just power lead and the headphones).
  6. Hum is louder when on Hi impedance setting.
  7. During the start-up process, when the slow start protection circuit switches to full power the hum increases.
  8. The capacitors look OK, saying that I'm no expert, but don't seem to be bulging.
  9. The power lead is nothing special but I can't see that making any difference.
 
I have spoken to Jack @ Woo and he has kindly offered to have a look at the amp under warranty, with me paying for shipping. The bad news is shipping to and from the US is going to cost around £200 ($315). I don't want to go down that route if there's nothing wrong or there is something I can do here, so trying to exhaust all possibilities before resorting to sending back.
 
Any help or suggestions welcomed.
 
Thanks,
Neil.
 
Current Tubes:
Power:
  1. GEC 6080
  2. Sovtek 6AS7G
Driver:
  1. Zalytron 6SN7GTB
  2. RCA VT231 Smoke Glass
Rectifier:
  1. EML 5U4GM Mesh Plate
  2. Electron Tube 274B
 
Jun 17, 2012 at 7:33 AM Post #21,872 of 42,298
Quote:
redcarmoose said:

 
 
 
Not all else................................................
rolleyes.gif
Click to expand...

 
+1
 
beerchug.gif

 
Jun 17, 2012 at 3:25 PM Post #21,874 of 42,298
Quote:
idandelions said:
Firstly, left me apologize for a lengthy first post.
 
I have a question about a mains hum on a WA22. I'm new to WA22 ownership and this is my first valve amp so I'm not sure what to expect. For all I know all amps might be the same. I'm not the first owner of this amp and it's just over a year old. I have a mains hum that is independent of volume, which is noticeable when the music is quiet and very noticeable between tracks (amp sounds great up to that point!)
 
The facts:
  1. Amp running is on 240v 50Hz mains in the UK.
  2. I have tried different power sockets, a different location, running without an earth, running through a UPS.
  3. Hum is not affected by volume.
  4. Hum doesn't seem to be affected much by using different valves and swapping valves left to right (see list below).
  5. Hum still exists when there is no source connected (just power lead and the headphones).
  6. Hum is louder when on Hi impedance setting.
  7. During the start-up process, when the slow start protection circuit switches to full power the hum increases.
  8. The capacitors look OK, saying that I'm no expert, but don't seem to be bulging.
  9. The power lead is nothing special but I can't see that making any difference.
 
I have spoken to Jack @ Woo and he has kindly offered to have a look at the amp under warranty, with me paying for shipping. The bad news is shipping to and from the US is going to cost around £200 ($315). I don't want to go down that route if there's nothing wrong or there is something I can do here, so trying to exhaust all possibilities before resorting to sending back.
 
Any help or suggestions welcomed.
 
Thanks,
Neil.
 
Current Tubes:
Power:
  1. GEC 6080
  2. Sovtek 6AS7G
Driver:
  1. Zalytron 6SN7GTB
  2. RCA VT231 Smoke Glass
Rectifier:
  1. EML 5U4GM Mesh Plate
  2. Electron Tube 274B
Click to expand...

 
I had the exact same problem and same symptoms when I received my WA22. It was humming even without the power cord plugged in and no source plugged in, with just only headphone. I was trying to solve it for a week and came to the conclusion that the Center transformer on the WA22 for some reason is making up noise from my source. When i first got it I placed my WA22 on top of my DAC and it hummed then i placed them apart, to put it within a few inches of eachother, it still hummed but less. So then i unplugged everything and realized it was still humming without anything plugged in other than my HD800 whenever i turned on my DAC, so i tried to move the WA22 around and noticed whenever the center transformer is within 5 inches to the DAC it will pickup this humming noise. 
 
So try to move the WA22 at least 1 feet away from any electronic with a transformer. Hope that helps
 
Jun 17, 2012 at 6:08 PM Post #21,875 of 42,298
Nice answer fenom60. I hope that is the case and helps.

I was getting ready to ask about your avatar. I thought it was wild there were so many nice looking guitars in the row, but it didn't look to be a music store. Then I clicked on your profile. Only your monitor and its size gave away that they were small little desktop models. That was trippy lol.
 
Jun 17, 2012 at 6:16 PM Post #21,876 of 42,298
My wife just ordered me the Audiophilleo PurePower upgrade for my Audiophilleo 2. Should be sweet. I'm looking forward to checking it out. The only problem now is that I'll be going back to straight USB for the couple of weeks or so it will take them to mod my AP2 to be compatible with the PurePower power supply.

Here is a link if anyone is curious to check it out.
http://www.audiophilleo.com/purepower.aspx
 
Jun 17, 2012 at 6:32 PM Post #21,878 of 42,298
Quote:
fenom60 said:
 
I had the exact same problem and same symptoms when I received my WA22. It was humming even without the power cord plugged in and no source plugged in, with just only headphone. I was trying to solve it for a week and came to the conclusion that the Center transformer on the WA22 for some reason is making up noise from my source. When i first got it I placed my WA22 on top of my DAC and it hummed then i placed them apart, to put it within a few inches of eachother, it still hummed but less. So then i unplugged everything and realized it was still humming without anything plugged in other than my HD800 whenever i turned on my DAC, so i tried to move the WA22 around and noticed whenever the center transformer is within 5 inches to the DAC it will pickup this humming noise. 
 
So try to move the WA22 at least 1 feet away from any electronic with a transformer. Hope that helps
Click to expand...

 
Hi fenom60, I've looked at interference from other devices. I have even had the amp in a room on a wooden table, with no other equipment present other than the headphones and power lead, but the hum was still there :frowning2: 
 
This probably doesn't help, but, as soon as I switch off the amp the hum stops instantly whereas the music continues until the capacitors are drained and/or the valves cool down.
 
Jun 17, 2012 at 11:26 PM Post #21,879 of 42,298
Quote:
sid-fi said:
Nice answer fenom60. I hope that is the case and helps.
I was getting ready to ask about your avatar. I thought it was wild there were so many nice looking guitars in the row, but it didn't look to be a music store. Then I clicked on your profile. Only your monitor and its size gave away that they were small little desktop models. That was trippy lol.
Click to expand...

 
Haha the little guitars are collectible mini versions of the guitars of "hide"-( he day) from a legendary japanese rock band X- Japan. =D I used to own a real size of the yellow hearts guitar. 
 
Jun 17, 2012 at 11:36 PM Post #21,880 of 42,298
Quote:
idandelions said:
 
Hi fenom60, I've looked at interference from other devices. I have even had the amp in a room on a wooden table, with no other equipment present other than the headphones and power lead, but the hum was still there :frowning2: 
 
This probably doesn't help, but, as soon as I switch off the amp the hum stops instantly whereas the music continues until the capacitors are drained and/or the valves cool down.
Click to expand...

 
Hmm if it only hums when you turn on the WA22 then it might be your power tubes starting to go bad. My 7236 with probably 500 hours is humming much more noticeably than my new 6AS7G that i just started using. 
 
Jun 17, 2012 at 11:47 PM Post #21,881 of 42,298
The 7236 also has more gain than the 6AS7G, so that could possibly be part of it.
Quote:
fenom60 said:
 
Hmm if it only hums when you turn on the WA22 then it might be your power tubes starting to go bad. My 7236 with probably 500 hours is humming much more noticeably than my new 6AS7G that i just started using. 
Click to expand...

 
Jun 18, 2012 at 3:45 AM Post #21,882 of 42,298
Quote:
musicman59 said:
IMO if you want to upgrade tube go with a pair of 596, a pair of 6F8G (any brand) BG/RP and a nice pair of 300B. I am running right now EML 300B Mesh, Emerson (TungSol) 6F8G BG/RP and 596 and really love the sound.
Click to expand...


thanks for the tip. 
 
seems like i'm following you though...first rp010 and now wa5.  now i'm thinking re-cabling my t1 :wink:
 
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