[rental_magica]

Hi

I just want to see whether my amp is an exceptional one which have hum or it is a common for the WA5

 

[Spareribs]

Check your tubes. Change tubes to see if there is a difference. I recently bought the Ming Da amp and had hum noise but it was because of a defective tube. I replaced the tube and it was fine. Good luck brotha.

 

[Graphicism]

Just a thought... is your source turned up all the way? Turn the source to 100% and amp accordingly.

 

[rental_magica]

the things is that i still hear hum even though i disconnect the source.
right now the amp has around 50hr of playing. and the hum is still in the high output jack even though at zero volume

 

[vdub]

Try a decent power conditioner. I have a Furman unit and the noise floor is non-existent. Oh yeah, you need more burn in time, don't use cheap power cable, and make sure your connetions on the tubes are clean.

 

[rental_magica]

@vdub

i don't think i have a problem with my power line because i am using a very good power conditioner . I am using nordost valhalla and black sand statement one for the amp.

I got no hum from my previous past headphone amplifier.
the WA5 is really a very very excellent amp. I love it now but the hum noise for the high impedance jack annoying me a lot. Right now i can only listen to music with the low impedance jack.

 

[takezo]

you really should send it back to wooaudio for them to have a look at it. it's not
acceptable for a $3k+ amp to exhibit humming, especially when other owners of
the wa5 LE don't suffer from it. it's perplexing that all of your drive tubes could be
defective with a humming or noisy characteristic, but as the noise/hum is increasing
with your volume dial, it's being amplified. it's probably not a heater issue but maybe
something more simple like a bad solder or defective cap or resistor. good luck.

 

[Gvvt]

You didn't say if you've tried changing the tubes. You should probably check them before sending it back to Jack, at least to avoid having to pack it up unnecessarily...

 

[rental_magica]

Quote:

Originally Posted by Gvvt /img/forum/go_quote.gif You didn't say if you've tried changing the tubes. You should probably check them before sending it back to Jack, at least to avoid having to pack it up unnecessarily...

that's why i am asking people around and spending more time for burning in the amp and the tubes to see whether the problem will disappear or not

luckily, i can try another Woo WA5 at the end of next week. So i can use my own tubes, cable , source, and power conditioner on that Woo. If i get the same hum, then the hum might come from my tubes .

if not, then it is definitely the problem of the amp

I really don't want to send the amp back to Jack because it will cost a lot for shipment and wait time too.
I only need the amp has no hum for both low and high output jack at the volume below 12 o'clock(half of the volume). Right now i hear hum even at 0 volume for the high

 

[takezo]

considering we've previously narrowed it down to the drive tubes or amp itself, i'm
inclined to think it's the amp mainly because i can't imagine every one of your 6sn7
pair has a hum/noise issue. it's plausible... but just not probable.

have you allowed others to listen in? do they feel it's a 60hz low level hum or more close
to white noise? white noise and such are tube issue related to rf interference but the
hum is another issue that can be addressed by a technician. have you tried changing
out the power cord or using a ground cheater plug? cheater plugs are available at most
hardware stores for 35 cents. keep us informed please.

 

[Rob N]

When you adjust the hum pots does the hum level
actually alter?

 

[rental_magica]

Quote:

Originally Posted by Rob N /img/forum/go_quote.gif When you adjust the hum pots does the hum level actually alter?

For Low output jack, it is dead quiet below 11 o'clock. Above it , hum appears and will become louder as the volume increase

For High output jack, small hum at zero volume and stays constant to around 10o'clock. Above that, it will become louder according to the level of volume

 

[rental_magica]

@takezo

i have already tried to use different power cord for the Woo(black sand statement one, black sand violet zII, and nordost horus valhalla). The woo's sound changes if i use different power cord. And i like it a lot because i am also a cable greek.
However, I get the same hum noise for all of them

 

[mikeymad]

I have the WA5 not LE... But no hum at all on my end.

At Max vol I will get some noise (It still is a tube amp), but it is not hum.

Cheers,

 

[takezo]

Quote:

Originally Posted by rental_magica /img/forum/go_quote.gif @takezo i have already tried to use different power cord for the Woo(black sand statement one, black sand violet zII, and nordost horus valhalla). The woo's sound changes if i use different power cord. And i like it a lot because i am also a cable greek. However, I get the same hum noise for all of them

yes, i hear subtle differences when i changed power cords too. i don't think it's
adding to the sound, but more perhaps different cords allow differing amount
and quality of current to pass through, clean or not.

anyway, i don't think it's the power tube nor the rectifiers since you last tested
the amp without the drive tubes in it. i think we've isolated the hum to be
coming from the drive tubes or anything directly connected to it, like the
heater filament connection, cathode bias caps/resistors or the socket itself...