Bottlehead Forum
General Category => General Discussion => Topic started by: maheeinfy on December 23, 2015, 11:26:21 AM
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My question is not about a BH amp, but I am posting here looking for some help. Pls bear with me, I m new to this forum and tube amps.
I recently got a Wooaudio WA2 amp, new from wooaudio, and i am using it with Beyer T1 and few other cans.
It does hum through the headphones when volume is at 11' clock and hum only becomes louder from there.
i did some testing to isolate the device in the chain that is causing this problem. I found that when nothing is connected to amp(except power), there is no hum.
However when i connect a DAC, there is hum thru headphones. Even with DAC turned off, there is hum(i tried output of Schiit Modi, Emotiva DC1, line out of Fiio X3ii - each of them powered off and not even connected to my laptop). RCA cables i am using are from Schiit and Emotiva, so i think they are good quality.
I tried different power cable, wall sockets, even took the amp to friend's apartment for testing, and the result has been same.
I have been using Schiit Magni, JDS O2, few speaker amps from Emotiva for more than a year - none of them have any hum issues.
I contacted Wooaudio and was told to upgrade cables, dac to resolve the hum problem. But I think the cables, dac are not the reason.
On other note, one of the 6080 tubes i received, i think is faulty. It gives out hiss on one of the cups on headphone, even at zero volume. When i switch 6080 tubes on the amp from left to right, hiss also switches on headphones
My question - What could be the reason for this dreaded hum? i'd appreciate any help in resolving this. This is my first tube amp, and i havn't been able to enjoy it due to all these problems.
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No idea about Woo amps but you could try wrapping/twisting your rca input cables round each other and see if it has any effect on the hum.
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No idea about Woo amps but you could try wrapping/twisting your rca input cables round each other and see if it has any effect on the hum.
Thanks i will try that.
I just tried this...I removed all the input RCA connections from the amp. Then connected the left and right input of the amp with a single RCA cable(i think the apt word is 'shorted'). With this, there is no hum.
I don't know what that means, but thought i ll put it out there
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It does hum through the headphones when volume is at 11' clock and hum only becomes louder from there.
What's 11 o'clock? Is that all the way up? 1/8 of the way up????
i did some testing to isolate the device in the chain that is causing this problem. I found that when nothing is connected to amp(except power), there is no hum.
Then the amp is working fine.
However when i connect a DAC, there is hum thru headphones. Even with DAC turned off, there is hum(i tried output of Schiit Modi, Emotiva DC1, line out of Fiio X3ii - each of them powered off and not even connected to my laptop). RCA cables i am using are from Schiit and Emotiva, so i think they are good quality.
This sounds like a grounding issue. Woo should be able to help you with this.
On other note, one of the 6080 tubes i received, i think is faulty. It gives out hiss on one of the cups on headphone, even at zero volume. When i switch 6080 tubes on the amp from left to right, hiss also switches on headphones
If this isn't intrusive with music playing, I wouldn't worry about it.
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Sounds like you have a ground loop. I would contact the manufacturer and ask them specifically if they have any suggestions for resolving ground loop issues. You might get a little more info from them on how to deal with the issue if you present them with that additional info.
This kind of thing puts us in a difficult position. We do our best to help our own customers. Presumably because of that people will tend to come to us to ask for help about non-Bottlehead products. The problem is that if we answer we will be viewed by some as denigrating the competition's product, though that is not our intention.