Hi I am hearing unusual whining/mechanica/airy noise from left channel and only in my room.
I tried the amp different room no noise, also I moved the amp the noise increase/decrease.
why is it only in my room? How can I eliminate this noise?
I tried the amp different room no noise, also I moved the amp the noise increase/decrease.
why is it only in my room? How can I eliminate this noise?
Lamp dimmers, LED lights and fluorescent lights would be my next guess. Anything with a cheap switching power supply.
This is the fourth thread about your Woo Audio WA2 making noises (humming, buzzing, sounding metallic, and whining/mechanica/airy noise).
In your first thread of February this year the first commenter advised you to bring it back to the vendor. Maybe it's not too late for that.
In your first thread of February this year the first commenter advised you to bring it back to the vendor. Maybe it's not too late for that.
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Do you have a Xmas tree in the room with Xmas tree lights on by any chance? Mine interfere with my valve amp, I'll fit an RFI LP filter on the IP, something like a 1k and 470p to roll off everything over 100khz. Best bet is to try and drag your scope into the room and scope the amp IP and OP. Failing that record the amp OP with Audacity and analyse the recording with the spectrum analyser software.
Another thing you could try, find a bit of exposed metal of the amp that is grounded/earthed, get a jumper lead with croc clips, clip one end to said ground, the other end to a sheet of metal or at a push a tin foil covered bit of card, move the sheet around, in front of the IP RCA's and voltage amplification stage; any difference?
Andy.
Another thing you could try, find a bit of exposed metal of the amp that is grounded/earthed, get a jumper lead with croc clips, clip one end to said ground, the other end to a sheet of metal or at a push a tin foil covered bit of card, move the sheet around, in front of the IP RCA's and voltage amplification stage; any difference?
Andy.
Do you measure continuity (few ohms at most) between the power plug safety ground terminal and the WA2 metal chassis? And between the ground input RCA input and the chassis? If the chassis is floating, you may try to connect it to ground. The electrical interference may also enter trough the unshielded input tubes (it may then change sligtly when you put your hands near the tubes). If you have spares, you may try to replace the input tubes.
Since it is Christmas, the title reminds me of an Australian joke ... (I'm a Pommie by the way!)
Q. How do you know when a plane load of Pommies have arrived at Sydney Airport?
A. The whining doesn't stop when they turn the engines off.
Q. How do you know when a plane load of Pommies have arrived at Sydney Airport?
A. The whining doesn't stop when they turn the engines off.
Sorry for late response I had cold and still have it.
I dont have any Xmas Tree in my room but outside my house there are tree lights! and even after Christmas there are other lights/street lights.
Can you recommend any good Rfi Filter that I can use for OTL amps?
I'm not really familiar with scopes but ill borrow from someone and play around with it.
The Amp works fine when I leave it on top of my bookshelf next to side wall, but I wanna put it on my work desk sometimes too.
Yes I measured continuity from the power gnd to every metal parts and also to the input gnd and its zero ohm!
You are right when I put my hands next to the tubes the noise reduces slightly, but I tried with other tube but makes no difference.
If you move the amplifier closer to any of these does the noise change? Is it perhaps related to these devices?
Regards, Gerrit
Regards, Gerrit
Try a 1k - 2k2 and a 470p on the IP, these will block/attenuate any signal from around 100khz getting into the signal path. Another way RFI interference can get into your amp is through the speaker wires. See this thread here - https://www.vintage-radio.net/forum/showthread.php?t=186966