BAT VK75SE buzz and humming ?? help..

Hello all, received a BAT VK-75SE which by the way is a lovely Tube amp for those that are not aware.

Unfortunatly I have plugged it in and have had a constant buzz since day one.. the buzzing remains even when Interconnects are removed and ground is lifted

I have :

1. Plugged the amp in a different part of the house- No Change

2. Changed Speakers and speaker cable - No Change
3. Changed PowerCord and Lifted ground - No Change

The amp itself is dead quiet, no transformer hum or anything.. could tubes do this ? ..

thanks all in advance !

Sounds like bad tubes.
Does this buzz come from one channel only?
If it does try to exchange left and right channel tube one-by-one to identify bad one.
In any case call BAT – they are usually very helpful.
You can test your amp by light touching of chassis arround the input tubes with screwdriver and hear if buzz increases or you hear pops. You can also bring close light bulb. Normally BAT units will not react on light bulb brought close to amplifier but if there is a bad tube they will oscillate. That will definitely indicate that tubes need to be replaced not neccessarily input ones but any of existing.
If it won't help you'd have to get in touch with BAT and probably send your unit for service.
how loud is the buzz, on my 75se I have it, but much past 2-3 feet away I can't hear it....low level...

I'd call what you find out please. Thanks
I had a "hum" problem a long long time ago. Victor troubleshot the problem in one call. Call Victor.

Victor has been trouble shooting it for a week, asking me to jumper the amp's inputs.. I did with no success, I jumper'ed all three pins and only pin 2/3

No success, have not heard back after my last email..maybe he is on vacation.

Anyway, is on both sides of the amps, meaning both speakers are buzzing equally.

Jfrech: I also hear it about 4ft away .. still, I don't think that this is normal...I maybe wrong, if it is, I bought the wrong amp.
What tubes and how old is the amp?
I assume that VK75 is not a long time in production to undergo capacitor replacements for instance. The fact is that if it "eats" tubes especially one earlier than others than definitely something is wrong.
You may want to check bias if possible. Tube oscilates when it doesn't have negative-enough grid voltage. Check an output tube manual for allowed negative voltage tolerance or call Viktor to find out and measure between the ground binding post and pin#5 with amp on and no tubes using voltmeter set to measure low-hundreds of volts.
Marakanetz, thanks... have no idea what you said.. but I presume I need to test the tubes out one way or another ..

I may have a guy locally that can do this..

The unit is not old, I would say within 2-3 yr.. the TUBES, well the box that they were wrapped in said "CCCP" need I say more..

Are you using XLR adapters on the inputs? There have been incidences where the adapters are the cause of the hum. Try using a pair of balanced interconnects, See if that helps.
you didn't buy the wrong amp...that's one of the best. somethings up...bad tube, bad component...ground loop...
I'm sure you have checked the fuses. Every time
I had a fuse go I would hear an increase level
of hum.
would this thing be working if it had a blown fuse... where should I be looking.. I do recall having extra fuses in the box..


AA Capitole plain isn't compatible with some amplifiers when using balanced Interconnects because of a "pin 1 problem"which can cause a line level signal ground loop. See my thread regarding impedance mismatch for more information. Could be your problem
Hey Mejames, I have heard that, but there is no issue with that as far as I can see.. the buzzing still happens when the components are unplugged

If a output tube fuse is blown, it will work, and it will increase the hum considerably. Also a channel should have less power-like 1/2. If one in each channel is blown, it will still have balanced sound-but with lot's of noise and basically sound like sh&%. Look at the output tubes. Are the 4 led's on and green? If one is off, then you have one output tube fuse blown. If one is red, then a problem with the auto bias circuit (more likely a bad tube). I have had some issues with bad output tubes...replace one about every 6-12 months. No big deal though.

To replace a output tube fuse, UNPLUG the amp from ac, turn it over, and you'll see the fuse holders underneath.
Thanks ..

all LEDs are Green and functining.. but I will check the fuses anyway..

Wow.. tubes are work ..hehehe
the Ghost of the Buzzing Halcro's has come back to haunt you.

but seriously, maybe try moving the amps to another room with your surround speakers and Capitole and see if that eliminates the may have some sort of RF that is being recieved by the amps in that room......or try the amps in someone else's system.

try removing the Panamax from the system temporarily.....there may be a conflict someplace.

just a few thoughts from a clueless one......
Hi Mike... no kidding... Im cursed !!!

I have a Hydra and plugged the unit with the CAP in another room with an extention cord, never physically moved the 100lb amp ...but will try !

Ok, moved the AMP to a different room..checked ALL fuses..all looks great ...sounds to me like the amp has a problem !

thanks folks !

Matt, I have the same amp. I use a balanced isolation power transformer for all my power (Equitech).
I have to put my ear near the speaker to hear a hum.
I'm sure Victor will be able to help you out. The amp is wonderful sounding. Hope you get this resolved.