[JackarlTwo]

I recently got my H5KPCU and I don't have that switch. Unfortunately I also suffer from noise. It's a 50 Hz hum and I tried different cables/ outlets with no other devices connected. There's less noise from one outlet but still audible. I also noticed that after a few hours the hum almost disappeared only to come back again. Could this be a matter of burn-in? But it seems pretty constant. The hum varies slightly from low to high volume and touching the top plate reduces the hum somewhat but not completely. So I'm thinking a ground-loop issue? I'm talking with Wieslaw to see if we can figure it out.

As far as sound goes I'm loving it! Atrium and HD650 is sounding better than ever, and this is with stock tubes and no burn-in. I was worried it'd be too warm for Atrium but I don't find that to be the case at all. The midrange is fantastic, the bass is punchy and deep, the treble is smooth yet detailed. A full bodied sound that isn't overly warm. The Burson amp sounds thin and brighter/ neutral in direct comparison with a smaller soundstage.

Now on to fix this annoying hum.

Edit: I just tried the amp in the kitchen outlet which is grounded and there's zero hum. Dead silent. The house is old and most wall outlets are ungrounded.

 

[alxw0w]

I recently got my H5KPCU and I don't have that switch. Unfortunately I also suffer from noise. It's a 50 Hz hum and I tried different cables/ outlets with no other devices connected. There's less noise from one outlet but still audible. I also noticed that after a few hours the hum almost disappeared only to come back again. Could this be a matter of burn-in? But it seems pretty constant. The hum varies slightly from low to high volume and touching the top plate reduces the hum somewhat but not completely. So I'm thinking a ground-loop issue? I'm talking with Wieslaw to see if we can figure it out.

As far as sound goes I'm loving it! Atrium and HD650 is sounding better than ever, and this is with stock tubes and no burn-in. I was worried it'd be too warm for Atrium but I don't find that to be the case at all. The midrange is fantastic, the bass is punchy and deep, the treble is smooth yet detailed. A full bodied sound that isn't overly warm. The Burson amp sounds thin and brighter/ neutral in direct comparison with a smaller soundstage.

Now on to fix this annoying hum.

Edit: I just tried the amp in the kitchen outlet which is grounded and there's zero hum. Dead silent. The house is old and most wall outlets are ungrounded.

It seems like you are suffering from ground loop.
What dac are you using? And how it's connected to your source?
Oops sorry somehow I missed that you already found the solution

 

[Warsoul]

I recently got my H5KPCU and I don't have that switch. Unfortunately I also suffer from noise. It's a 50 Hz hum and I tried different cables/ outlets with no other devices connected. There's less noise from one outlet but still audible. I also noticed that after a few hours the hum almost disappeared only to come back again. Could this be a matter of burn-in? But it seems pretty constant. The hum varies slightly from low to high volume and touching the top plate reduces the hum somewhat but not completely. So I'm thinking a ground-loop issue? I'm talking with Wieslaw to see if we can figure it out.

As far as sound goes I'm loving it! Atrium and HD650 is sounding better than ever, and this is with stock tubes and no burn-in. I was worried it'd be too warm for Atrium but I don't find that to be the case at all. The midrange is fantastic, the bass is punchy and deep, the treble is smooth yet detailed. A full bodied sound that isn't overly warm. The Burson amp sounds thin and brighter/ neutral in direct comparison with a smaller soundstage.

Now on to fix this annoying hum.

Edit: I just tried the amp in the kitchen outlet which is grounded and there's zero hum. Dead silent. The house is old and most wall outlets are ungrounded.

Sorry, can you take a clear picture of the bottom of the power tube?

 

[Warsoul]

Is that a 6V driver tube? Sure looks like a 6V heater getting 12V. Very bright!

I don't know the orientation of the 6/12V heater switch. In cases of heater uncertainty, the best approach is to use a 12V tube (12SN7). Either the 12V tube gets 12V and everything is fine. Or the 12V heater gets 6V and it sounds off, but doesn't damage the tube as quickly as a 6V tube getting 12V on the heaters.

Yes it was the wrong switch.
The amp works well with most of my headphones but distorts a lot the bass of my DT880 600 ohm. Could the wrong voltage have damaged the power tube?

 

[Bling527]

I don’t know, my H5 doesn’t have that switch. Surely if you ask Wieslaw he will get back to you soon!

i have a switch on my H5M. But it was a gain switch that I requested.

 

[roderickvd]

Was that switch not positioned lower on the plate also? More towards the headphone outputs?

 

[JackarlTwo]

Sorry, can you take a clear picture of the bottom of the power tube?

Sure. Best I can do with this crappy camera

 

[JackarlTwo]

Update about the hum: So I was still able to get a significant amount of right channel hum in the grounded outlet (no input signal, only power) after warmup. I had a spare 6N13S power tube and now all hum seems to be gone. I hope it was just a bad tube! I don't wanna celebrate too early. I probably should've changed tubes before trying a million outlets haha

 

[xanatizer]

I recently got my H5KPCU and I don't have that switch. Unfortunately I also suffer from noise. It's a 50 Hz hum and I tried different cables/ outlets with no other devices connected. There's less noise from one outlet but still audible. I also noticed that after a few hours the hum almost disappeared only to come back again. Could this be a matter of burn-in? But it seems pretty constant. The hum varies slightly from low to high volume and touching the top plate reduces the hum somewhat but not completely. So I'm thinking a ground-loop issue? I'm talking with Wieslaw to see if we can figure it out.

As far as sound goes I'm loving it! Atrium and HD650 is sounding better than ever, and this is with stock tubes and no burn-in. I was worried it'd be too warm for Atrium but I don't find that to be the case at all. The midrange is fantastic, the bass is punchy and deep, the treble is smooth yet detailed. A full bodied sound that isn't overly warm. The Burson amp sounds thin and brighter/ neutral in direct comparison with a smaller soundstage.

Now on to fix this annoyin

Update about the hum: So I was still able to get a significant amount of right channel hum in the grounded outlet (no input signal, only power) after warmup. I had a spare 6N13S power tube and now all hum seems to be gone. I hope it was just a bad tube! I don't wanna celebrate too early. I probably should've changed tubes before trying a million outlets haha

You're lucky. I didn't have any spares when my amp had a problem and I had to order them from Ukraine and wait a month. Didn't fix it.

 

[LobalWarming]

Yes it was the wrong switch.
The amp works well with most of my headphones but distorts a lot the bass of my DT880 600 ohm. Could the wrong voltage have damaged the power tube?

Not likely to have hurt the output tube. The driver tube, however, could have a very short life.

 

[Warsoul]

Sure. Best I can do with this crappy camera

Sorry man, my fault, I meant the top of the tube If you could, it would help me to understand if I messed up the tube or not

 

[JackarlTwo]

Sorry man, my fault, I meant the top of the tube If you could, it would help me to understand if I messed up the tube or not

I'm not sure what you could tell from it. I have 2 pairs and they all look identical.

 

[JackarlTwo]

Been going for 8 hours now. No hum. Just a great tone!

 

[JackarlTwo]

Nobody ever talks about this Bonus Eufonika perk: 10kg of free bubble wrap.

Great packaging cannot be overestimated.

 

[Joshjns]

Nobody ever talks about this Bonus Eufonika perk: 10kg of free bubble wrap.

Great packaging cannot be overestimated.

I still have some left, been using it for 2 years shipping things I sell!