[cddc]

My guess is that some gas leaked into the NOS tube and caused humming issues, after running tube 24 hours, heat activated the getter which absorbed the leaked in gas, and tube was back to good.

 

[cddc]

Interesting... 7236 has a higher output, I could be wrong

You are right, 7236 has higher gain than 6080/6AS7G does.

 

[JKDJedi]

Ya, one way or the other it seems power tubes output is making a small difference in when the distortion happens. I don’t know enough to ascertain what that means, so I’ll just troubleshoot a bit.

oh, and can you see the super ghetto black tape over the blue power light?

LMAO... Same with my amp... black taped the same.

 

[toufeeq]

I'm running the DV336SE with a pair of vintage Tung-Sols(TS 6SN7GTB and the TS 5998 JAN-CTL-5998) and I seem to be getting a hum/buzz in both channels. Both of these tubes were purchased from Ebay and marked as NOS. The hum/buzz is constant and doesn't change in loudness if I increase/decrease the volume and its uniform across both channels.

At first, I thought it was the 6SN7 based on this 72 hr burn-in thread. But then I swapped the Tung-sol for the stock 6SN7 and I still get the same hum/buzz which leads me to think its not the 6SN7. Any idea what might be happening?

 

[Xibipiio]

I'm running the DV336SE with a pair of vintage Tung-Sols(TS 6SN7GTB and the TS 5998 JAN-CTL-5998) and I seem to be getting a hum/buzz in both channels. Both of these tubes were purchased from Ebay and marked as NOS. The hum/buzz is constant and doesn't change in loudness if I increase/decrease the volume and its uniform across both channels.

At first, I thought it was the 6SN7 based on this 72 hr burn-in thread. But then I swapped the Tung-sol for the stock 6SN7 and I still get the same hum/buzz which leads me to think its not the 6SN7. Any idea what might be happening?

Are the tubes well seated in their sockets? You might try cleaning the pins to your tubes with isopropyl alcohol (no scent or additives) and letting them dry. Also, you could gently clean your tube sockets with pipe cleaners. Let everything dry well and check for lint, etc.

I’ve found if the tubes will hum if they’re not fully in the sockets.

 

[JKDJedi]

Are the tubes well seated in their sockets? You might try cleaning the pins to your tubes with isopropyl alcohol (no scent or additives) and letting them dry. Also, you could gently clean your tube sockets with pipe cleaners. Let everything dry well and check for lint, etc.

I’ve found if the tubes will hum if they’re not fully in the sockets.

I second this, and if the amp is new I'd suspect it needs a good burn in as well, maybe leaving everything on for a few days.

 

[Gallic Dweller]

I can't believe that the hum issue is still alive and kicking - go back near the beginning of this long thread and see the real reason, it's a design and component problem. Also so many of you don't mind that there is only one minute sweet spot - that too is easily solved.

 

[JKDJedi]

I can't believe that the hum issue is still alive and kicking - go back near the beginning of this long thread and see the real reason, it's a design and component problem. Also so many of you don't mind that there is only one minute sweet spot - that too is easily solved.

One minute sweet spot? And yes, new owners will be just as puzzled as we were when we first got this unit so yes, it's still alive in 2019.

 

[toufeeq]

Are the tubes well seated in their sockets? You might try cleaning the pins to your tubes with isopropyl alcohol (no scent or additives) and letting them dry. Also, you could gently clean your tube sockets with pipe cleaners. Let everything dry well and check for lint, etc.

I’ve found if the tubes will hum if they’re not fully in the sockets.

I think so. I tried moving them around and there is no give on either tubes. I will try the cleaning method you suggested. Thanks.

 

[toufeeq]

I second this, and if the amp is new I'd suspect it needs a good burn in as well, maybe leaving everything on for a few days.

The amp was purchased Dec'17 and I ran it on the stock tubes for the longest time. Only now getting to try different tubes.

 

[DenverW]

I have trouble believing that there is a one minute fix that will cover every darkvoice 336se amp, every tube, and every tube combination. The hum issue is still a viable topic. Are you referring to the internal fix that requires soldering?

 

[toufeeq]

Are the tubes well seated in their sockets? You might try cleaning the pins to your tubes with isopropyl alcohol (no scent or additives) and letting them dry. Also, you could gently clean your tube sockets with pipe cleaners. Let everything dry well and check for lint, etc.

I’ve found if the tubes will hum if they’re not fully in the sockets.

OK, that seemed to have helped. I took the power tube out and cleaned the connectors with a cloth(no alcohol) and it seems to be better now. Thank you. The TS5998 isn't exaclty a tight fit in the socket so maybe it just needed to be re-inserted.

 

[toufeeq]

OK, that seemed to have helped. I took the power tube out and cleaned the connectors with a cloth(no alcohol) and it seems to be better now. Thank you. The TS5998 isn't exaclty a tight fit in the socket so maybe it just needed to be re-inserted.

Nevermind, it returned after 5 minutes. So on power on and while it is warming up, there is no hum. The hum sets in after 5-10 minutes of use.

 

[JKDJedi]

Nevermind, it returned after 5 minutes. So on power on and while it is warming up, there is no hum. The hum sets in after 5-10 minutes of use.

Try plugging it into a different outlet by itself, no power strips

 

[JKDJedi]

Nevermind, it returned after 5 minutes. So on power on and while it is warming up, there is no hum. The hum sets in after 5-10 minutes of use.

You could send that 5998 to me for further evaluation.. (and letting it bake for another 72 hours might help, if not you might have a bad tube) ;(