[CJG888]

I would check and clean all connections (especially tube pins). Do you have a spare set of tubes so that you can eliminate a bad tube?

Other potential causes could be grounding issues (something which always seems to plague my systems) or a capacitor which is starting to fail…

 

[ProAcTivo]

The TA-26 is making the mechanical humming sound? You have some DC component on the AC line, try a DC Blocker in front of the TA-26 AC line to block that DC. It could also be a mismatch of the locale AC and the TA-26 build. What is your locale AC volts/hz? What is the TA-26 say on the back/label/model info you bought?

Not shure what a DC blocker is..but i will look into it. About the AC volts is all good..220V. I left the amp turned on all morning without tubes. Then i cleaned all the tube pins, and now i have very residual hum..not like before. Lets hope it still like this. If not i will report back.

 

[ProAcTivo]

I would check and clean all connections (especially tube pins). Do you have a spare set of tubes so that you can eliminate a bad tube?

Other potential causes could be grounding issues (something which always seems to plague my systems) or a capacitor which is starting to fail…

Thank you. I did that. I cleaned all pins and now i have very minimal hum.. lets see. Thank you

 

[ColSaulTigh]

DC blocker: https://avahifi.com/collections/used-demo-and-quick-ship/products/humdinger-dc-line-blocker

 

[ProAcTivo]

DC blocker: https://avahifi.com/collections/used-demo-and-quick-ship/products/humdinger-dc-line-blocker

Thank you. Well i guess the DC Blcker is not for me. It says it will not remove the hum coming out of speakers.. thats my case..its coming out of the headphones. The amp itself makes a little it of noise when turned on (just a bit) but the hum is coming from the headphones(left channel mostly).

 

[ColSaulTigh]

Thank you. Well i guess the DC Blcker is not for me. It says it will not remove the hum coming out of speakers.. thats my case..its coming out of the headphones. The amp itself makes a little it of noise when turned on (just a bit) but the hum is coming from the headphones(left channel mostly).

Disconnect everything from the amp and see if it goes away. If it still hums, unplug it and move it to the other side of the house and see if the hum remains. If so, it's more likely a tube causing it. If it goes away, you've got an impedance mismatch somewhere. Start adding components one at a time until you find it.

 

[ProAcTivo]

Disconnect everything from the shop and see if it goes away. If it still hums, unplug it and move it to the other side of the house and see if the hum remains. If so, it's more likely a tube causing it. If it goes away, you've got an impedance mismatch somewhere. Start adding components one at a time until you find it.

Ok. Will do that. I think is the Tung-Sol 6SN7GTB (Old made in USA). When i had the Tung-Sol 6SN7GTB new (Russia) i dont recall having the hum. For now is quiter but if the hum comes back i will try this.

 

[Ufanco]

Ok. Will do that. I think is the Tung-Sol 6SN7GTB (Old made in USA). When i had the Tung-Sol 6SN7GTB new (Russia) i dont recall having the hum. For now is quiter but if the hum comes back i will try this.

Yes it’s really sounds like the tube is the issue. If you touch the tube or slightly move it we’ll it playing is sometimes is a dead giveaway that the tubes the issue.

 

[CJG888]

I have a NOS 1962 Valvo E88CC which sounds divine but is basically a microphone!

Provenance is no guarantee of reliability…

Random failures are always possible. Even in the best tubes.

 

[hmscott]

DC blocker: https://avahifi.com/collections/used-demo-and-quick-ship/products/humdinger-dc-line-blocker

Ok. Will do that. I think is the Tung-Sol 6SN7GTB (Old made in USA). When i had the Tung-Sol 6SN7GTB new (Russia) i dont recall having the hum. For now is quiter but if the hum comes back i will try this.

Yes it’s really sounds like the tube is the issue. If you touch the tube or slightly move it we’ll it playing is sometimes is a dead giveaway that the tubes the issue.

Yup, clean pins and solid placement can make a big difference. I recently acquired 3 FAA-6080WA's and they were tough for me to seat properly and the first couple I seated were lifted on one side and I not only got hum I got a "pop"/arc? when I first powered up the TA-26, so for those I make sure I am standing directly over the socket so I can get them fully seated with no air gaps between the tube base and the socket top.

The Dark Voice 336E which is similar to the TA-26 is known to hum with new 6SN7's, and they recommend leaving the DV336E on overnight with only the 6SN7 plugged in and the 6AS7G pulled out, sometimes it takes 2 or 3 days of running like that for the hum to stop. AFAIK the TA-26 doesn't have that quirk.

There have been a couple of owners in European countries with different power than their TA-26 is wired to accept and they were getting mechanial hum - the TA-26 is humming even without the tubes - and for those situations an RMA back to Xduoo allows parts swap to match their locale power.

Then there are the situations where there are DC ground loops and other problems with the DC power mixing with the AC, and iFi has a couple of new and older solutions for those problems, I'll link them here for future reference:

iFi DC Blocker
https://ifi-audio.com/products/dc-blocker/ <= more compact solution if you need it, they describe symptoms that can be solved with a DC blocker:

iFi GND Defender
https://ifi-audio.com/products/gnd-defender/ <= The GND Defender in the correct way, intelligently detects a ground loop and will cut the ground for that component.

My "hum / Buzz / Whistle" problem was EMI/RFI noise induced into the 5V powerline Ground of the USB connection from my PC (GPU mostly) to my Topping D90 DAC, so my solution was the iFi iDefender+ is for those battling with noisy audio due to unwanted ground loops in their audio chain:

iFi iDefender+
https://ifi-audio.com/products/idefender-plus/

Topping has recently come out with another USB ground loop solution, which I use to connect my FiiO M15:

HS01 USB 2.0 High Speed Audio Isolator
https://www.tpdz.net/productinfo/733226.html

Another general ground loop solution:

Groundhog+ - Does your system suffer from an irritating buzz or hum that decreases when you touch it? It’s missing an earth/ground. You need the Groundhog+.
https://ifi-audio.com/products/groundhog/
Lots of ways to pin point and solve these problems, and we all eventually come upon some them at some point in our lives

 

[ProAcTivo]

Well, before i try everything you guys pointed out i did some experiments. I switched all the tubes to indetify the bad one. Turns out the problem occurs with all of them, even with the Russian made Tung-Sol 6SN7GTB. So, all have the same behaviour. No hum for the first 5 minutes but then the hum shows up. So i dont think is the tubes. I hear no hum for some time but after a while i can hear it clearly on the left driver in my Hd600... will try in a diferent room.

 

[ProAcTivo]

A question for the TA-26 owners. When you switch on the amp, theres no noise at all while is on? Mine emits a little buzz when on. Is not very loud but is clearly audible. Thank you

 

[Ufanco]

Well, before i try everything you guys pointed out i did some experiments. I switched all the tubes to indetify the bad one. Turns out the problem occurs with all of them, even with the Russian made Tung-Sol 6SN7GTB. So, all have the same behaviour. No hum for the first 5 minutes but then the hum shows up. So i dont think is the tubes. I hear no hum for some time but after a while i can hear it clearly on the left driver in my Hd600... will try in a diferent room.

Darn was hoping just a tube issue that’s much easier to fix. There some suggestion posted above I would try them. Might be something on the same power line so differently try it on another outlet. Does hiss change if you touch unit well playing?

Here is a link with sound files of ground loop vs other issue. Cable, other equipment, heck even fluorescent light on same circuit. Kinda odd it starts after unit warms up. Hopefully other would add addition thoughts.

https://www.psaudio.com/ps-how/how-to-find-and-fix-hum/

 

[ProAcTivo]

Yes. When i touch the amp the hum reduce a little bit but not completly. I dont want to start buying things to try to remove the issue. I sent an email to Xduoo. Wil wait for the reply and then i will look into the issue again.

For now, i have to say that this amp produces a wonderful sound with my HD600s. Dispite this noise issues, the amp is absolutly fantastic with the senns. To be honest i was a bit desapointed with the HD600. I EQued them and was able to keep them for some time as the sound was more to my liking. But never totaly satisfied and lost in the music. The TA-26 was a last shot. And it was the right one. Beautiful sound. All kinds of music sound amazing to me.

I have two questions for all TA-26 owners:
-What is the DAC you guys are using with this amp and why do you think it makes a great combo?
-What headphones you recommend with this amp, besides the HD600/650?

Thank you all.

 

[muchacho]

Yes. When i touch the amp the hum reduce a little bit but not completly. I dont want to start buying things to try to remove the issue. I sent an email to Xduoo. Wil wait for the reply and then i will look into the issue again.

For now, i have to say that this amp produces a wonderful sound with my HD600s. Dispite this noise issues, the amp is absolutly fantastic with the senns. To be honest i was a bit desapointed with the HD600. I EQued them and was able to keep them for some time as the sound was more to my liking. But never totaly satisfied and lost in the music. The TA-26 was a last shot. And it was the right one. Beautiful sound. All kinds of music sound amazing to me.

I have two questions for all TA-26 owners:
-What is the DAC you guys are using with this amp and why do you think it makes a great combo?
-What headphones you recommend with this amp, besides the HD600/650?

Thank you all.

I have DAC Topping D10s connected before the TA-26 and I also had problems with interference, but it wasn't hum. Thanks to the ground loop, I received noise from the CPU, GPU and HDD from my PC via the USB cable to the DAC. I temporarily disconnected the ground wire at the power cord and the interference stopped. Then I already knew where the problem was and everything was solved by the already mentioned USB isolator Topping HS01. Of course, I reconnected the power supply ground wire.