Are my amp tubes dying early, and if yes, what could I do?

[TB2]

Hello,

Almost 3 years ago, I bought an Elekit TU-8200R kit. I put it together as per the instructions (I'd say I have decent soldering skills) and it ran great.

After about 1 year, one channel started cracking and popping loudly, no matter the volume setting (scary!). I swapped the tubes on the left and right channels and identified that one of the 6L6GC (JJ) tubes might be defective, as the popping traveled with it. I obtained a replacement and alas, the problem was fixed.

However, now, after another 18 months or so, I again get loud popping on one channel. Unfortunately I did not note down which tube is the newer one to know whether it's the original second tube that failed, or the replacement, and whether it happened on the same channel. I ordered another one, and this time I'll make sure to mark which one is newer.

Anyway, this seems odd to me. I couldn't get a conclusive answer as to how long 6L6GC tubes usually last. Some say 2500 to 5000 hours. Others say it depends on how hard you drive them. Others say incorrect biasing affects endurance (but I don't think the TU-8200R could be adjusted). Yet others say that they've used the same tubes for decades on their (guitar) amps.

My amp is connected to a pair of Yamaha NS1000M speakers, source is a Shiit Modi+ DAC, I set the volume to about 50%, and I just listen to music about 150 days a year. Sometimes the amp runs all day. Yes, sometimes I forget to turn it off over night, so the tubes might experience the occasional 30h event. So a very generous estimate would be around 150*15 = 2250 hours per year, which is in line with some of the sources I found.

Well, if this is indeed as expected, I'm kinda surprised this isn't highlighted more prominently in the solid state vs. tube debate. To me, the amp sounds like any other amp. Sounds great. My main reason for buying it was to just try a tube amp and because I like assembling stuff. But I have some solid state amps from the 80s where the only problem is the occasional corroded control knob, and I've been using them just as much. They, too, sound great. I mean, I can afford it, but spending 30 bucks on a new tube every year seems weird.

If it's not expected, what could I possibly do? It works and sounds just fine most of the time. Kinda doubt there's something wrong on the inside, but I'm no expert.

Any opinions?

Thank you!

PS: This is the assembly guide with schematics and all

 

[BDWoody]

Any opinions?

No, but just wanted to give this a bump up to make sure you get some visibility.

Sounds like a frustrating problem I hope you get an answer for. Do you like the amp otherwise? Would you buy/build another one?

 

[JSmith]

18 months or so

Save typing out too much, a decent summary here, which seems fairly on the mark when used in power amp;

How Long Do Amplifier Tubes Last?

Discover the factors that influence amplifier tube lifespan and learn how to maintain your tube amp for optimal performance. A must-read guide for audiophiles.

apos.audio

lifespan of 1,000 to 2,000 hours

Yes, sometimes I forget to turn it off over night, so the tubes might experience the occasional 30h event

Do you generally follow the below, in particular warm up and cool down?

Warm-up time: Allow your amplifier to warm up for a few minutes before playing audio. This gives the tubes time to reach their optimal operating temperature, reducing stress on the tubes.
Cool-down time: After using your amplifier, let it cool down for a few minutes before turning it off. This helps prevent thermal shock, which can cause the tubes to crack or fail prematurely.
Proper ventilation: Ensure your amplifier has adequate ventilation to dissipate heat. Overheating can shorten the life of your tubes and other components.
Clean your amplifier: Regularly clean the interior and exterior of your amplifier to remove dust and debris, which can obstruct airflow and cause overheating.
Handle with care: Tubes are fragile, so handle them with care when installing or replacing them. Avoid touching the glass with your bare hands, as the oils from your skin can cause hot spots and premature failure.
Use a standby switch: If your amplifier has a standby switch, use it to extend the life of your tubes. The standby mode allows the tubes to warm up without passing audio, reducing wear and tear on the tubes.
Store your amplifier properly: When not in use, store your amplifier in a cool, dry place away from direct sunlight, extreme temperatures, and moisture.
Conclusion
The lifespan of amplifier tubes depends on various factors, including usage, quality, and maintenance. By understanding the different types of tubes, their lifespans, and the signs that indicate they need replacement, you can ensure your amplifier continues to deliver exceptional sound quality. Proper care and maintenance can prolong the life of your tubes and keep your amplifier sounding its best for years to come. Explore Apos Audio's extensive collection of amplifiers to find the perfect addition to your audio setup.

JSmith

 

[Roland68]

Hello,

Almost 3 years ago, I bought an Elekit TU-8200R kit. I put it together as per the instructions (I'd say I have decent soldering skills) and it ran great.

After about 1 year, one channel started cracking and popping loudly, no matter the volume setting (scary!). I swapped the tubes on the left and right channels and identified that one of the 6L6GC (JJ) tubes might be defective, as the popping traveled with it. I obtained a replacement and alas, the problem was fixed.

However, now, after another 18 months or so, I again get loud popping on one channel. Unfortunately I did not note down which tube is the newer one to know whether it's the original second tube that failed, or the replacement, and whether it happened on the same channel. I ordered another one, and this time I'll make sure to mark which one is newer.

Anyway, this seems odd to me. I couldn't get a conclusive answer as to how long 6L6GC tubes usually last. Some say 2500 to 5000 hours. Others say it depends on how hard you drive them. Others say incorrect biasing affects endurance (but I don't think the TU-8200R could be adjusted). Yet others say that they've used the same tubes for decades on their (guitar) amps.

My amp is connected to a pair of Yamaha NS1000M speakers, source is a Shiit Modi+ DAC, I set the volume to about 50%, and I just listen to music about 150 days a year. Sometimes the amp runs all day. Yes, sometimes I forget to turn it off over night, so the tubes might experience the occasional 30h event. So a very generous estimate would be around 150*15 = 2250 hours per year, which is in line with some of the sources I found.

Well, if this is indeed as expected, I'm kinda surprised this isn't highlighted more prominently in the solid state vs. tube debate. To me, the amp sounds like any other amp. Sounds great. My main reason for buying it was to just try a tube amp and because I like assembling stuff. But I have some solid state amps from the 80s where the only problem is the occasional corroded control knob, and I've been using them just as much. They, too, sound great. I mean, I can afford it, but spending 30 bucks on a new tube every year seems weird.

If it's not expected, what could I possibly do? It works and sounds just fine most of the time. Kinda doubt there's something wrong on the inside, but I'm no expert.

Any opinions?

Thank you!

PS: This is the assembly guide with schematics and all

You should measure the operating parameters on both sides with the same tube and check whether they are within the specified range and correct them if not.
Then do the same again with the second tube.

An electron tube is a very difficult product to manufacture and the materials used, and there are clear differences in quality. But you have to look in the relevant forums for that.

 

[Mikig]

hi,
have you tried to open it. you could start with a visual examination, very simple. You might notice something that is no longer in order. If you have the diagrams you could do a further check. Or ask someone who has electronics experience.

Apart from this, I bought a tube amplifier that the seller had been told had just been put in with new tubes. When I turned it on it made a rumble for a few seconds.
Bottom line I ordered brand new tubes, to test. Now when I turned it on there was no noise, no background hum. It's fine.
Often the tubes that are sold or given as new are not. Only an examination with the tube tester can confirm their state of wear. It is difficult to establish it by "ear".
Furthermore they should always be purchased in groups. Possibly already matched with each other.
Now I don't trust the too many tubes on sale and especially the too many NOS that circulate on the net.
When I helped out in a Hi-fi shop we tried many with tube testers and too often those sold as NOS or new were already quite worn out... unfortunately.
but I remember my friend telling me that an old trick, the first test, was to look at the upper silver part. The less shiny it is and the more blackened it is and the more the tubes are used.

 

[Roland68]

hi,
have you tried to open it. you could start with a visual examination, very simple. You might notice something that is no longer in order. If you have the diagrams you could do a further check. Or ask someone who has electronics experience.

He soldered and assembled it himself

 

[Mikig]

He soldered and assembled it himself

yes, but maybe in 3 years some flaw may have come out. All it takes is a solder that didn't hold, or a component that was compromised...

 

[SIY]

Hello,

Almost 3 years ago, I bought an Elekit TU-8200R kit. I put it together as per the instructions (I'd say I have decent soldering skills) and it ran great.

After about 1 year, one channel started cracking and popping loudly, no matter the volume setting (scary!). I swapped the tubes on the left and right channels and identified that one of the 6L6GC (JJ) tubes might be defective, as the popping traveled with it. I obtained a replacement and alas, the problem was fixed.

However, now, after another 18 months or so, I again get loud popping on one channel. Unfortunately I did not note down which tube is the newer one to know whether it's the original second tube that failed, or the replacement, and whether it happened on the same channel. I ordered another one, and this time I'll make sure to mark which one is newer.

Anyway, this seems odd to me. I couldn't get a conclusive answer as to how long 6L6GC tubes usually last. Some say 2500 to 5000 hours. Others say it depends on how hard you drive them. Others say incorrect biasing affects endurance (but I don't think the TU-8200R could be adjusted). Yet others say that they've used the same tubes for decades on their (guitar) amps.

My amp is connected to a pair of Yamaha NS1000M speakers, source is a Shiit Modi+ DAC, I set the volume to about 50%, and I just listen to music about 150 days a year. Sometimes the amp runs all day. Yes, sometimes I forget to turn it off over night, so the tubes might experience the occasional 30h event. So a very generous estimate would be around 150*15 = 2250 hours per year, which is in line with some of the sources I found.

Well, if this is indeed as expected, I'm kinda surprised this isn't highlighted more prominently in the solid state vs. tube debate. To me, the amp sounds like any other amp. Sounds great. My main reason for buying it was to just try a tube amp and because I like assembling stuff. But I have some solid state amps from the 80s where the only problem is the occasional corroded control knob, and I've been using them just as much. They, too, sound great. I mean, I can afford it, but spending 30 bucks on a new tube every year seems weird.

If it's not expected, what could I possibly do? It works and sounds just fine most of the time. Kinda doubt there's something wrong on the inside, but I'm no expert.

Any opinions?

Thank you!

PS: This is the assembly guide with schematics and all

I'm guessing that the issue is the "auto-bias" circuit. Note whether the popping always starts in the same channel. Also, check the voltage at Point 17 (the output tube cathode) and see if it's running rich in either channel.

With a properly run circuit, the output tubes should last for years.

 

[Ruhled]

I would clean both the tube pins and sockets with 99.9% alcohol meant for electronics using a set of small, round nylon bristle brushes you can get from Amazon. I also run some crocus cloth around the pins a bit.

I find I have to do this about annually with some of my amps. They will start rustling and popping when it's time for a cleaning. Even pins that look clean probably aren't after some hot/cold cycles and time.

 

[Gounsbairg]

How To Tell If A Vacuum Tube Is Bad​

How To Tell If Your Vacuum Tube Is Bad

We have some tips and tricks to help determine if you have a bad vacuum tube when you do not have access to a tube tester.

blog.thetubestore.com

 

[rank]

I have had three tube amps (+ a preamp), never had this problem, the "remote fault diagnosis" is a perilous exercise. A colleague had a similar problem with a big brand, he ended up with rather expensive Russian tubes and ended up selling this power amp. Several repairers including the after-sales service of the importer I think had found nothing.And I hope they had checked each weld.

 

[Saponetto]

Hi,
Some time ago I helped one of my pals to assemble one of these kits, don't remember if it was actually the same item but it resembles a lot.
He encountered similar problems and, just as you did, replaced the tubes to get fully operative amp just to face similar -cracks- after several weeks of flawless work.

My 5 cents:
-double check the snap connectors that are to interconnect the boards, these are nothing to write home about quality and are subject to oxidixe quickly.
-once did this, try to measure the idle plate current in order to be sure that the "auto bias" works as expected.
It should be within 40-50mA range.

 

[mhardy6647]

Unfortunately,as @SIY says, voltages need to be checked. I say "unfortunately" only because there is some risk for a neophyte, if only the risk occasioned by fear.

 

[Saponetto]

Of course you are right.
As per every tube device, a big disclaimer has to be exposed before attempting any access within.
Something like "Beware of the Capacitors".

 

[mhardy6647]

Of course you are right.
As per every tube device, a big disclaimer has to be exposed before attempting any access within.
Something like "Beware of the Capacitors".

The capacitors aren't what I worry about - it's the B-plus.
My father was a self-employed TV repairman. He used to troubleshoot suspect (electrolytic) capacitors by jumpering them with a good capacitor. Once in a while, he'g get bitten. Invariably, as he reflexively jerked his arm out of the set, he'd gouge it on some metal bit his poor arm encountered on the way out.

Mind you, if we're talking about something like 845 output tubes, a bit more care is indicated.

 

[TB2]

Thanks everyone for your replies!

Do you like the amp otherwise? Would you buy/build another one?

I like it a lot. Like I said though, I'm not able to hear any difference to my solid state amps (I use a Sansui AU-G50X and a Kenwood KA-1100D on the same speakers at other locations). It's really more about the novelty of glowing tubes. The assembly instructions were great. I would buy it again if I were able to figure out the tube issue. It's the first amp I bought new as I usually just bought good stuff from the 80s available for cheap. Now I'm kitted out, probably not gonna need any more gear for a long while.

Save typing out too much, a decent summary here, which seems fairly on the mark when used in power amp;

How Long Do Amplifier Tubes Last?

Discover the factors that influence amplifier tube lifespan and learn how to maintain your tube amp for optimal performance. A must-read guide for audiophiles.

apos.audio

Do you generally follow the below, in particular warm up and cool down?

Thank you for the resource and for pointing this out. I was unaware that it's better to wait a bit.

hi,
have you tried to open it. you could start with a visual examination, very simple. You might notice something that is no longer in order. If you have the diagrams you could do a further check. Or ask someone who has electronics experience.

I'll have a look inside. I live in a humid environment so it's possible something went bad.

Often the tubes that are sold or given as new are not. Only an examination with the tube tester can confirm their state of wear. It is difficult to establish it by "ear".

I kinda trust the seller Elekit - I obtained the kit and replacement tubes directly from them.

I'm guessing that the issue is the "auto-bias" circuit. Note whether the popping always starts in the same channel. Also, check the voltage at Point 17 (the output tube cathode) and see if it's running rich in either channel.

With a properly run circuit, the output tubes should last for years.

I will consider if I am able to do that safely

I would clean both the tube pins and sockets with 99.9% alcohol meant for electronics using a set of small, round nylon bristle brushes you can get from Amazon. I also run some crocus cloth around the pins a bit.

That, I can definitely do.

I find I have to do this about annually with some of my amps. They will start rustling and popping when it's time for a cleaning. Even pins that look clean probably aren't after some hot/cold cycles and time.

So after cleaning, the popping is gone?

Thanks again, I might report back when I had some time to look inside or at least clean the contacts.

 

[JohnnyAudio]

Check AC line voltage. You can use a Variac to lower the line voltage to save tubes.
I set my 123 VAC line to 115 VAC.

 

[raindance]

Check AC line voltage. You can use a Variac to lower the line voltage to save tubes.
I set my 123 VAC line to 115 VAC.

Yes! What is the rated voltage on the amp? 110? I used an APC Line-R series unit to step my mains voltage down for Chinese-made amps that were designed for 110 volts rather than our 120 nominal volts (actually 128). This was especially helpful for so called auto-bias amps that ran a bit "rich" otherwise. When the mains is too high, the heaters and anodes both get too much voltage creating a couple of premature failure points.

 

[genesisaudiorack]

i have used tubes for the rated amount and maybe even beyond the rated amount considerably. its really hard to say how long they will last for. there are also roll able variations and some of those tubes can last alot longer than others. i have practiced listening to my amps for average 6 hours at ass time. i think this allows them to last a little longer as its the cold to hot cycles that wear them out. so i perceive the ownership of tubes as how many cycles can i turn it on and off for. because the cycle average is the time frame; it may go out, far before the hours its rated for. some hardware is harder on tube startup.....and some shunt the voltages pretty quick on shutdown. i have read that ramp in and ramp out tends to make tubes last longer than the simple ramp up and shunt off. a tube is just a nerdy weak azz light bulb. if you line up 20 light bulbs and just keep switching them on and off you'll see them start to go out unpredictably. something cool to consider, if you switch on and off through out the day when you listen, its best to turn it on and leave it on and play quiet or mute the system. then listen as needed. dont just turn on and off. its hard on some amps

 

[Ruhled]

So after cleaning, the popping is gone?

Yes. You can also tell if you just barely nudge the tube a bit. If it rustles or pops it's likely dirty.

Also avoid tube rolling. This just jacks up sockets and pins faster IMHO. Plus you can get pretty much the same effect just by doing 0.5 or 1db bass or treble shelves lol.

No, I'm not a tube or analog "purist", but I like the repairability of valve amps. I still have a st70 from 1962 with nothing replaced but the can cap. Original Dynaco output tubes too. This stuff can last virtually forever.

Hit me up if you need anything. Good luck.