Talk to me about “burning tubes”

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Talk to me about “burning tubes”

Post by Unicorn Warrior » Wed Apr 28, 2021 7:30 pm

In all my years of casual playing and occasional gigs. I don’t think I’ve ever burned a tube. Granted, I’ve changed amps like I changed clothes during this time, so part of this is that I haven’t kept a single amp for over a years time. Amps I’ve played include a few mesas, vintage Princeton (with original tubes), bassman, vox HW ac15 and 30, super reverb, etc.. and again, no tube malfunctioning as far as I knew.

I’m wondering if this is attributed to my style which is mostly oriented towards the cleaner guitar tones? I never crank amps and have seen no reason to. I always had enough volume it seemed and if I needed overdrive I kicked the pedals in.

Will tubes last longer if played at lower volumes or does it really matter all that much? I’m just trying to figure out if getting a “tube hungry” amp will really be all that of a hassle for me

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Re: Talk to me about “burning tubes”

Post by Sauerkraut » Thu Apr 29, 2021 1:20 am

I have the same experience. I don't really understand the tube-amps-are-too-much-hassle camp. I suppose if I used a lower wattage amp for the band, I'd run through tubes faster. But as it is, I still use an original GE and an RCA 12ax7 in the V1 and V2 sockets of my Tremolux, and they still rate 8/10 and 7/10 in one of those tube tester things after 50+ years. I can't turn the volume past 2 without overpowering the band, and we're loud enough to need ear protection. I did swap out the 6L6s once during the 15+ years I've used it, because I thought I heard some power tube caused noise, and I read somewhere that they don't last that long. I think it went away after, but I'm not 100% sure. May well have been a shitty, non-isolated power bank instead.

From what you wrote, I think we both use amps in a similar way, so it's good to have some watts to spare (35 is more than enough for me). Still, a cranked tube amp can sound great, and sometimes I prefer to use my 5-watt home practice amp for recording. In theory, it should burn through tubes much faster than my bigger wattage amp (I haven't had it for long enough to find out).

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Re: Talk to me about “burning tubes”

Post by tune_link » Thu Apr 29, 2021 4:27 am

Yeah I'm sure the volume has a lot to do with it. I had an Ampeg V4 that had no issues when I played it at home in my basement at reasonable volumes. It only started exhibiting problems (leading to its eventual demise) when I started playing it in my current band and I often had the volume on at least 6 or 7. The tubes were some of the first things to start having issues and then it just moved on to other parts of the amp before the transformer finally went.

I've always thought of it like running a car at higher speeds. Some cars are meant for that kind of thing and can handle it well. Others or ones which are poorly maintained, older, etc. just can't hack it at that speed for various reasons and the more you run them wide open the more you risk them just absolutely overheating on you, blowing fuses, belts breaking, etc. I think the same could be said for tube amps.

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Re: Talk to me about “burning tubes”

Post by HarlowTheFish » Thu Apr 29, 2021 10:17 am

My H&K Grandmeister lasted about 2 years on its original cheapo unbranded tubes before they died, which was both sad (because I was dead broke and it took me months to get some new ones) and kinda surprising, because I expected that running cranked EL84s into a power soak wouldn't last me very long. The new set cost about $60, some NOS Sovtek military ones, and they've been pretty good to me since June/July or so.

It's like tires -- run them too hard in a context they're not necessarily appropriate for, and they're gonna get wear way faster; give them an easy time in a range they're comfortable in and they'll last years unless there's some kind of defect.

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Re: Talk to me about “burning tubes”

Post by øøøøøøø » Fri Apr 30, 2021 2:57 am

The design and setup of the amp has far, far more impact on longevity than playing style.

AC30s are hard on tubes because they’re typically a bit underbiased and also airflow/cooling around the tubes is rather less than it rightly should be.

A Super Reverb with a good set of 6L6GC, biased to (say) 60% maximum rated plate current dissipation will last and last and last

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Re: Talk to me about “burning tubes”

Post by mynameisjonas » Fri Apr 30, 2021 3:27 am

I've been playing (almost exclusively) tube amps for about 25 years, and I don't think I've never had a tube fail on me. A couple of my amps have needed service and had tubes replaced as a part of it, but I can't recall a single time when a bad/burnt tube was the sole culprit.
But I've pretty much always used 100W amps, and don't rely on power amp distortion to get my sound, so I guess I'm pretty kind to my tubes.

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Re: Talk to me about “burning tubes”

Post by øøøøøøø » Fri Apr 30, 2021 6:14 am

Besides physical trauma, it’s as with most other electronic components: heat is the biggest precipitating factor for failure.

Devices that run tubes rather cool and have good ventilation can keep tubes for decades

There are microphones out there that have run the same tube for 70 years and still sound great.

I’ve played many amps with half-century old tubes that sound fine

Playing dynamics/level may have some impact, but I’d wager it’s fairly minimal compared to things like airflow around the tube

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Re: Talk to me about “burning tubes”

Post by tune_link » Fri Apr 30, 2021 8:45 am

øøøøøøø wrote:
Fri Apr 30, 2021 6:14 am
Besides physical trauma, it’s as with most other electronic components: heat is the biggest precipitating factor for failure.

Devices that run tubes rather cool and have good ventilation can keep tubes for decades

There are microphones out there that have run the same tube for 70 years and still sound great.

I’ve played many amps with half-century old tubes that sound fine

Playing dynamics/level may have some impact, but I’d wager it’s fairly minimal compared to things like airflow around the tube
This makes sense to me. I'm sure biasing plays a role as well. My old JCM800 ran really hot and even though I never had any issues with it I did often worry about it. I have an Orange Rockerverb 100 as my main amp at the moment and it runs considerably cooler than almost any other amp I've ever owned. When you put your hand over the heat vent on the head you can barely feel anything coming out of it even after several hours of use.

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Re: Talk to me about “burning tubes”

Post by øøøøøøø » Fri Apr 30, 2021 11:28 am

Biasing certainly does make a difference, as it directly correlates to heat!

When a tube is underbiased, lots of current flows, which makes a lot of heat (sometimes it’s enough to make the plates glow red)

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Re: Talk to me about “burning tubes”

Post by Larsongs » Sat May 01, 2021 7:27 am

I’ve been playing tube Amps for 40 years & never had a tube burn out..

I play 3-4 hours almost every day/night at all different levels of adjustments.. The volume levels are usually 5-6 or more.. Gigs sometimes higher.

My current collection of about a dozen Amps range from 20 years old to 4 years old. I have done Tube upgrades on my newest Amps.. Vox AC10C1 & my Vox AC15CC1X...

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Re: Talk to me about “burning tubes”

Post by Logrinn » Sun May 02, 2021 7:01 am

I had a silverface Twin Reverb (mid 70's with master volume).
In the band I played in we rehearsed once every week and there was just one way to dial in this beast of an amp to get the massive tone I wanted:
Everything on FULL! (Well, except the bass control which was on 2-3).
So - it was EXTREMELY loud, the amp got seriously hot - and I think after two or three years that amp fell apart. At least the tubes did.
When it started sounding horrible - probably because tubes and perhaps other components failed - I sold it for peanuts.

Wish I had it today though, but ... c'est la vie ...

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Re: Talk to me about “burning tubes”

Post by ohm-men » Mon May 03, 2021 2:46 am

I had power tube failures twice on the PCL VA1956 I have. When I had it checked over, the reason was the power transfo.
The old amp was designed to work with 220 Volts, but nowadays we run close to 240 Volts from our outlet sockets here in the EU.
When my tech measured the plate voltage, it seams the Sovtek's got too much volts, wearing them out much faster then they should if the got the correct plate voltage. The problem is that the 6.3 V plate voltage too much for most 6L6 tubes. After some research it turned out that the JJ 6L6 was designed to work with these higher plate voltages, so they seam to be the answer for this particular amp.

I played a lot of old Fender amps and never had problems with these, even with bad electrolicit camps the amps still ran. (Although a soon as possible these were replaced)

What I did notice is that normally your power tube has a blue-ish arc, which I was told is not bad, but when the tubes start glowing more ruby red, there is big chance something is wrong. I had this once, one of a pair of 6L6's glew red and in a matter of seconds the glass cracked and the amp died...
(Only to be revived later with a new set of power tubes and some propper biasing)

To most amp builders the way Marshall designed his amps makes more sense, by flipping the amp upside down, so the tubes stand on top instead of hanging from underneath as Fender did. as hot air goes up, the chassis get warm. Other amp tech's say it not really important. So I don't know.

And I guess that the higher wattage amps generate more heat. I guess this is why Fender added "slits" on baffle boards of their later 135 Watt amps in the late seventies to have some air flow. I think the late silverface Bassman's had these. (Not sure if Showman had these as well)

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Re: Talk to me about “burning tubes”

Post by Larsongs » Mon May 03, 2021 7:08 am

ohm-men wrote:
Mon May 03, 2021 2:46 am
I had power tube failures twice on the PCL VA1956 I have. When I had it checked over, the reason was the power transfo.
The old amp was designed to work with 220 Volts, but nowadays we run close to 240 Volts from our outlet sockets here in the EU.
When my tech measured the plate voltage, it seams the Sovtek's got too much volts, wearing them out much faster then they should if the got the correct plate voltage. The problem is that the 6.3 V plate voltage too much for most 6L6 tubes. After some research it turned out that the JJ 6L6 was designed to work with these higher plate voltages, so they seam to be the answer for this particular amp.

I played a lot of old Fender amps and never had problems with these, even with bad electrolicit camps the amps still ran. (Although a soon as possible these were replaced)

What I did notice is that normally your power tube has a blue-ish arc, which I was told is not bad, but when the tubes start glowing more ruby red, there is big chance something is wrong. I had this once, one of a pair of 6L6's glew red and in a matter of seconds the glass cracked and the amp died...
(Only to be revived later with a new set of power tubes and some propper biasing)

To most amp builders the way Marshall designed his amps makes more sense, by flipping the amp upside down, so the tubes stand on top instead of hanging from underneath as Fender did. as hot air goes up, the chassis get warm. Other amp tech's say it not really important. So I don't know.

And I guess that the higher wattage amps generate more heat. I guess this is why Fender added "slits" on baffle boards of their later 135 Watt amps in the late seventies to have some air flow. I think the late silverface Bassman's had these. (Not sure if Showman had these as well)
I think it was in Vintage Guitar magazine Articles that Fender Amps were pretty much unavailable in Europe in the 50’s - early 60’s. Vox & Marshall developed their Amp designs using Fender as their blue print.. Then they did their tweaking to make them their own.. But, Leo’s Amp designs were the inspiration......

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Re: Talk to me about “burning tubes”

Post by shoule79 » Mon May 03, 2021 11:34 am

I've never got the "tube amps are so hard to maintain" argument either, i've only swapped tubes on a few amps over the years.

A 76 Vibrolux because I wanted to make it sound better (it didn't).

My new model Vox AC 15 and 30 because I wanted to make it sound better (it did, slightly).

A 90s Blues Jr that was red plating.

Of these only 1 needed it, the Blues jr. The issues with it were caused by poor design though. The power tubes heated up and the solder on the board (the tubes were directly attached to the PCB board) melted and it caused intermittent issues. One tube was bright red, the other was normal. It started cutting in and out, so off to the tech it went, and new tubes were needed due to the stress the melted solder on the board caused the power tubes.

I think every vintage Fender amp from the 60's and 70's i've ever had was still rocking its original tubes. Same with my old Ampegs and Peavey's. My late 70's Princeton Reverb is going in soon for a cap job, I may swap it out while its at the shop just for laughs.

I've had my Mesa Express for 7 or 8 years, 20 hours a week on average, mind you at a civilized volume, still has its original Mesa tubes. My 50 watt JCM 800 ran all on 10 for at least 20 hours a week, always moving around in the trunk of my car or a van, for 10 years, and the tubes that were in it when I bought it in 98 or 99 never gave up the ghost. My tech and I were amazed by that.

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Re: Talk to me about “burning tubes”

Post by Scout » Mon May 03, 2021 4:14 pm

I just had a tube go bad last week on my Ampeg Reverb-oJet. After some intermittent cutting out I noticed blue gassing in the lower section of the power tube only because I face the amp away from me when home playing. Kind of surprised because they were not that old hour wise and never got played anywhere above 4, I did not rebias when I replaced the original Ampeg branded tubes.

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