[Les Lammers]

The following is a stupid question, but I'm a tube neophyte:

When a power tube fails, can it ever damage the rest of the amp or is the damage just confined to the tube?

Yes, it is possible to damage the amp but that depends on the amp. It does not happen often, What amp are you using?

[trackball02]

I have a Van Alstine Ultravalve.   Great amp, by the way.

[Les Lammers]

Call Frank and ask him about it. 

[newzooreview]

About a month ago, all of a sudden it stopped doing its magic. The tubes started to produce mind-collapsing rackets now and again. It got more frequent. I got scared it might stifle my little 3/5a's throat to death.

Yes, the tubes sounded glorious. But, mind you, it only did so for two months. Do not believe the new replicas will last longer than the old sturdy valves, unless you happen to be a lucky picker.

I had exactly the same experience with Psvane tubes from Grant Audio, and they tried to tell me that my amp was at fault. I dialed in the bias and checked it over the first two weeks to make sure everything was stable and happy. They sounded excellent. Then after six more weeks the tubes started crackling loudly (well, at least one of them) and tripped my amp's over-current protection.

So, the Psvane's are to be avoided (To get the Philips Holland replicas I had returned a regular quad of their EL34s that also started crackling after 10 days and tripping my amp).

Two sets of tubes over 3 months--same horrible results.

[rbwalt]

not quite on the subject but i tried some JJ E34L's to replace my old NOS Siemens EL34's and they sounded very good until at about the 150 hr mark they decided to go south. i had one go and take out it's mate next to it. replaced the fuse and it was ok for a time and it went again. stuck in a replacement and it was ok. then had another one go to the point were it was turning cherry red! it was so hot i could cook a hot dog over it. now these tubes came well matched and tested. i have never in all my yrs with tubes have this happen to me. now as far as the sound. they were very natural and relaxed in the mids and the bottom end was deep, strong and very well defined. the top end was very open and smooth with a nice delicate pristine nature. over all the tube is on the warm side. a nice tube but reliability sucks and i am sure i am not alone. guess it was my turn to get some bad tubes though that has not happen in a long time.

[ludusfamulus]

I had exactly the same experience with Psvane tubes from Grant Audio, and they tried to tell me that my amp was at fault. I dialed in the bias and checked it over the first two weeks to make sure everything was stable and happy. They sounded excellent. Then after six more weeks the tubes started crackling loudly (well, at least one of them) and tripped my amp's over-current protection.

So, the Psvane's are to be avoided (To get the Philips Holland replicas I had returned a regular quad of their EL34s that also started crackling after 10 days and tripping my amp).

Two sets of tubes over 3 months--same horrible results.

Sorry to hear that. Oo-ps! bane tubes turn out to be a vicious lottery to some, at least to us.
BTW, I got a nice quad of mullard xf2's at a decent price from eBay. They sound awesome and they are truly reliable.
Why are old goons so much better than the new crooks?

[rbwalt]

not fun is it. i had NOS Siemens in my old RM9MK2 for almost 11 yrs and without a problem!!! go figure.my JJ E34l's which were quite good have now been replaced with some Valve Art EL34's which are still breaking in. the tube is very similar in character to the Siemens.maybe a bit more on the warm/vintage side. so i am keeping my fingers crossed on these. guess it is just the luck of the draw and where they fall on the bell curve of testing. maybe we should try to find out on what day the tubes were made.if they were on a monday or friday stay away from them. that is what they use to say about buying a American car.a bit of levity here.

good luck to all of us who love tubes!!!

[ken]

I know this is a little off topic but do tubes  become "tired sounding" where some of the luster and sparkle gradually fade, and do power tubes generally have a shelf life where they degrade without failing?  I guess that was just a different way of asking the same question  I'm guessing that some of the older NOS tubes probably last longer then many reissues but is there any rule of thumb that people follow for power tube replacement?

[rbwalt]

yes they can become tired sounding as they age. shelf life depends on how hard the amp is on the tubes. some amps run high bias that can really shorten a tubes life. some go away nicely and others may take a different path. i had a new JJ E34l  go and take out it's partner. by take out i mean the two tubes blew fuses at the same time. once on startup and about 30 mins into listening. another time one of the tubes( same ones) blew but did not take the other out. so i replaced that one thinking it was causing the problem and it seem to work. i had another one get so hot it was turning red. it had run away bias. so i replaced its partner thinking that the other was working to hard and that seemed to have helped. now these tube did not even have 150 hrs on them. needless to say they are no longer in the amp. it now has the EL34 Valve Arts which have about 25 hrs on them and are continuing to break in so we shall see. sometimes it is a crap shoot and those JJ's were custom matched as are the Art's. if a amp is designed properly one should get at a bare min 2500 hrs on its output tubes. here again it all depends on how  the amp was designed to get the max wattage out the given # of tubes. push them hard then the life span drops fast. just like car tires. the harder you drive the faster they wear out.

[pehare]

All the above & I try to guesstimate the number of hours I have on output tubes & keep an eye on the gettering inside the tube.  In my experience when the getter or silver inside the tube dissipates to mostly all grey or dark - it's a good sign they're about toast.  In most cases they still hold bias fine but sound lackluster.  I'm no longer a tube roller - I know what works well w/no drama & stick with it.

[rbwalt]

there you go. yes my bad tubes held bias also . sometimes keeping them in balance can be a issue when they get older. all tube rolling does after awhile is cause wear and tare on the sockets and if they are mounted on a board lose solder joints. all in all when it starts to sound like SS( sorry all you SS guys) and crap then you know it is time.

happy listening!!!

ps. i can remember growing up with a black and white tv . its tubes were always going bad and watching the repair guy test them. i remember going to the local Woolworths store and seeing their tube testers.

[doctorcilantro]

Wow, Grant Fidelity supposedly uses an Amplitrex and they even claim to weed out the bad ones from the factory.

I know the PSVANE Type IIs I have are bad and I will take to my friend's Amplitrex soon.

I am very skeptical about these PSVANE tubes now.

[doctorcilantro]

I broke the third tube on the trip but here are the results of the other two PSVANE Type II EL34 from tube-sale.com (Linda):

tested on an Amplitrex AT1000.

Tube 1 of the Psvane 6CA7 pair: Emmisions 127%, GM 94%, H to K leakage 0 and Gas was a whopping 999.9 mA, so this one was very strong but with SERIOUS gas problems which would equal lots of noise issues.
 
Tube 2 of the Psvane 6CA7 pair read 68.6% Emmisions and 70% GM, 0 H to K leakage and 1.6mA Gas. This one should still be useable in most circuits, but it is not strong by any means. the 1.6mA of Gas is normal and is nothing to worry about.

[DaveC113]

I've pretty much given up on new tubes. Even the ones that sound good won't last and most of them don't sound as good as old stock. Some, like Psvane, are among the most expensive options too.

[Jon L]

I had exactly the same experience with Psvane tubes from Grant Audio, and they tried to tell me that my amp was at fault.
So, the Psvane's are to be avoided (To get the Philips Holland replicas I had returned a regular quad of their EL34s that also started crackling after 10 days and tripping my amp).

Two sets of tubes over 3 months--same horrible results.

It's a real shame that Psvane's are turning out to be such duds after all the hype and the high prices.  The 90 day limited warranty is another shame given the high prices.
--------------

"All vacuum tubes come with 90 days limited warranty unless otherwise mentioned on the product listing page. Such a warranty covers manufacturer defects but not improper usage by the end user. Please note that a defective tube will usually fail in 30 days of normal use and we will provide replacement free of charge except shipping.

Exclusive remedy: Any implied warranty related to products purchased from this website shall be limited to the duration of the above limited warranty period and the seller reserves the right to replace or refund at its sole discretion. Under no circumstances the seller is liable for any consequential or incidental damages or losses."

[Captainhemo]

I've been running a quad of the Canada Fuller EL34G's for about 5 months now and so far so good.  Biaas  has been steady  and the tubes sound  great.  They have a wonderful rich mid range and  extend well  into the top  and bottom.  Bass is clean and tight  and the hights are very natural, lots of clean dtail  with no fatique.
I have only heard a few other  EL34 family tubes to compare with but these  are by far the best sounding I have heard (very nice to  lookat as well not that  it really matters) .  If they continue to hold up,  I'll for sure be  buying another set when these start to fadel, hopefully a long ways down the road

I got mine from Partsconnexion on sale fo about $240 / matched quad and they come with a  full 1 year warranty if you get them from  PC.  I see they are back to their normal price at the moment but I'm sure they will   go back on sale.
I've also heard  a few comments regarding how good the KT88's sound
http://www.partsconnexion.com/tube_new_fuller.html

-jay

[raindance]

After trying flaky JJ KT77's and E34L's I settled on Valve Art EL34-B's from Antique Electronic Supply. They seem to do a good matching job (my amp takes two quads). No premature failures out of 16 tubes so far and they settle in nicely with time and sound great. The sound differences between output tubes don't seem all that great. Main difference to my ears was that the KT77 has nice extension at the top, but the EL34-B isn't bad at all.

I drive Maggie 1.6 speakers with my 100 watt per channel amp and they sound great.

[DaveC113]

I just managed to find some (pre-JJ) Tesla EL34s for $40/pr and they are excellent. Probably my favorite so far. The reissued GL KT77 were good but one of them failed early like all new tubes seem to do. Also got Mullard XF3s and some Japanese tubes that are almost identical, both are really good and sound the same. My Winged-Cs are great too. Still haven't tried the more expensive Mullards or RFTs. I'm staying away from new tubes from here on out.

[raindance]

I tried the Teslas also. They were quite good but emitted a really strange smell when hot.

[doctorcilantro]

I just managed to find some (pre-JJ) Tesla EL34s for $40/pr and they are excellent. Probably my favorite so far. The reissued GL KT77 were good but one of them failed early like all new tubes seem to do. Also got Mullard XF3s and some Japanese tubes that are almost identical, both are really good and sound the same. My Winged-Cs are great too. Still haven't tried the more expensive Mullards or RFTs. I'm staying away from new tubes from here on out.

Funny I am using the same tubes now. I think it is pretty ludicrous that the Chinese tube makers don't simply doing better QC, and support their "dealers" with accurate test results.

I think it is pretty obvious many new production tubes are a scam, and they don't stand behind them because the quality sucks. PSVANE is the pits.