Tubes, Tyler, and the Power of the ST-120

Last Wednesday I took possession of brand-new handcrafted Tyler Acoustics Halo 2 speakers. They are no-frills, three-way, sealed-enclosure, medium-sized floor-standers of  moderate price. Upon first hooking them up, it seemed inevitable that I would need subwoofer support, which for me means two subs, hooked up in stereo. After an interesting series of occurences, I was forced to install a new set of KT-88s that had been waiting in the wings.
Lo and behold! - suddenly I had all the oomph I craved. I never knew that output tubes age like humans - they get feeble and unable to perform (!!!).
So now I have a system which boggles the mind. The sealed-box Tylers have an incredibly tight and deep low end. No more bass management issues. When properly set up in my modest space, they perform flawlessly in harmony with the VTA ST-120.
The lesson here is twofold: first, output tubes degrade so slowly and gradually that you might not notice that they are not aging gracefully. Mine were 19 months old. If one hadn't died, I wouldn't have realized that I needed to say goodbye to all four - been nice knowin' ya, guys! Now go lie down {forever}.
Second, anyone in the market for a new speaker experience owes it to himself to investigate Tyler Acoustics. Bob Latino and deepee99 swear by theirs. And don't be afraid of the more modest, "lower-end" lines. They are incredible, hand-crafted, superbly planned and executed speakers. Silk dome tweets give fatigue-free listening, such as I've never experienced!
So watch those elderly tubes - don't be afraid to let go. And consider Tyler Acoustics. Best wallop for the buckaroo I've ever spent - after the VTA ST-120, of course! {Unpaid and unsolicited endorsement}.

Couldn't agree more, Kentley. Even after reading the New Yawk Times story this a.m. about the listening rooms in London, I am not convinced you can top Tylers, sized right for the listening room of course.
Ty is one of those guys, like Bob Latino and Roy Mottram and their ilk, who are doing this revival in quality music.
Plus, I can't stand London weather and their crappy attitudes.

deepee: "Plus, I can't stand London weather and their crappy attitudes."
Reminds me of my encounter with Keith Moon backstage at a show I opened for Da Who in '69:
"Gogh anee huppahs?" says he. I had no clue. Coulda been Swahili. Pete was gracious enough to translate "He wants some speed, Mite". Yes, London is a cold, wet hell.
Bad for the mood, and the teeth, and probably for tube gear to boot.
He should have asked "Got any Tylers?" Then I would have been able to service him - 47 years later.
Back to regularly "shedualed" banter....

Is 19 months (yikes) a typical replacement interval for a quad of power tubes? Not sure I can afford to keep switching them out that often. Any tricks folks can recommend to stretch out tube life? Like the type of tube, ie 6550 vs KT88 vs KT120? Or sticking with a particular brand?

19 months doesn't seem like a long time. How many hours would you say you had on those tubes?

monkuboy wrote:19 months doesn't seem like a long time.  How many hours would you say you had on those tubes?  

My guesstimate is between 2000 and 3000 hours. That's actually in the ballpark for normal output tube life. Let's say I buy a quad of Genalex KT-88s from Jim McShane. That runs around $225. If they last about 20 months it's only $11-$12 per month. Chances are good that the electricity to blast them would cost almost as much. So it doesn't seem like such an extravagance to me.

And no, there's apparently no tricks to extending output tube life, except to keep the bias on the low side. There does not seem to be any particular brand or type, either. Sometimes you get lucky. But there's nothing one can do to postpone the inevitable aging process. The only sure things are tube death and taxes.

Kentley wrote:

monkuboy wrote:19 months doesn't seem like a long time.  How many hours would you say you had on those tubes?  

My guesstimate is between 2000 and 3000 hours. That's actually in the ballpark for normal output tube life. Let's say I buy a quad of Genalex KT-88s from Jim McShane. That runs around $225. If they last about 20 months it's only $11-$12 per month. Chances are good that the electricity to blast them would cost almost as much. So it doesn't seem like such an extravagance to me.

And no, there's apparently no tricks to extending output tube life, except to keep the bias on the low side. There does not seem to be any particular brand or type, either. Sometimes you get lucky. But there's nothing one can do to postpone the inevitable aging process. The only sure things are tube death and taxes.

Thank you for the reply. So that comes out to about 3.5-5 hours per day on average. My usage is through no choice of my own a lot less.. but one of these days I'll catch up! The cost per time period for those tubes is reasonable considering what you get.

I wish Bob Latino would weigh in on this, but I, too have been labouring under some popular misconceptions about tubes and tube life and have been set straight by some of the wiser folks on this forum and elsewhere, so I'll pass along what I have gleaned from speaker-makers and tube resellers:
As a general rule-of-thumb, a tube is like an incandescent light-bulb. The longer it burns, the more prone it is to failure. (Caveat: tubes do deteriorate over time, unlike a light bulb, which either works or doesn't.)
Tubes run full-tilt all the time. So volume settings are irrelevant to their longevity. The significant variable affecting tube life -- as Kent mentioned -- is bias. If 0.6v/tube works, try .55 or even .5. How many more hours you get by lowering bias is not something I know, but if you want full-time
Class A at a higher-than-recommended bias it will cost you tube life. How much, I cannot vouch. I had a modified M-125 run for perhaps a month at twice the "normal bias" on the KT-88s (Genalexes) and there were no failures other than whatever died to double the bias. Per Bob's advice in the owner's manual I check tube bias monthly, so the double-bias thing could have erupted anywhere within those intervening 30 days. I doubt they ran at double-juice for a whole month, but there was no visible or audible impact on the machinery or the sound -- in other words, they didn't red-plate or sound weird. (Being on the cautious side, I chucked the quad; a $400 cock-up.)
Again, what I have been told is to expect up to 10,000 hours out of a pre-amp or driver tube, and 2-3k hours from output tubes. I have heard people say you can squeeze 10k hours out of an antique Tung-Sol or GEC KT-88/6550-type output tube, but I bet not, given the higher plate voltages that our Dynaco derivatives operate on.
A personal tube myth of mine has been debunked, as applies to powered subwoofers. Powered subs do NOT alleviate the load lifted by the power tubes. I had ASSuMEd such would be the case but it is not, whether the cross is made between the pre-amp and power amp Vandersteen-style, or directly at the speakers, Tyler-style. Your output tubes are running full-fart, regardless.
So the only variables I can discern are bias settings, and actual operating hours. As the planet's tube pro, Andy Bowman, is fond of saying, "Don't turn your back on the bastards." If you're not actually listening to them, turn them off. That applies to pre-amps as well as to power amps. A few old-timers say they leave the pre-amps on all the time, as they do take an hour or two to warm up. But as Roy M. would say of pre-amp tubes, "How many electrons do you want to waste? There are only so many of them in a tube."
Let's face it: the price we pay for good sound is in the cost of the consumables. Get over it.

Just for info:
the 6550 ( JJ ) in my vta-70 has 2792h and still keeps bias steady ( not changed since new)

An hour meter is a cheap device to measure actual hours. See ebay !

peterh wrote:Just for info:
the 6550 ( JJ ) in my vta-70 has 2792h and still keeps bias steady ( not changed since new)

An hour meter is a cheap device to measure actual hours. See ebay !

Hour meter sounds like a good idea. Link?

LeGrace wrote:

peterh wrote:Just for info:
the 6550 ( JJ ) in my vta-70 has 2792h and still keeps bias steady ( not changed since new)

An hour meter is a cheap device to measure actual hours. See ebay !

Hour meter sounds like a good idea. Link?

http://www.ebay.com/itm/Rectangle-LCD-Hour-meter-gauge-924-48-90-volt-golf-cart-forklift-9-80VDC-generic-/121052465515?hash=item1c2f4a096b

There is several brands, i had 12V at hand, but if you only have 6 use
one that runs by that. Some may even be run by 120V AC .The importent thing
is that thay are quite ( one doees not want a mechanical one that
"tics" evere 6s :-)

You can just keep a written log, but I forget to; looking at my occasional jottings, looks to be about 5 hrs/day. That's ~ 1500 hours per year. Maybe a sand-powered sound-bar for TV watching could cut that in half.

I keep the 6550's in my VTA120 running at a cool .4 VDC for longer tube life. I've had one good channel that seems well matched and hasn't changed in bias since I got them. The other channel is a different story. I had one tube fart and die on me. Got a replacement which is holding up well but now the other older one is rising in bias. I had to set that pair to .5 just to match them. Probably just going to get a whole new set of tubes one of these days. I really want a set of KT120's but also considering KT88's.

corndog71 wrote:I keep the 6550's in my VTA120 running at a cool .4 VDC for longer tube life.  I've had one good channel that seems well matched and hasn't changed in bias since I got them.  The other channel is a different story.  I had one tube fart and die on me.  Got a replacement which is holding up well but now the other older one is rising in bias.  I had to set that pair to .5 just to match them.  Probably just going to get a whole new set of tubes one of these days.  I really want a set of KT120's but also considering KT88's.

Unless your listening room is the size of the Taj Mahal, I'd save up the bucks to go for a good set of KT-88s (Genalex). I've gone hot and cold on the KT-88 v. KT-120s, but think the KT-88s, albeit more expensive than the TS-120s, give a more fulfilling sound.
Driver and pre-amp tubes will influence your sound far more than the big output bottles, and are far cheaper to experiment with.
If you're happy with a .4 VDC bias setting for your (am assuming here) antique 6550s, then the Gold Lion KT-88s set at .5V will live long and happy, as will you.

Kentley wrote:
The lesson here is twofold: first, output tubes degrade so slowly and gradually that you might not notice that they are not aging gracefully. Mine were 19 months old. If one hadn't died

Playing the devil's advocate here ... hey, it's what I do.

I hate blanket statements. I've had older tube sets that may lose a bit of power, but strangely enough, develop better overall sonics. Go figure. If I have to twist the knob a bit to get the boost back, no worries, eh. Any power loss I've seen hasn't been all that significant anyways.

What puzzles me is how often a reputable company has "issues" providing a replacement tube for a matched set that develops a deader. Had that happen with both Psvane and TAD, and they could get ballpark close, but no kewpie doll. I can see their side - even if they do have a closer match in a set, they're not gonna break it for lil ol' me, and it wouldn't make much sense to stock a bunch of singles for us cheapskates trying to get some more mileage out of a broken set.

On the bright side, close seems to be close enough - I'd forgotten how good those Psvane's sounded, and red plating one didn't seem to bother the rest. Probably helped that I was able to hit the power off FAST ... let's hear it for night listening with the lights out! The bad TAD (bad tad, bad tad!) just went quiet ... good heater, but no output ...

PS ... I'm good for maybe three or four hours a week. Seldom listen to background music, and if I do, it's using the sand side of my system. LISTENING that requires tubes to be done right is usually late nite when I can sit back and enjoy.

Good points all, Mr. sKiZo. I should perhaps have been more specific in my description of A Tube Set's Demise.
Along with a gradual power loss, as you describe, which for me was also tolerable to a point, the issue I was having which was not so excusable was a real loss in headroom. "Normal" levels and dynamics remained within tolerance; it was the heavy peaks which suffered - what deepee and I call "1812 Overture Moments". The output tubes lost the ability to reproduce transients. And THIS happened fairly rapidly - in a matter of a few weeks. It may have been longer; I'm not in the habit of blasting all that often. Now I know that I should test the output more than occasionally - this symptom is easy to hear and is A Bad Sign. Time to order a new quad. I like to buy a set anytime I have the do-re-mi so I'll be ready. Which means soon....where's my blasted Visa card? {I keep it hidden - HAVE to keep it hidden, or else...