I need to know something....

[Julia]

Is it just me or do power tubes just plain suck? First I noticed the tone had become sucktastic. Then I ended up with a redplate. It actually went orange.

I just had another quad fail. 92 days. Groove Tube 6L6 GE clear tops. Dead in the water -- this time on power tube V3 from left to right.

I seem to go through quads every three months and it doesn't matter brand or what. It doesn't matter what amp either. I think part of the problem is that I'm not running my master at 9:00 am, or what would be bedroom volume.

Well, the tube dealer just gave me a trio (I'll have to get a fourth somewhere) of GT 6550Cs. Someone took out a tube about 15 years ago and dropped it -- it had been a matched quad, and they've had them forever. So at least I got a useable pair free.

so.... does anyone else have this problem? Do the new tubes just suck this bad?

Oh and it doesn't matter if a pro does the biasing. They still go out in a little over three months.

I've had my electric power tested. It's fine. It's not noisy. It's just fine.

I could probably spend a grand on a voltage regulator and power conditioner and still have the same problem.

ARRRGGHHH!!!! this is so frustrating.

 

[kylendm]

Maybe you have a problem in your amp. I've been running JJ 6L6s for almost a year in mine.

 

[KillTone]

I have been following your ongoing tube problems through the forum and find them disturbing. You sound like a knowledgeable, reasonable and more than competent person so there is no reason to assume you are doing something wrong. Maybe you just have bad luck in the tube department?

My experience with tubes has been nothing but good overall. I have gigged with about 10 different tube amps for over 20 years and the only tube failure I have ever had was a EH pre-amp tube burn up in my Mark IV. Before I learned anything about tubes I ran some of them for many years without changing them (both pre and power) and still never had a problem. Other players I have worked with have had similar experiences.

I am not trying to make you jealous with my good experiences, but I am just trying to show that there is hope.

Any input from some of our more savvy posters? Pete? Salvation? Jaded?

 

[Julia]

I seriously doubt it's the amp. I've had trouble like this with three tube amps. They just eat tubes. This tube blew on the side opposite the last tube failure. I had a Marshall JVM that was an absolute nightmare because you had to pull the amp out of the chassis just to check the bias.

I've watched a professional amp tech go through 4 matched quads of Ruby's during one session on an amp, and eventually had to test and find a quad that worked from a those four sets.

For tubes I think I'm just going to get the cheapest stuff out there from here on since they don't last anyway. Or bail on tube power altogether.

If this continues I'll just grab a Crown SS power amp and run the preamp out from the Lynch Box. Will it hurt the transformer to pull the fuses across the board on the power tubes and just not run the power section? I don't have the money for an RM4 AND a Crown SS power amp. I'm figuring I might as well bite the bullet and go SS and at least run tube preamps since this is costing me about $400 - 500 per year just in tubes.

I could also go Tech 21 on the power amp. Who makes a good reliable SS power amp? I'm really getting sick of tubes.

 

[SacredGroove]

At the very least, I'd say you're very unlucky...LOL I've never read nor heard of the problems you've had, with 3 different amps. Maybe all 3 amps were bad? Maybe you keep getting bad tubes? Something is wrong for sure. I never had problems like that with tube amps I've owned. :shock:

A Crown SS amp won't do you any favors either.

 

[Julia]

If all the amps are bad, this means that they can't make amps.... or they can't make tubes. Or both. I seriously doubt it's the amp. The problem is moving around. It's not on the same side, like it was on my JVM. If it was the main bias feed it would affect all the power tubes. I'll stick a spare tube that wasn't screwing up in that slot and see if it runs away. If it does I've got a bad screen grid and the amp will have to go in for warranty work. If not, it was the tube.

the only amp that hasn't given me grief to date (and it could start any time) is my 5150 II. Of course it's a Peavey, and they're made to work after they've fallen off the back of a pickup truck.

So .... back to the last comment.... and I know it goes against the grain here, but after my current stock of power tubes runs out, unless they last longer than 6 months each, I'm done. in that case I'm thinking that with a solid state power amp at least I won't have to worry constantly about tube failure. They may not sound as warm, but screw that. I do know how to operate a 31 band rack mount EQ and roll off everything over 8 kHz.

So who makes a good one? I'd be using the Lynch Box like the RM4 and bypassing the power section.

 

[tehuk]

The ones made by Carvin are very popular. I haven't tried them but everyone seems to use them with their AxeFx rig.

I would suggest trying a power conditioner first though. I play guitar 4 hours every day and my RT2 still has the same EL34s(I switched the 6L6s for KT88s).

 

[Jaded Faith]

I too have been quietly following your posts. In three years with the MTS stuff, I have had 3 tubes go bad. Two were when I first came to the family and set my meter wrong as biased them as hot as the sun and the other was a EH KT88 that gave me a good 1-1.5 years of solid gigging and practicing without fail. Since I live in the Northeast (cold winters) and are an original band, we often play shows with 2-3 other bands and the gear is loaded in and out quickly with only a few minutes on standby before the set and almost no cool down time afterwards before having get it off stage. So I should go through tubes about once a year.

My other guitarist is playing a Peavey Classic 100 head and it has the stock tubes in it from day 1. They are easily 10-15 years old and get used as often as mine in the same conditions. He is also less gentle with his gear.....

My point is, there has to be something not being considered that could explain your problems. These amps can be and often are much more reliable than your experiences have shown. You should not be having ahlf the headachesyou do. I wish I could come up with an idea why this early, but my coffee is still kicking in.

Do you know the year of your MTS amp?

 

[Julia]

The Lynch Box was built in Nov 2008. That's certain. I'm guessing it's a real crap shoot on tubes. Eurotubes people say they reject about half. I'm guessing beyond that half are still bad. It's been like flipping a coin and I keep getting "tails, you lose."

No one ever seems to have the ones I want in stock, and I end up with something else that they have in stock. Maybe there's a reason they're in stock. I've been wanting SEDs since day one. I can order on line and they get tossed around in shipping by UPS or FedEX (USPS). Or I can get them locally where they get them in quantity. I keep getting the "I'm gonna be putting in an order because I'm low" and they never put in the order.

I guess I'll have to take another chance with shipping on tubes. The nearest Randall service center is only 60 miles but around here that's about a 1 to 3 hr drive each way depending upon traffic and construction schedule. We have two seasons: winter, and construction.

 

[KillTone]

You should be fine with shipped tubes. You cannot have any worse luck than you have had with "local" tubes (they were shipped to the store).

I have been buying all my tubes from The Tube Store or E-bay for the last 5+ years and have had no problems with a few exceptions of preamp tubes that were noisy right out of the box. They replaced them, no questions asked.

BTW: if you like EL34's, the guy at The Tube Store recommended some Svetlana's that sound amazing. I have been gigging with them for about a year and they are doing just fine.

 

[Julia]

Well, I stuck a used 6L6 in the slot to test, and there was no runaway so it's not a screen grid. Just a crap tube.

I'm gonna try a duet of that trio of 6550s in there and see how those work. They were free, but new. And if I like them I'll pick up a single. Maybe stick a couple tubes in the outside pair and pull the fuses just to keep the dust out of the spot the tubes plug into (whatever it's called -- I can't remember -- sometimerz disease).

I called Randall and they told me I've got things set up right. Anyway I dropped another couple hundred on a new power conditioner since I found out that the Furman model 8 I had was basically a rack mount surge protector. I got a Monster Pro 2000 for the floor. I'm reading about 117-118 VAC right now.

Anyway I gotta drive up to Seattle right now.

 

[Zander]

I've been real interested in getting a Randall T2 as a backup. I think the head sounds great and that Randall actually got it right making a 400 watt power amp to make up for crappy sounding solid-state sag when you're diming a 100 watt SS amp.

Of course if you've found that *all* your tube amps are bad and refuse to place any more trust in providence, you could source parts and build out an amp head (as I am slowly doing over time)...

 

[Julia]

I'll be picking up a Matched duet of Ruby 6550C Late Distortion from Doug's Tubes tomorrow -- $65. It's cheaper to do this than to do a single, and that will give me one spare. I'm going late distortion because i don't want any chance of the power section going into distortion. I'll run the GT 6550Rs in V1 and V4 and the Ruby's in V2 and V3.

Basically if I want to run my two 212 cabs I need a quad of tubes since they're 8 ohm cabs and i think you half the impedance switch setting when you half the power by pulling two tubes. So if I only run a duet i can only run ONE 212 instead of the normal two 212s. I'm kind of stuck unless I bought four new or used 8 ohm speakers and ran them in series in each cab, or built a parallel to series box to run the cabs in series. either option is either time consuming or expensive.

Looks like I'm back in Peaveyland until next week. funny about this.... I keep ending up back in Peaveyland. is the universe telling me something? the 5150 II is a workhorse.

 

[bruce egnater]

I'm guessing the most trouble you have is with EL34 tubes? We tested hundreds of EL34 tubes primarily for reliability for the Renegade. Basically they all were not good with one exception...the Ruby EL34BHT. They far exceeded all the other brands in their ability to hold up under real world use/abuse. These are what we are using in the Renegade and have virtually no failures yet. FYI, in our opinion (verified by years of building amps and endless testing/evaluation) the Sovtek 5881 is far and away the most reliable power tube ever.

 

[Jaded Faith]

That early 90's Peavey Classic 100 head our other guitarist uses still has the stock tubes in it all around. So I opened it up to see what the hell was in there that lasted so long and wouldn't you know it was Sovtek 12AX7's and EL84's? Cobwebs on them and all (I cleaned it up for him), those tubes never die and still sound great. I'll continue to pray he decides to update them before failure...... :roll:

 

[Julia]

Thanks for poking your head in here, Bruce. Yes over the past couple years most problems have been with EL34s. They were absolutely horrid when I had my Marshall JVM and that amp started eating them for breakfast, lunch and dinner, but that circuit isn't as well protected as the Randall and Egnater stuff. They use 1 amp slo-blo fuses in it. And the amp tech noticed a significant degradation over a period of 6 mos. The first quad lasted 100 days. It was in the shop for two months. The second quad lasted 3 weeks. Then it ate 4 at the shop (all Ruby's), and the tech got one quad to work but the amp sounded like crap so I got a warranty exchange. Enter the LB.

The Lynch Box shipped with JJ E34Ls. Those took a dump after 3 mos. So I wanted to go with SED EL34s from Ruby and ordered them from the local supplier (the amp tech) -- he uses JJs and never ordered them for me. I thought having local support might be helpful. Well it isn't.

So the store where I got the amp sold me a quad of Sovtek 5881s and these failed straight out of the box (platinum tested my patootie) -- this happens -- arced just a couple bad tubes and blew a fuse. They replaced them with another quad, but being without an amp since a friend was borrowing my 5150 I picked up the Groove Tubes 6L6GE cleartops which were in stock locally (not GC). These are the ones that just took a dump. But then these are the new production tubes -- they sounded good while they lasted, but they didn't last.

So I just got off the phone with Doug's Tubes and he's shipping me a quad of Ruby 6550C (=C=) for late distortion for $130. And we'll see how these work out. I'll keep the "New Sensor" Groove Tubes as spares. At least I get a 6 mo warranty on the tubes.

I bias the amp according to the instructive video and set the tubes about center according to the manual.

I'm guessing the most trouble you have is with EL34 tubes? We tested hundreds of EL34 tubes primarily for reliability for the Renegade. Basically they all were not good with one exception...the Ruby EL34BHT. They far exceeded all the other brands in their ability to hold up under real world use/abuse. These are what we are using in the Renegade and have virtually no failures yet. FYI, in our opinion (verified by years of building amps and endless testing/evaluation) the Sovtek 5881 is far and away the most reliable power tube ever.

 

[bruce egnater]

Wow. Your troubles sound really excessive. Seems like your amp does have something else wrong but I could not venture a guess. You are not using an attentuator (HotPlate), are you? Are you absolutely sure your amp impedance switch setting is matched to the speakers? Do you play really loud? Do the tubes typically fail at turn on or only after the amp is on for a while?

 

[kc2eeb]

I have one of the first 5 Kendrick 2410 amplifiers ( One of the first, if not
thee first Fender Bassman re-creations from the early 90's) with the
original Russian 5881s.
The 5881 was and probably still is used in Russian tanks in the tank radios.

 

[indytruckboy]

That early 90's Peavey Classic 100 head our other guitarist uses still has the stock tubes in it all around. So I opened it up to see what the hell was in there that lasted so long and wouldn't you know it was Sovtek 12AX7's and EL84's? Cobwebs on them and all (I cleaned it up for him), those tubes never die and still sound great. I'll continue to pray he decides to update them before failure...... :roll:

My first year 5150 has the original tubes in it :shock: . And I use it for weekly practice and twice a month gigs...........

.....for the last 3 years.



Peavey bias on them is REALLY cold, and that is part of there characteristic sound. So maybe try setting your bias a little lower than what you normally do.

 

[Julia]

I originally set the bias on the 6L6GEs at 34.5 mV. After the tube failure in V3, and when I stuck a 5 yr old single GT 6L6B (survivor of a duet that was in my Fender amp and I think is a 5881) in the V3 slot to test for bias runaway I checked the remaining V1, V2, and V4, and they had drifted DOWN a bit:

V1 was at 31.1
V2 was at 32
V4 was at 31.4

Anyway I'm in communication with someone here and I'll post what we've come up with afterward.

I think a lot of the information here has gotten blurred with the amp I had before this one -- that was a Marshall JVM and I had gotten a lemon (and Korg in NY where we sent the amp agreed). The store where I got it gave me a warranty exchange to get the Lynch Box.

It is difficult to diagnose in a forum.