I'm curious to know if manufacturers test the tubes that they use in the amplifiers before they ship them out? Maybe they test fine and then go bad within a month. I'm very suspicious they don't bother testing their tubes.
@emergingsoul They definitely test them! But there is not a good way to really know how long a tube will last, especially now in the twilight era of tube amplifiers.
Usually a tube amp producer will have a warranty on the tubes, which is usually 90 days. We do a year but that's unusual. So if you've had this amp less than 90 days I'd simply get a replacement tubes. If you own a tube amplifier its a good idea to have spares on hand. You can use a spare to help you sort out which tube is giving you trouble.
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Audio Research extensively tests all their tubes. They have a huge room bristling with tubes being tested. I have never received a bad tube from them.
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Funny with the amount of tube amplifiers I see at shows I hardly see this as the product being in it's twilight. JJ tubes maybe of questionable quality, or filaments maybe getting damaged in shipping?
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Avoid the JJ`s.
Look to a reputable Dealer.
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@audio_is_subjective "...or filaments maybe getting damaged in shipping?".
Possibly so. No joke. I had a particular 6SN7 tube I was buying from a specific distributor overseas who densely cotton packed, bubble wrapped, and then double boxed quad sets I was buying. No problems for me on any of them, shipped from over seas to me direct. Many drop changes too, along the way. Others, were having issues with the exact same tubes. Nobody could figure out what was going on. They chased it down. Took a while for the manufacturer to figure it out.
Two years later they figured out they were shipping these large boxes of 100 units (or so) well packed, to a US Distributors who was taking them out of those specially packed boxes, and poorly repacking them in other cheap packaging as individual or pairs and sending them out. All the sudden this distribution channel had problems. People blamed the tubes themselves, and yet it was poor re-packing and shipping damage occurring. Recalling photos, the US distributor put NO time, care, $, or effort into the repackaging and boxing. THIS created a real problem for the reputation of the manufacturer. Was unfortunate, this created other business issues too.
ASK:
Ask your tube reseller to explain exactly how they get shipped out or send you a few photos before shipping them out. If they won’t do this, move to a different tube reseller. Best of Luck!
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I had a preamp JJ 6922 go bad at about 100 hours. Heard a crackling and then the left channel went silent. Popped the top on the preamp and the top of the tube was completely burned out. When I went to pull the tube the glass completely disintegrated.
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Tubes are a consummable. use this as an opportunity to upgrade.
PS I wouldn't own an amp with 24 tubes.
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If they are preamp tubes, they should last 2000-10000 hours depending on the design of the preamp. Obviously there is something wrong. While I don’t particularly like the sound of JJ tubes, they might not be at fault and I would hope Mac would inspect the tubes they buy before they install or send them out.
Did you buy the amp new from a dealer? Maybe it needs someone to check it out?
All the best.
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I have used JJ tubes for the past 7 years, in my case re-branded tubes with the McIntosh logo on them. The 12ax7 tubes are quieter than the 2 Gold Lion 12ax7 tubes I am using in the line stage. This weekend I will swap out the Gold Lions for 2 McIntosh (JJ) tubes. I have no such problems with them and never have. The McIntosh tubes were purchased from Audio Classics.
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Popped the top on the preamp and the top of the tube was completely burned out. When I went to pull the tube the glass completely disintegrated.
I had a pair of 6550 (output) tubes (in an amp) redplate for way longer than I ever should have let them, and nothing like that happened. I'd like to see that 6922, @samzx12 , pics?
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I have used JJ tubes for the past 7 years, in my case re-branded tubes with the McIntosh logo on them. The 12ax7 tubes are quieter than the 2 Gold Lion 12ax7 tubes I am using in the line stage. This weekend I will swap out the Gold Lions for 2 McIntosh (JJ) tubes. I have no such problems with them and never have.
@stereo5 , I am using a quad of JJ (first time with JJs for me) 6SN7s in a SLP05, and the reason I went with JJs was because a friend of mine related basically the same as you did. So far I have no problem with them.
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@immatthewj I didn't take a picture after pulling out the tube.
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Those are crappy cheap tubes, buy a quality New Old Stockthe real deal
call either vintage tube services ,brent Jesse recording
the original tubes last longer and sound better
brent Jesse ever offers for a $30-40 extra a two year. Warranty peach brand sounds different , nos tubes were built to a much higher standard.
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There's nothing particularly bad about JJs - they are extensively used in the front end of guitar amplifiers that get a much harder life than hi fi. It's relatively unusual for small signal tubes to fail early in their life, but it does occasionally happen.
@OP - it's not guaranteed that it's the tubes that are at fault. It could be a dry joint on a tube base, for example.
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Yes they do test them but current tubes aren’t what they used to be quality wise. McIntosh is very easy on tubes, so the problem is definitely the JJs. That’s why I use NOS. I use Amprex Medical 12 ax7 s in my C2300 and have well over 10000 hours. I would look into those or NOS Telefunkens. I think you’d be very happy both quality wise and sonically.
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JJ's are mediocre tubes at best. For best sound and reliability, get some nos from a reputable dealer.
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Repeated problem: I am highly suspicious of the AMP, not the tubes.
TUBES: A simple tube tester puts you in control, without one, it’s a confusing mess.
test single and matched sets you buy, test periodically, test when problems occur.
Have Spares, but they should last many thousands of hours.
Many are on eBay etc.
Keep your eye out for a decent tester that seller says works, and accepts returns.
I have the smaller model 157, I would get this model 257 if I did not have one. I got a 257 for a friend, he loves it.
seller: 100% positive rating: 30 day returns:
read full description and ’watch video’
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Until you get your amp checked out by a reputable technician, all these comments are guesses at best. Blaming the JJ tubes might be correct, or not. As many have noted, poor shipping, handling, and such can damage any tube, even NOS.
JJ tubes are treated roughly in guitar amps and don't fail very quickly. I have used them in a Schiit headphone amp to good effect (6922). Sure, NOS might sound better, but if we want this hobby to continue with vacuum tubes or "valves" as they are called in Europe, then we have to be looking at new production tubes because the supply of vintage tubes will run out one day. What do you do then, move to Class D with Hypex or PuriFi chips?
Perhaps replace the JJ tubes with something else and see if they too get fried. If not, then you'll sort of know it might have been "something unquantifiable" with the JJ. But if they too get fried early on, then you definitely should get the amp looked at. Nothing made by humans is 100% perfect or as intended 100% of the time. Just the reality of manufactured goods.
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in my new mac gear the JJ's were the first to go they sound flat, bright, toneless compared to better tubes, specially some nice NOS tubes. first thing is to upgrade those small signal tubes asap. yup I get it I also have a mac preamp and power amp all tubes and yup there is a lot of them. start with the small signal tubes.
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Funny with the amount of tube amplifiers I see at shows I hardly see this as the product being in it’s twilight. JJ tubes maybe of questionable quality, or filaments maybe getting damaged in shipping?
@audio_is_subjective I used that phrase because there are class D amps out there that rival tubes in every way except grace at clipping. The guitar market is the primary market of tube producers; high end audio is a tiny portion of their market. These days many guitar players rely on their effects pedals to get their ’sound’ so the amp only has to be smooth enough (not grating) and otherwise similar limited bandwidth of conventional guitar amps (unless one is talking about a Marshall Major or Ampeg V4, which are built on hifi standards).
Tube guitar amps weigh a lot! At 3:AM in the morning after playing a gig, it makes a difference if the amp weighs 85 pounds or only 15. Now that there are musical class D guitar amps out there its simply a matter of time that they will invade the market more and more since they are more reliable with no change to the ’sound’ that players are looking for. So in ten years the guitar market will look quite different. That means that the major market of tube producers is shrinking and nothing to do with the war in Ukraine or what high end audio is up to.
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@atmasphere I understand your position and I am not a GaN naysayer. I also do not see the death of tube amplification coming nearly as fast as you do.
When I was in grade 6 I had a science teacher teaching the Evolution Module state that at some point humans would only have 4 toes, as our little toe will simply devolve from our anatomy as humans will walk less in the future and stand less with automation. I agree she was a bit daft. Though I am still waiting for that hover board and flying car she said we would have by Y2K.....
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@glennewdick , perfect description of JJs. I’m absolutely with you, they sound pretty bad.
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I had a preamp JJ 6922 go bad at about 100 hours. Heard a crackling and then the left channel went silent. Popped the top on the preamp and the top of the tube was completely burned out. When I went to pull the tube the glass completely disintegrated.
@samzx12 , that is interesting. I've had power tubes actually short out before and all that ever happened was that a fuse in the amp blew . . . you are saying that a fuse in your preamp practically caught fire (almost) and no circuit protection device tripped?
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@immatthewj no I didn’t say it practically caught fire. The tube went bad and the top of the tube was very discolored and when i went to pull it out the glass crumbled. I sent you a PM.
I replaced both tubes left and right channels and preamp plays just fine.
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Popped the top on the preamp and the top of the tube was completely burned out.
Sorry if I misinterpreted that, @samzx12 , when I initially read that it just sounded almost catastrophic was all, and I was thinking that it must have been a lot of current to do something like that. No biggy though--I was just curious.
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@atmasphere - it's even worse than that because guitarists are switching to modelling systems which include cab simulation so that they can ditch their amps altogether.
As far as I'm concerned these systems and class D amp's are very far away from the real thing but, as you say, convenience is driving the market and it will undoubtedly affect tube sales.
I can't see us running out of 12AX7s, EL84/34s or equivalent any time soon but non guitar amp tubes could get scarce.
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I have heard that equipment manufacturers use JJ's because they last longer. I am not sure if its's true but my Luxman had JJ's with the Luxman branding. I will have to say that they do not sound good. I replaced them and it was a huge upgrade. You should try some RCA clear tops (12AU7) (low cost) or some Mullard or Telefunken (12AX7 OR 12AT7) if you don't mind paying more. Some of the new ones are pretty good and cheaper Than NOS.
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I've never heard a current production small signal tube (especially JJ) that wasn't beaten by some NOS stuff. Immediate and obvious improvement in sound, and the added benefit of longevity Check out Brent Jesse. Knowledgeable, reasonable and reliable.
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I recently had a relatively new (about few dozen hours) JJ 6922 gold pin in my preamp went "pop!" then died with the glass badly cracked near the base. Thankfully I was still able to remove the dead tube from its socket.
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I recently had a relatively new (about few dozen hours) JJ 6922 gold pin in my preamp went "pop!" then died with the glass badly cracked near the base.
Wow--sounds like an epidemic! Pics?
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JJ’s have proven to be the most unreliable and poorest sounding tubes I’ve used in any of my tube electronics. ymmv. “Twilight era of tube amps”. I guess only time will tell. My money is on tubes.
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Telefunken, RCA, Mazda, Gold Lion, lots of other choices, may cost a little but what did the FRAM man say?? Pay me now or pay me later? (Fram filters do suck though)
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The vast majority of small signal triodes are made by either JJ or New Sensor - regardless of what name is on the box.
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JJ tubes are so so at best....
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