I've had an output tube fail in a guitar amp (around 1967) with zero damage, and have also had a SS amp destroy a pile of speakers in a large keyboard rig because the preamp was turned off before the amp (back when we used too much stuff on stage). I have also had a Philips JAN 12AT7 fail in my Jolida with no damage (I saw it failing so I could turn the amp off) to anything, and "thetubestore" replaced both 12AT7s under warranty. I now run NOS Mullards in the AT7 spots. |
Hi Milpay, "I have NEVER been in the tubeland" - that's where I was also, some years ago, but things have changed. To my ears tubed gear often sounds better. Now I have a pure tube chain. I am trying out a kind of hybrid preamp, a tube preamp with solid-state power supplies, the Einstein The Tube mk2. I found it used for a good price. It matches my Atma MA-1 OTL tube monoblocs well, and might be very good also in your context (see forum thread 1397501648). It seems very hassle-free, so far. You can roll just 3 tubes to get the sound you want for your favorite input. |
I have never never witnessed, either personally or among the many friends with tube gear, a failure of tube gear that lead to damage of a speaker. Most tube failures end in distortion or no sound from the speaker. In a post above, someone mentioned problems with DC being sent to the speaker; this is impossible with most tube gear because an output transformer CANNOT output DC--DC in the primary would mean no output from the secondary because a fluctuating magnetic field (not DC) is required to induce a current in the secondary. The only possible DC from a tube amp would involve an OTL that does not employ a protection circuit or a blocking capacitor, and I have been told that that failure mode does not happen much either. I suppose that ANY high powered amp, tube or solid state, has the potential to do damage from a failure or operator error causing high level noise to be passed into the speaker.
On the other hand, I have been witness to a few solid state "failures" that did do in speaker drivers. Most often this was caused by operator error (e.g., accidentally pulling an interconnect from a source component causing a LOUD pop). I have also witnessed damage from just plain old abuse of playing at excessive volume--much more common with solid state gear because high power from solid state is "cheaper" and more common.
Owning tube gear might mean a bit more effort is required to maintain top working order--testing and replacing tubes, cleaning tube sockets--but, damage to speakers IS NOT one of those concerns. I would be MUCH more nervous if I owned high-powered solid state gear because of either failure or other conditions that can cause very loud noise, such as power outages/fluctuations (I've heard near heart stopping thumps from solid state gear when power flickered off and on because of crappy service in my area). |
Milpai, tube preamps (unlike tube power amps) require no biasing when tube changes are needed. If the tubes get noisy you can easily replace them, the old ones are lifted out and the new ones just slide in. Generally speaking the low level tubes used in preamps can last for years without needing replacement, but of course an early tube failure is always a possibility. |
Thank You for explaining folks. I have NEVER been in the tubeland. At this point I am seriously considering upgrading my preamp to the Parasound JC-2, because my amp is also Parasoud, and I have heard nothing but good stuff about the combo.
But for the past week, I have been trying to read up on tubed preamps. Still I hesitate to venture into that area because I have no idea about installing, biasing, maintaining tubed components. I will look up more before settling down for a good preamp upgrade. |
I use a Mapletree 2A SE tube stage with my Jolida 502 P and I am very happy with the sound I'm getting (Speakers are Magneplanars 1.7). I have tried the Jolida with a Creek pasive preamp and an Emotiva USP 1 solid state. With these choices, easy win for the Mapletree. Solid bass, great midrange, warm tonality and just as quiet as when using the Creek or the Emotiva. |
IT can happen anytime.
Amp will amplify whatever it is fed unless protection circuitry kicks in.
Tubes can have various issues. So can transistors. But tubes probably more often.
End result will vary case by case depending on circumstance and design.
So tubes are riskier, but not a big problem normally in well designed gear and with good quality tubes. |
There is very little danger of a tube preamp failure causing a large signal that would take out a speaker, particularly when the downstream amp is a low to medium powered tube amp. Damage is more likely with a solid state amp, particularly higher powered amps.
Tube linestages can be a bit more prone to non-life threatening noise issues than a solid state linestage, but, most of such issues can be cured rather easily by changing noisy tubes. As far as life expectancy is concerned, this is largely a matter of the design of the linestage. Most small signal tubes used in linestages have long expected lives and are usually run conservatively and will last a long time. However, there are some designs, such as those by Counterpoint and Audible Illusions that were run somewhat hot and needed relatively frequent tube changes.
I generally prefer an all-tube setup to one that is a hybrid. But, I have run solid state into tubes with pretty decent results. I have generally found the alternative hybrid setup--tube linestage into solid state amp--to be less predictable and consistent in result; it can work, but, there is a greater chance of the combination being a disappointment. |
Hi Newbee,
I agree that a failure of either a tube or solid state preamp can conceivably destroy speakers. DC won't destroy tweeters, though, since the crossover network in the speaker would route it to the lowest frequency driver(s). Unless, that is, its onset is extremely fast, and it is extremely large, in which case I suppose it is possible that a transient at the instant of that onset could be fast enough and large enough to be routed to the tweeters and cause damage in that instant. But that seems very unlikely.
Also, most tube preamps will not be able to output DC since most of them have coupling capacitors at their outputs, and most of those that don't have coupling capacitors have transformer coupled outputs or some other means of DC protection instead.
A relevant anecdote: A few years ago I was listening to my system just after installing the VAC tube power amp I still use, which came with a brand new set of Chinese tubes. After about two hours of beautiful music-making, from one second to the next a huge outburst of continuous static suddenly erupted in one channel. I had the amp shut down within about four seconds, with no secondary damage occurring to either the speakers or the amp. I subsequently determined that a 6SN7 small signal tube in the amp had developed a short. It does seem very conceivable to me that that kind of high volume static, which an output transformer would (and in this case did) pass pretty much unimpeded, could destroy the tweeters in some speakers, especially if the user was not nearby and able to shut things down promptly. And depending also on the power capability of the amp.
In that case, as I say, the problem was a small signal tube in the amp, but the same thing could happen just as easily in a preamp.
In general I would agree with Schubert that the chances of a solid state preamp causing damage can be expected to be significantly lower vs. a tube preamp, but I have no particular feel for how much lower.
Best,
-- Al
|
FWIW I think Schubert might mean that if a tube pre-amp malfunctions and outputs DC that it can cause the loss of a tweeter IF you are running a SS amp which can pass DC, or, perhaps, a transformerless tubed amp. But a SS pre-amp can pass DC so it is really a draw. It is highly unlikely to impossible if using a tubed amp with transformers or a SS amp which has built in protection.
Almarg, comments? Schubert, care to explain in detail?
Milpai, tubes in a pre can last anywhere from 2000 to 10000 hours depending on design and expectations. I agree with Yogiboy. |
Tube preamp and SS amp is one way to go about it..
I have not yet done tube amps... if a tube fails - does the speaker generally go with it as well? |
Milpai,
A tube preamp will not take out speakers if a tube fails.
A tube preamp has low output tubes and they last for years.
Just more audiophile paranoia! BTW there is no maintenance
required. |
Schubert,
Can you please explain what that means? I do not know much about tubes - honest. In a tubed preamp - how long do the tubes last? What is required for maintenance?
Thanks! |
Tube pre's are great, until a tube fails and takes 10K worth of speaker with it. |
Hi again Al2214
Another you can do is keep your existing preamp and add a tube source to your system. I've added a Pro-Ject Tube Box 2 phono preamp and a Eastern Electric Minimax DAC to the system with the Jolida 502P and it has been a positive experience so far. |
If you have a tube amp it makes sense to have a tube preamp. The usual route most go is the opposite of what you have,tube preamp and solid state power amp. Go with tubes all the way! |
Solid state is like a well done hamburger, not juicy, hard textured, not as flavorful, but certainly safer.
Spring for the tube preamp. |
Tried both several times and I'm going back to the Cary 05 tube pre.
Just can't live without tubes. |
Only way to know for sure is to try.
My own perspective is to keep things neutral and tubes to the minimum accordingly. A few tubes + clean and neutral otherwise = the best soup I find.
OF course tube gear can be very neutral as well, but gotta choose carefully and might cost a premium. To date, I've found that like any good thing, tubes can be overdone.
If you have a good tube amp and speakers to match, I personally would not feel the need for more, but that's just me. |
I actually have the same Jolida amp and the Kavent S33 preamp like the wolf man has. The Jolida 502P has matches up really well with the Kavent S33 preamp as well as a vintage Accuphase C200 preamp I have in my main system. Both are solid state. I did try the Jolida with a budget tube preamp. It was a Grant Fidelity DAC-09 that had a tube output and a volume control. The sound was somewhat impacted by the DAC-09. Depending on the tubes I used in the DAC-09 I got a slight bump in the mid-range. With getting a tube preamp and/or DAC the tube rolling combinations would get maddening.
I say keep things as is if you are find the combination enjoyable. If it isn't broke try not to fix it. Tweaking can be a money losing effort for you. |
I have the same Jolida amp. Love it. I feel that the cleanest preamp you can buy of any type is the way to go...I use a balanced dual mono Kavent (re-badged Vincent) because I like having XLRs out to the amp and very quiet sources, but that's just me. If I had a tubed preamp I'd be fiddling with the tubes all the time and the tubed preamps I find attractive are very expensive (reference ARC, Cary SLP 05), and for me the amp tubes provide enough rolling fun. |
