Tube Amps for Dummies

[Bernard]

...........The final type requires you to measure the current across the tubes load resistor which does expose one to the lethal voltages (>500v) inside a tube amp. Be careful with these types as they can kill you.........

Care is something that cannot be stressed enough. In the ARC monoblocks I have the load resistor is placed in a very awkward position, and the first couple of time I inserted test clips to measure the bias voltage I got zapped even though I was very careful. I now insert the test clips BEFORE I power on the amp. It is educational BTW to see how long it takes for the bias voltage to come up to the right value, underlining that with tube amps you do not just turn on the power and feed them music right away (true for SS to some extent as well).

 

[risabet]

Care is something that cannot be stressed enough. In the ARC monoblocks I have the load resistor is placed in a very awkward position, and the first couple of time I inserted test clips to measure the bias voltage I got zapped even though I was very careful. I now insert the test clips BEFORE I power on the amp. It is educational BTW to see how long it takes for the bias voltage to come up to the right value, underlining that with tube amps you do not just turn on the power and feed them music right away (true for SS to some extent as well).

Why does a manufacturer like ARC continue to put the lives of its customers at stake when placing bias taps in a safe place is so damned easy and inexpensive.

Once when working on a TV in an electronics class I failed to discharge a rather large capacitor and nearly blew myself across the room when I shorted it out. I shook for about 20 minutes. I never made that mistake again.

 

[nsgarch]

Why does a manufacturer like ARC continue to put the lives of its customers at stake when placing bias taps in a safe place is so damned easy and inexpensive. Once when working on a TV in an electronics class I failed to discharge a rather large capacitor and nearly blew myself across the room when I shorted it out. I shook for about 20 minutes. I never made that mistake again.

WOW, an ARC tee vee? COOL!!

 

[risabet]

WOW, an ARC tee vee? COOL!!

Notice the new paragraph

 

[slowGEEZR]

"Tubes sound better" ????? A VERY VERY subjective statement with no truth to it at all, just someones opinion. Again, either you like the sound of tubes or you do not.

How true! When I went to John P.'s listening session in Austin last month (http://www.martinloganowners.com/~tdacquis/forum/showthread.php?t=4948), I was blown away when someone hooked up a huge home made 25 wpc tube amp to his Odysseys. Only 25watts per, and it made those speakers perform. I thought the sound quality took a jump when it replaced the SS amp that was there. (John's main amp is a Classe CA300.) When I talked to John about it, he said something to the effect that he agreed, it sounded good, but when he listens to a tube amp for a period of time and puts his Classe back in, it sounds good then. So, for what it's worth, I believe you have to listen for extended periods before you really know what an amp sounds like. By the way, his preamp was tube and I still heard a difference when the amp was replaced.

 

[Gordon Gray]

Beauty in the eye of the beholder!

How many times have we had this discussion. I admit it is a good discussion. However, IMHO, one needs to listen to the amp, along with everything else, in their room, to make an informed decision as to what is "RIGHT" for that particular individual.

Variables include, but are not limited to:

1) Room size / acoustical issues.

2) Type(s) of music you listen to.

3) How loud or soft you like volume levels.

4) The state of your hearing.

5) How many "sweet spots" you want in your listening environment.

6) Interconnects and speaker cables.

7) Component synergy.

8) Vibration isolation.

9) Speaker placement.

10) Etc., etc.

You all know the drill and I'm sure you can add to the above list.

Bottom line for me, after having been involved in this wonderful hobby for some 30 years, is the following question:

How emotionally involved are you with the music when you listen to your system?

That really is the core of the issue for me regarding the reproduced music coming from your system. Tube vs SS amps or whatever.

No one is correct, because it is totally subjective, and it, the musical listening experience, is entirely dependant on your personal reaction to what you hear.

Then there's your current state of mind, when you are listening, and how the music compliments / enhances your emotional state or doesn't quite fit.

Not to say that better components, whatever that means to the individual, doesn't make a difference. I know, as I have upgraded over the years, that better (read in some cases mean more dollars) does increase one's personal perspective that "you are closer to the music".

Let your heart and soul, along with those silly things on the side of your head, decide what is right or wrong.

GG

 

[Bernard]

..........

Then there's your current state of mind, when you are listening, and how the music compliments / enhances your emotional state or doesn't quite fit.......

To be more succinct - how inebriated you are (hic ! ...or is that sic ! ?)

 

[Bernard]

Why does a manufacturer like ARC continue to put the lives of its customers at stake when placing bias taps in a safe place is so damned easy and inexpensive.

Once when working on a TV in an electronics class I failed to discharge a rather large capacitor and nearly blew myself across the room when I shorted it out. I shook for about 20 minutes. I never made that mistake again.

Yes, indeed, why did ARC do that stupidity ??

I once worked on an amplifier with a power supply capacitor that got spiked on turn-on when there was a reactive load. The stuffing got literally blown out of the capacitor. Makes you appreciate what power amp designers have to contend with.

 

[SundayNiagara]

""Tubes sound better" ?????"

Absolutely correct sir!

 

[Rich]

""Tubes sound better" ?????"

Absolutely correct sir!

Tubes sound Better!!!

No, they don't!!!

Yes, they do!!!


Come on guys, this is not an opinion poll. It's a discussion. And the original poster wasn't even concerned with what sounds better. He was asking about what the maintenance demands of tube amps are.

As for the tube vs. solid state debate, there are tube amps that sound great and tube amps that sound like crap. Just like solid state. In general, most people will prefer one over the other for lots of different reasons, as Gordon enumerated.

I find it interesting that for the past twenty or so years, solid state manufacturers have been trying to get their amps to have a more warm, smooth, "tubelike" sound, while tube manufacturers are trying to get their amps to have a more neutral sound with that solid state bass kick. Everybody wants the best of both worlds. Which is one reason lots of folks biamp with tubes on the panels and solid state on the bass, or why folks run a tube preamp with solid state amps. I personally have done both with great results.

To answer your question, David, there are lots of tube amps / preamps available that require very little maintenance. Expect to have to replace the tubes every couple of years or so, and expect to have to bias them every time you change tubes and about every six months or so. If you buy an auto-biasing amp, you don't even have to do that. With my CJ amp, biasing is a breeze. You just turn a small knob using a supplied tool until an led light goes out and then you move on to the next one.

Rarely does one tube just "blow." Usually the sound just degrades as the tubes age and at some point you realize that it is time to change the tubes and you change all the tubes at once. Changing tubes is also easy -- no need to send it off to be retubed. You can buy tubes directly from the amp manufacturer or from a specialty tube dealer. You can get quality current manufactured tubes reasonably priced or you can get quality New Old Stock (NOS) tubes for an arm and a leg.

Sure, they are a little more work than solid state amps, but not so bad as to keep you from enjoying them. Look at Cherian. He just got one and doesn't seem to be having any issues. My suggestion is to buy one used on A'gon and play with it for awhile and if you don't like it you can probably sell it again with little loss of money.

 

[tonepub]

I've bounced back and forth on this plenty over the years. These days I'm listening to solid state power on my main system with my Summits, but always am plugging in different amps tube and solid state for review.

It really comes down to a flavor thing for you... My guess is the tube thing will grab you or it wont. If it doesn't grab you, stick with SS, it's easier.

Seeing you mentioned being a bit lazy and perhaps interested in some of the tube related rituals, this might help:

How much time per week in hours do you usually get to listen to your system? If you are a very casual listener 2-5 hours a week, it will take a long time for you to rack up 3-5000 hours before you need to worry about replacing tubes. If you listen a lot, say 10-20 hours a week, or even more, that maintenance time will come up a lot faster, which also leads to a more frequent infusion of cash.

Even a decent power amp will have at least 4-8 output tubes to replace. Mileage can vary with the small signal tubes, but again most power amps will have anywhere from 4-12 small signal tubes that you can more than likely replace every other time you replace the power tubes.

Again, all of this can vary, depending on if you buy new, current stock tubes or vintage/NOS (new old stock) tubes. That's a whole nother argument/discussion in itself.

Lets just assume for a second you are getting a fairly standard tube power amplifier with four 6550/KT88 output tubes and four small signal 12AX7/AU7/AT7 tubes. A good rule of thumb is to expect at least 3000 hours out of a set of tubes. Stock Chinese or Russian versions will probably run about $50 per. Figure about 6000 hours for the small signal tubes at about 20 per.

NOS tubes will usually last longer, and in the case of the small signal tubes can last a lot longer, but will cost more money (sometimes 2-5 times more each) and can be a crap shoot. The two best guys I've dealt with are Kevin Deal at Upscale Audio and Andy at Vintage Tube Services. Im sure there are a few others, but I've been buying NOS tubes from both of these guys for almost ten years and that's at least a good place to start.

Good luck!

 

[eknuds01]

Tubes sound Better!!!

No, they don't!!!

Yes, they do!!!


Come on guys, this is not an opinion poll. It's a discussion. And the original poster wasn't even concerned with what sounds better. He was asking about what the maintenance demands of tube amps are.

As for the tube vs. solid state debate, there are tube amps that sound great and tube amps that sound like crap. Just like solid state. In general, most people will prefer one over the other for lots of different reasons, as Gordon enumerated.

I find it interesting that for the past twenty or so years, solid state manufacturers have been trying to get their amps to have a more warm, smooth, "tubelike" sound, while tube manufacturers are trying to get their amps to have a more neutral sound with that solid state bass kick. Everybody wants the best of both worlds. Which is one reason lots of folks biamp with tubes on the panels and solid state on the bass, or why folks run a tube preamp with solid state amps. I personally have done both with great results.

To answer your question, David, there are lots of tube amps / preamps available that require very little maintenance. Expect to have to replace the tubes every couple of years or so, and expect to have to bias them every time you change tubes and about every six months or so. If you buy an auto-biasing amp, you don't even have to do that. With my CJ amp, biasing is a breeze. You just turn a small knob using a supplied tool until an led light goes out and then you move on to the next one.

Rarely does one tube just "blow." Usually the sound just degrades as the tubes age and at some point you realize that it is time to change the tubes and you change all the tubes at once. Changing tubes is also easy -- no need to send it off to be retubed. You can buy tubes directly from the amp manufacturer or from a specialty tube dealer. You can get quality current manufactured tubes reasonably priced or you can get quality New Old Stock (NOS) tubes for an arm and a leg.

Sure, they are a little more work than solid state amps, but not so bad as to keep you from enjoying them. Look at Cherian. He just got one and doesn't seem to be having any issues. My suggestion is to buy one used on A'gon and play with it for awhile and if you don't like it you can probably sell it again with little loss of money.

Well said, Rich.

Let me also add to Jeff Z's earlier post. What fun would this hobby be if there was an absolute best (which is not possible anyway) ?

Part of the intrigue of this hobby is the ability to try new things, swap parts around, move furniture all over the place, room treatments, purchase/demo new amps, pre-amps, cables, and speakers. I also enjoy listening to my friend's systems with my favorite music and it's always fun to listen to the subtle differences between the two.

Erik

 

[mrmike]

My experience with tubes is with a very nice preamp. No need to bad mouth the brand but lets just say it is well received and from a small manufacturer.

What I did not not like is that you had to be very careful the order you would turn on your preamp and amp or else you would get a loud pop in the speaker. I never did damage the speaker but I did blow up my home theater proccessor Not sure how tube amps react in this regard but I will probably stay away from tubes from now on.

 

[aliveatfive]

My experience with tubes is with a very nice preamp. No need to bad mouth the brand but lets just say it is well received and from a small manufacturer.

What I did not not like is that you had to be very careful the order you would turn on your preamp and amp or else you would get a loud pop in the speaker. I never did damage the speaker but I did blow up my home theater proccessor Not sure how tube amps react in this regard but I will probably stay away from tubes from now on.

How could you describe that as a "very nice tube preamp"? Obviously it was very flawed. Properly designed preamps mute themselves at turn-on so there will be no pops. BTW - this aberration can occur with solid state pres as well!

 

[risabet]

My experience with tubes is with a very nice preamp. No need to bad mouth the brand but lets just say it is well received and from a small manufacturer.

What I did not not like is that you had to be very careful the order you would turn on your preamp and amp or else you would get a loud pop in the speaker. I never did damage the speaker but I did blow up my home theater proccessor Not sure how tube amps react in this regard but I will probably stay away from tubes from now on.

This isn't uncommon with some tube pres and is easily accommodated with proper sequencing of turn on and turn off. Pre>processor>amps with a pause in between at turn on and the reversed sequence at turn off. That said, a good pre is muted for a few seconds to eliminate this problem. Alive is correct in that SS pres can have this problem also.

 

[nsgarch]

What I did not not like is that you had to be very careful the order you would turn on your preamp and amp or else you would get a loud pop in the speaker. I never did damage the speaker but I did blow up my home theater proccessor Not sure how tube amps react in this regard but I will probably stay away from tubes from now on.

One of the customary (if not Cardinal) rules of audio is that the amp is turned on last, and turned off first.

How could you describe that as a "very nice tube preamp"? Obviously it was very flawed. Properly designed preamps mute themselves at turn-on so there will be no pops. BTW - this aberration can occur with solid state pres as well!

Furthermore, most fine preamps customarily do not employ muting circuits. Why? Because although a simple muting shunt will not add noise to the signal, a shunt with a timing circuit can add noise to the power supply unless it has it's own.

 

[mrmike]

Maybe it has nothing to do with the tubes at all. All I know is that I don't have that problem using my home theater proccessor as my preamp.

I would like to try a tube amp sometime if I was convinced it was easy and safe to use.

 

[abhijit]

How is EAR 890 with Summit and Cary SLP-05?

 

[risabet]

Maybe it has nothing to do with the tubes at all. All I know is that I don't have that problem using my home theater proccessor as my preamp.

I would like to try a tube amp sometime if I was convinced it was easy and safe to use.

Try a Prima Luna amp, maybe their mono Prologue Sevens @ 70wpc as these will be both easy and safe and sound good too.

 

[SundayNiagara]

"there are tube amps that sound great and tube amps that sound like crap."

If the latter happens, get speakers that are easier to drive and you will be rewarded with much musical pleasure.