Why are tube amps better? (1 Viewer)

[Ryan Cruz]

Or are they not always better?

 

[KeithH]

Ryan, like anything, I don't think you will find that all people prefer tubes. Those that do often say that tubes give a warmer, more natural sound than solid-state components. I have limited experience with tube amps and pre-amps, but I will be setting up my parents' vintage Marantz tube separates in my main stereo system in the near future. It is my hope that I will experience what many others have with tubes in relation to solid-state gear. I am current using an NAD solid-state set-up (C 370 integrated amp biamped with a C 270 power amp). To my ears, the NAD gear sounds great, but the Marantz tube components should be better.

 

[Robert_Dufresne]

Keith
I was looking at the pictures of your equipment and I
noticed a Denon 370 CD changer.
I am looking to buy one for myself so I would like
to know if you like it.
Sorry if this is not related to thread.
Robert

 

[Steve Zimmerman]

It is my opinion that there are psychological reasons for preferring one type of sound over another. I recently read a review of a very expensive tube preamp in which their very famous and highly-pedigreed designers are decidedly NOT fans of tubes. The irony of their stated goal (which was "to make a tube preamp and have it be as good as solid state") was apparently lost on the reviewer.

Based on the stuff on display at CES this last year, it's my opinion that we are in something of a renaissance period in audio--in much the same way that modern fly fishermen have lately become enamored of using antique-style rods made of bamboo instead of modern graphite and carbon-fibre.

I have a hard time believing that all these professional engineers that have spent their entire lives designing equipment are just now suddenly seeing the light and realizing that OH MY GOSH we've been deluding ourselves these last 30 years and tubes really are better.

I'm of the opinion that it's more than just the sound of tubes that is driving the craze.

I'm not saying that some people don't/won't like the sound. If you like tubes that's great. Some people like bellbottoms and platform shoes.

--Steve

 

[Arthur S]

Ryan

Tube amps are said to generate more even order(2,4,6,8 etc) harmonics than odd order (3,5,7,9). Even order harmonics are more ear friendly than odd order harmonics. Tubes also have a tendency to roll off at the top and bottom of the sound spectrum, thus resulting in less bright sound.

There is also a group of people who swear by tubes. Some of these folks will use a 3 watt tube amp. The design is called single ended triode (SET), and these folks will drive speakers that would usually be considered to need, say, 50-100 watts or more. But they say they love the sound from 3 watt SET.

There is no discussion that will change their minds. Good chance they are "enjoying" all that even order harmonic distortion. Such distortion is said to be Euphonic or a pleasing sound to the ear.

For the majority of folks interested in tubes, the compromise they will often come up with is a tube pre-amp and a solid state amp, or an amp with 1 tube and the rest solid state.

Cost is a big factor with tubes. For the cost of a 25 watt tube amp you can easily get a 125 watt solid state.

There are lost of issues with tubes such as mechanical harmonics, wear, which brand and specific choice of tube, and much more.

Those with the resources will sometimes buy exotic super high efficiency speakers so they can use the 3 watt SET.

Most of us don't have the money for such things.

Before your time, a fairly famous amp designer named Bob Carver, made a challenge ($10,000?) that he could modify his solid state amp to sound exactly like any tube amp. I believe Bob still has his $10,000. He also makes some solid state amps that give you the choice of solid state or tube type sound via connections on the back so people fascinated with tubes can have it both ways.

Artie

 

[Arnel Enero]

For my tastes, at least, tubes are most of the time NOT better that solid-state. I'm not willing to sacrifice ultimate treble and bass extension, macro-dynamics and transparency just for a little bit extra warmth and harmonic richness (a.k.a. euphonic distortion product).

Sorry but to me, tube = boring romantic. I don't even remember hearing any tube amp that rocks, the big VTL stuff included. Solid-state amp technology has been improving significantly, surpassing its early shortcomings. So I don't see any reason FOR ME to go back to the technology of my father's teenage years, kinda like leaping backwards. Well, I'm speaking only for myself and I respect all tube-o-philes.

 

[Saurav]

Well, I've been using tubes in my system for a few months now, and I find the sound more to my liking than when I had solid state.

Or are they not always better?

Depends on your speakers. If they're not very efficient, or have wide impedance/phase swings, tube amps will have a hard time driving them, and it will show in the sound.
If you want to just try out tubes, investigate tube preamplifiers. That gets you some of the sound, without having to worry about the speaker matching issues.
And finally, it's all in the sound. If you like to go by specifications, stick to SS, because tube amps have much worse noise and distortion numbers than SS amps. However, if you listen to your equipment instead of measuring it, try out tubes

 

[Saurav]

I'm not willing to sacrifice ultimate treble and bass extension, macro-dynamics and transparency just for a little bit extra warmth and harmonic richness (a.k.a. euphonic distortion product).

I agree, it all comes down to a person's taste in sound.
Edit: Speaking of a tube amp's ability to rock - if you think about it, rock music was born from tube amps and horn speakers

 

[Saurav]

One more post to wrap it up. IMO, there are good implementations of tube amps, and there are bad ones. Just as there are good and bad implementations of SS amps. When it's done right, both SS and tubes can sound excellent. Both have their strengths and weaknesses, and matching the associated equipment is always important. So, in the end, assuming everything else is ideally set up, it usually comes down to a matter of taste and personal choice. I happen to prefer tubes, because my priorities lean towards the aspects of reproducing music that I think tubes do better than SS. Other people will obviously have different tastes, which will lead them to different equipment choices. There's no right or wrong here.
Note: No disparaging remarks about, or comparisions with, people who wear bell-bottoms and platform shoes

 

[chung]

There is a fairly technical article on tubes vs transistors here:
http://www.trueaudio.com/at_eetjlm.htm
If you do a Google search on tubes vs transistors, you will find lots of threads covering this topic.
Several things that I would like to point out that are sometimes misunderstood IMO:
1. Push-pull tube amps do not create any less odd-harmonic distortion than SS, unless they are in clipping already. A balanced topology always has much fewer even-ordered distortion, regardless of whether SS or tubes. It is only the single-end designs that tend to generate even-ordered distortion products. SET's are either notorious or famous in this regard, depending on your point of view. BTW, SET's generate odd-harmonics also. Some may like even harmonics, but do keep in mind that the same non-linearity that gives rise to even harmonics also results in intermodulation products which are decidedly not musical. The old Mac's and Marantz's are not SET's.
2. When operating below clipping, good push-pull tube amps sound very similar to solid states. SET's sound different because of the higher distortion, but more significantly I believe, because of the high output resistance. The high output resistance can make the overall frequency response not flat if the speaker does not present a constant resistive load over frequency. I think this coloring is a big part of what makes SET's sound so different. Some people call it warmth. The output transformer also adds its own "sonic signature".
3. A solid-state watt is the same as a tube watt. One should always operate the power amp below clipping. In a solid state design, the goal is to reproduce audio as faithfully as possible, and therefore, to maintain linearity over as big an output level as possible. In an SET, non-linearity starts very early. Sure, the clipping is more gradual, but does one want to see the onset of non-linearity so early?
4. It is easier to design a good SS amp at low power than at high power. Those highly efficient speakers can sound equally good (for those who like their sound) when driven by low-power high quality SS amps.
5. The SET's have a lot more variation in performance than solid-state gear. In the same design, a tube from a different batch may produce a different sound, and the exact operating point is a very crucial adjustment. Tubes also age, with a corresponding change in sound. This also tells you the kind of accuracy one can expect from SET's.
It is highly personal whether one likes the sound of tubes, especially SET's, or solid-state. If one desires flat frequency response and low distortion, SET's probably should be avoided. There are good push-pull tube amps, though, that compare with the best SS gear in accuracy, when operated within their designed output range.
At any given price point, solid state amps will give you a better value in terms of output power. There are, of course, bad solid state amps, just like there are bad tube amps, but overall, solid state amps tend to sound much more alike as a group, if one leaves out the bad ones. SET's however, have a bigger variation in sound. Push-pull tube amps can sound very alike, but of course, they are much more expensive than SS, for the same power output.

 

[Frank_S]

Arnel said;Quote "I don't even remember hearing any tube amp that rocks."
I guess you have never heard what a Marshall amp can do. That's what most rockers use to make music,IE Hendrix. I also prefered tube amps when I played in bands in the eighties. Tubes give you a unique sound/tone that SS just can't offer. I don't have a tube amp in my 2 channel system as of yet but I do use a tube preamp with tube phono stage.
I will definitely be looking at putting a tube amp in my system shortly. I feel tubes get more of the music than SS, eventhough tube gear does'nt measure up on the test bench.

 

[Saurav]

Tubes give you a unique sound/tone that SS just can't offer.

Tube guitar amps are a great example of their ability to rock, but don't confuse instrument amps and home audio when it comes to 'tone'. That tone is a result of distortion, and in a guitar amp, the goal is to produce a controlled but relatively high amount of distortion in order to get that tone. In a home stereo amp, the goal is to minimize distortion, so that the music on the recording gets through. Any guitar tone is already on the recording, and you don't want the amps to be adding anything.

Chung is right, of course, SET amps have pretty high distortion figures. Based on my memories of playing in a band and listening to live music, I find the sound of SETs to be more true, closer to what the real thing sounds like. SS amps that I can afford sound a little lifeless and sterile in comparision. Of course, this is a matter of taste. There are many theories which try to explain in scientific terms why SETs sound better to some people, some of these theories are more believable than others. While there is certainly value to trying to find objective measurable results that correlate with subjective opinions, I'm not convinced that that exercise needs to be taken to the extreme. In other words, I usually go by what I like, and don't spend too much time trying to prove why I like it.

Chung brings up one very good point - a high quality low power class A SS amp will indeed sound very good when it is used to drive appropriate speakers. However, how many such amps do you see available to the general public? For instance, I can think of a handful of tube amps/kits that are under $1K that fit these criteria, but I don't know of any corresponding SS amps. So, while in theory the tubes vs. SS comparision is independent of the high-eff/low-power vs. low-eff/high-power comparision, for all practical purposes they become the same argument. Most available SS amps are high power, and they will not sound as good when driving speakers that only need a watt or two.

 

[Arnel Enero]

Interesting - what speakers were these tube amps driving? The system I mentioned before was incredibly dynamic. I think my current 8W tube amps are more dynamic than the 50W SS amp I had before. Of course, I have relstively tube-friendly speakers, and I think that is critical to getting the optimal performance out of tubes.

I agree. Problem is, my preference in speakers lean toward the likes of B&W Nautilus, Dynaudio, Wilson... you know, those speakers that demand watts AND current to deliver their goods. Too bad I never came to terms with high-efficiency speakers, horns or not... nor the relatively easy to drive standmount designs. I have the impression that most designers that pay attention to bass extension (while maintaining tautness) always come up with a below-95 dB efficiency design. And matching my preferred speakers with tube gear always failed to impress during my past visits to showrooms.
This is why I NEED solid-state.

 

[John Sully]

What Chung said.

 

[Saurav]

Problem is, my preference in speakers lean toward the likes of B&W Nautilus, Dynaudio, Wilson... you know, those speakers that demand watts AND current to deliver their goods.

That makes sense. I auditioned the Audience 52, and it was stunning. I was advised to stay away from the Contour 1.3 in the interests of marital harmony
I'm currently running 88dB monitors with 8W amps in a 15x20 room - fairly borderline, but it plays loud enough for me. Of course, there's a subwoofer in there being driven by SS watts. I intend to explore the land of high-eff/low-power a little... my current living room will not handle large floorstanders anyway, so I'm restricted to monitors (even though my bass tastes would probably be better met with floorstanders). That system I mentioned earlier had huge Oris horns being driven by a 0.5W DIY amp, and 10" woofers under the horns being driven by SS. My ears couldn't detect any discontinuities in the integration.
I'm no expert at this by any stretch of the imagination, but low power/high efficiency systems just seem more nimble to me, they seem to convey the rhythym and flow of music better. And I'm much more interested in that, than say tonal accuracy or sheer power.
Anyway... enough rambling

 

[Duke H]

Hey! I wear Bellbottoms...and spikey bracelets...and strange colored hair...and Converse All-Stars...I must be pushing some crappy 18"ers through a Technics receiver! No, just kidding. Interesting debate-very philisophical. Would one be better of reproducing musical tones as accurately as possible, or as pleasingly (ok, I know I'm being subjective) as possible? Frank, right on! Marshalls, Fenders, Matchless, VHT, Pignose, Ampeg, bring 'em on! Saurav's right though...not just a different ball park, but a whole nother sport!

The real reason I'm posting, though, is to ask a question: We're all familiar with the hybrid theory...tube preamp/SS power amp-What about doing it the other way around? I know that that may seem like a pretty stupid (dare I amend to "stupid and/or radical") question, but here's why I'm asking:

My Dad has an ancient tube amp just sitting around, and I'm thinking about bumming it from him. It needs a bit of work, but I've tinkered with/modified my tube guitar amps enough that I think I could get it up and running, provided I get a service/tech manual. I have a Yammie Htr-5560, and I was thinking about adding a set of high-efficiency speakers to my set up, and running them off of the tube amp (the 5560 has pre outs). That way, I'd be able to use speaker "B" for 6.1 surround (DVDs, CBL, DVD-A, etc) and use the tube amp (speaker "A") for listening to vinyl/CDs in stereo, a la tubes. Here's my train of logic (it's probably more like a herd of stampeding cattle, but I don't quite know how to best word that): Technics Turn Table to 10-band EQ ("smiley face"/"scooped mids" to compensate for vinyl's inherent Mid range boost ("frowny face"), to receiver Aux in (EQ doubles as direct box). Receiver (in 2-chan. stereo mode) feeding tube amp (main speakers, "A"), feeding a nice set of H.E. speakers (perhaps some studio monitors?). Is it worth the hassle (IYO)?

 

[Saurav]

to compensate for vinyl's inherent Mid range boost

First time I'm hearing about it. You do have a phono stage, right? If not, I wouldn't use an EQ to compensate for the RIAA curve, and that curve isn't a mid range boost, AFAIK. Go to the Radio Shack website and get their $25 battery powered phono preamp. It's excellent, and amazing for the price. Plonk down another $25 on 2 NiMH batteries and a charger (Home Depot, Target, anywhere), and see how much better your records sound.

I've read some opinions where the SS pre/tube power combination has been described as working very well, perhaps even better than the other way round. The reason given is that the 'tube sound' comes mostly from the way a tube amp interacts with the speakers. This school of thought seems to be in the minority, and I have no first hand experience with such a combination.

 

[chung]

Saurav:

Most available SS amps are high power, and they will not sound as good when driving speakers that only need a watt or two.

That's not necessarily true. Good SS power amps do not have crossover distortion. Most good SS power amps these days operate in Class A at low power outputs. I think as long as you don't overdrive your high-efficiency speakers to the point of gross distortion or damage, you should be fine with a high-power SS amp.
Nowadays most competent power amps are fairly high power: 100W or more. But if you look at power amps from 10 years ago, you will find the 50W Class A ones (e.g. Krell). I don't know why you would want lower power, though. You have more flexibility in speakers when your power amp delivers high power.
My point earlier was that it is much easier designing low power amps than high power ones, for a given level of accuracy. But even high power amps really are not a difficult thing to design anymore. There has not really been any advance in audio power amp technology in the last 10 years. The SET trend is a step backwards, IMO.
One thing worth noting is that a very clean (low distortion) amp does not sound as "loud" as one that distorts, even though SPL's measured may be higher with the clean amp. I remember reading a post by an AT&T engineer (JJ) saying that he replaced the PA system in a school from fairly bad amps to clean ones, and people were complaining that the new system was not loud enough. Measurements with a SPL meter showed that the new amp actually delivered higher SPL's. He finally placed a soft clipping circuit in front of the power amp to generate distortion, and everyone was happy after that
If you are used to the tube sound, a clean SS amp can conceivably sound "sterile" or "lifeless" at first because of the lack of coloration. But I believe that after a while, you will like the wider dynamic range, and the power and control of the SS amp more. I owned a couple of tube amps, and I found the "warm" and "sweet" sound tiring after a while. The solid state amps are much more transparent and clean to me. YMMV

 

[Saurav]

I owned a couple of tube amps, and I found the "warm" and "sweet" sound tiring after a while. The solid state amps are much more transparent and clean to me. YMMV

YMMV being the operative term here System synergy is a big part of the whole picture too - I have an opamp-based phono stage, and my speakers are pretty revealing, so tubes balance that out nicely, perhaps even leaving me with an overall more neutral system. The SS amps I have owned (that I can afford) just did not have as smooth a treble.
Speaking of opamps... next up on my fiddle/tweak list is using a FET and a resistor between the opamp output and the V- supply, to act as a constant current source and bias that opamp into class A with about 2-3mA . If I can hear any difference and I like it, I'll probably try that in the analog stage of my CD player next. Your inputs have been very educational for me so far, so do you have any comments on that?

 

[Duke H]

Saurav-My receiver doesn't have a phono stage, if you are asking about that. The Eq I'm using has a sensitivity regulator (correct term? It's called a direct box in the studio). I read somewhere that vinyl has a natural mid boost (low and high dampening/run off, I believe). If not, how should the EQ be set? Not trying to get off the subject, by the way. What does RIAA stand for?

Another point...what gave me the idea of using a tube power amp was the natural compression created by power tubes. I like the dynamics of it...even if I am (tecnically) generating more imperfections that if I were to go the SS power amp route. I guess the key would be finding the sweet spot...the point where you get compression, without destroying the tone. Again, this is coming from a guitarist's POV...not HT. What do you all think? Are my assumptions correct, or am I off base?