Instructables

Are tube type amps really better than solid state type amps?

A question below reminded me of this. My friend and neighbor plays a guitar and has been going on about how great his new Fender tube amp is and how much better it sounds than the solid state amp he previously used.
Truthfully, I've listened to him play on both (he's no Chet Atkins for sure) and I can't discern much, if any difference. I've done a little research and heard words like, "warmer,"  "more vibrant" and "louder" used to describe the difference. With the exception of louder, most of these descriptions are not actually measurable. Is there a way to definitively say tubes are better, or is it just a subjective quality that depends upon the ear of the listener?

gmoon4 years ago
Objectively, there ARE measurable differences between tubes and SS amps.

-- Even-order harmonic distortion (second-order, mostly) is very easy to achieve with tubes. It's the type of distortion that makes music sound "full," while odd-order (3rd, 5th) distortion sounds harsh.

Traditional BJ transistors tend to clip rather abruptly, which leads to the harsher sound.

-- Tubes tend to clip in a more gradual fashion compared to solid state. Actual clipping leads to the odd-order distortion that spices up the sound--adds some bite.

The two types of distortion mix together easily in tube amps. Not quite so easy to achieve w/SS.

-- Tube amps distortion also tends to have different "flavors" in the preamp triodes vs. the power amp pentodes, which leads to a certain richness of tone.

It's arguable that the deficiencies of valve technology are what leads to the classic sound of tubes--soft clipping, output transformer saturation, etc. For instance, the old amps had poor power filtering and vacuum rectifiers, which would lead to "sag" (a natural form of compresson) --something actually desirable for guitar amps.

But there are certainly BAD sounding tube amps, and some SS amps sound great for some kinds of music--Dimebag swore by solid state amps, so metal is one of those genres that thrives on odd-order distortion. Modern transistor technology (JFET, etc.) can mimic tubes a bit better, too.

To top off all the arguments, good-sounding tube amps are much simpler than good solid-state amplifiers. A good solid-state amp requires much more electronic expertise to design...
rczili gmoon1 year ago
"Push-pull amplifiers use two nominally identical gain devices "back to back". One consequence of this is that all even-order harmonic products cancel, leaving odd order products to dominate. A push-pull amplifier is said to have a symmetric (odd symmetry) transfer characteristic, and accordingly produces only odd harmonics."

"A single-ended amplifier has an asymmetric transfer characteristic, and produces both even and odd harmonics. As tubes are often run single-ended, and semiconductor amplifiers are often push-pull, the types of distortion are incorrectly attributed to the devices (or even the amplifier class) instead of the topology. Push-pull tube amplifiers can be run in class A, AB, or B. Also, a class B amplifier may have crossover distortion that will be typically high order and thus sonically very undesirable indeed."

Source: http://en.wikipedia.org/wiki/Tube_sound#Harmonic_content_and_distortion

gmoon rczili1 year ago
Right--you quote some characteristics of different output stage topologies.

But it's accepted that the 2nd order (even) distortion of PP tube amps comes from the triodes in the preamp stage--a push-pull output stage only cancels the even-order distortion it creates itself. Any even-order distortion produced in the preamp is amplified, not cancelled.

You can verify this yourself--download the "Common Gain Stage" PDF at Merlin Blencows website: The Valve Wizard. With the info in the document, you can design your own triode gain stage, draw the load line and even figure the amount of 2nd order distortion the stage will produce...

Hint: triode tubes produce even order distortion due to the asymmetrical nature of certain crucial characteristics, which are mirrored by the transfer charts of the tubes. It's pretty easy to draw the load line, and see that the the gain characteristics on each side are not equal.

And of course, single-ended output stages can produce even-order distortion on their own, of course.

If you ask me, the much vaunted 2nd order distortion of tube amps would be pretty boring without some of the "bite" that 3rd and 5th order bring to the table.
Burf (author)  gmoon4 years ago
Very informative, thank you. Another new thing I have learned even though I still can't say I can tell any difference in the sound of the two.
by the way, I love the job you did on the green and black finished guitar.
orksecurity4 years ago
This is a religious argument. There is no reason they *should* sound different in normal operation. They often have somewhat different distortion modes when you push them past their design limitations, but that isn't inherently better or worse, and exactly what the differences are depends on exactly which circuits you're comparing.

In general, when people have done double-blind tests, the audiophiles who claim to hear a difference have not been able to pick out the tube amp.

So I think it's mostly placebo effect -- people expect to hear a difference, so they convince themselves they hear a difference. On the other hand, if it makes the performer feel more comfortable, that illusion may be worth the cost..

Basically, it really isn't worth arguing about. My take is that tubes are more trouble than they're worth unless there is something VERY specific that you're trying to do -- in which case you know enough to not need advice. But this is an area where rationality doesn't have a lot to do with the opinions.
The argument is not really of the religious variety. Experienced guitar players are usually looking for sustain and not so much distortion. For those not familiar with sustain, it is when the note played continues to "ring". In a tube amp the sustain is very controllable. Sustain can easily become feedback. Some players like feedback, this is especially true with metal players. Solid State amps create sustain through odd order clipping and instead of the note continuing to ring there is a squeal added to the sound. Lots of Jazz players prefer solid state as they are looking for a clean, multi-note sound. Not much string bending and an openness where dissonant chords and notes stand out. A solid state amp is great in these applications.
Tube amp players are usually wanting even order sustain whereas the note continues to ring without the added squeal such as a blues player who wants a single solo note to ring out a whole measure without distorting. It is certainly not a placebo effect and anyone, player of not can test for the difference. Set 2 smaller wattage amps side by side. Turn up the volume on both amps 3/4 of full volume. Place your fretting finger on the 3rd string at the 7th fret. Pluck the string and hold it and you will quickly see the tube amp is no sugar pill.
That doesn't mean you will like the tube amp better, but you will see it is not a minor difference, the difference is huge. The difference is so huge that even a drummer can tell the difference.
That goes back to the question of overdriving your amplifier.

If the amplifier is designed with sufficient headroom for the intended application. I admit that guitar feedback, and the controlled feedback used as sustain, is a special case which does tend to drive amplifiers hard -- but If your guitar amp is clipping, you really should get an amp which has sufficient headroom.

When overdriven, tube amps also clip. The difference is that they tend to clip more softly -- the waveform gets compressed at the extremes rather than than being cut off sharply, unless you REALLY overdo it -- and thus do not produce the characteristic harsh sound one associates with clipping.

In this special case, the tube amp may in fact be "more musical". But it _is_ a special case, and if you were using the right amplifier -- in either case! -- it would be back into the "no difference is no difference" range.

If you don't abuse it, tubes have no advantage. If you are going to abuse it -- well, it depends on what effect you're looking for. Clipping is sometimes deliberately used as a guitar effect, after all. And if it's complaining when you don't think it should be, you need a better quality amp, of either type.
I have been doing sound work for years as well and I do know the problem of the guitar player wanting a miked cabinet over line out. The problem arises when running a guitar into QSC RMX 5050 and expecting to get a sound like Billy Gibbons of ZZ Top. One of the most used recording amps are old fender champs. a 5 watter. The reason for this is the sound it makes when over-driven. At this point, I guess you could call it an effect, but it is not an improper uses of the amp. Adding additional headroom will distroy this "effect".
Surely before the invention of the push/pull circuit, amps were not designed to be over-driven. This would not make sense as an over-driven Oboe would not sound very good. The tube amp is part of the instrument where guitar is concerned. Is there a difference in sound between solid state and tube amps when neither is over-driven? Certainly there is, because no 2 amps sound the same due to resistor tolerance, grounding plans and the quality and age of components.
Abuse is very subjective. Is a NASCAR engine being abused when it is over-driven?
We agree that guitar amp is a special case; you're looking for a particular degradation mode. Entirely reasonable.

(See my own response to my post.)

On the question of "Is there a difference in sound between solid state and tube amps when neither is over-driven? Certainly there is, because no 2 amps sound the same" ... That may be true (though I think it's overstated), but if so it isn't primarily a tube versus transistor question. And it isn't clear which, if either, is inherently "better".

And double-blind tests consistently indicate that listeners can't tell the difference between tube and transistor when the amps are of the same architecture and equal standards. A difference which makes no difference really is no difference.
The initial question stated his friend got a new fender amp and how much better than it sounded than his previous amp. We are not talking about listeners to Macintosh vs Yamaha. In blind test, I can see where it would not be possible to tell the difference, but if you take my fender super reverb and remove the RCA 6L6GB's and replace them with Sovtek 5881 (6L6GB Russian), it will make a huge difference. Better? Not to me.
You can go further and state an MP3 is the same audio quality as a Reel to Reel. In blind test, the majority would select preference of the MP3, but scientifically we know the tape has more information and personally I can hear the difference. I can also hear the difference between a CD and Vinyl.
The question posed is Guitar tube amps better than solid state. If you are playing music that needs tube over-driven sound. Is a 1957 Hammond b-3 with a 147 Leslie better than a K-mart Casio keyboard?
I use and build tube guitar amps, but I would not use one in my sound system or for that matter for my surround home entertainment center.
For guitar, tube amps have advantages which solid state cannot provide, not yet anyway. It is very easy to make a guitar tube amp sound like a solid state by simply bypassing the tube preamp and use a digital processor, but currently it is not possible to get tube overdrive from a solid state amp. I have used some pedals which get close, but when the sustain begins to fade your left with the squeal. For electric guitar, my vote is for tube. I even like tube mic preamps. This debate has been going on for years, but during the 80's Solid State lost in the guitar market. You don't see many Boutique Solid State Guitar Amp Companies. Can all those people just be fooled by insidious marketing?
Having said that: For an electric guitarist, the amp is part of the instrument, and the warts in the amplifier's design are part of the instrument's sound. (Which is why electric guitarists annoy us sound techs by asking us to mike the amp's speaker rather than taking a DI feed... that makes managing the house sound MUCH more difficult for us, but it lets you get closer to the sound you hear when rehearsing.) A better amplifier is not always a better instrument, and you should buy the one which behaves the way you want it to, no matter what the theory says.

Or no matter what reality is, for that matter. If it makes you feel like a better performer, you're likely to be a better performer. This is a case where placebo effect can have legitimate application.

(And, yes, I have some experience as a sound tech. But I must admit that I'm biased since my experience is mostly folk and related styles, where the amp's job is to Get Out Of The Way and let the music come through rather than to add its own colors -- my training is to be part of the room rather than part of the band.)
+1. Don't overdrive it, and you shouldn't be able to tell the difference.
lemonie4 years ago

They sound different.

Whether they are better or not is a matter of opinion, and yours is just as good as anyone else's.

L
CrLz lemonie4 years ago
lemonie has it  exactly.

The sound differences become the most apparent//useful when you push the amps into distortion.  Tubes will distort one way, solid state circuits will distort another.

Really, what you'd want to choose is the particular distortion, not try to classify "best".  And different tubes will distort differently (just as different IC's will do).  So its not enough to say tube or solid-state.

Exploring all the possibilities is endless, but in the past (like the 70's...) there was much less options and development each year.  So musicians more thoroughly explored the distortions possible and developed some "classic" sounds. 

Seems like achieving/copying these classics is the main reason for tube-nostalgia.
lemonie CrLz4 years ago

Distortion is a wide area, you covered it well.

L
CrLz lemonie4 years ago
For real- gmoon's answer goes up to11.
NachoMahma4 years ago
.  Everything else being equal, a tube amp tends to have a "warmer" sound, but things are seldom equal. For most uses (within the amps "normal" range), the speakers used, room acoustics, speaker placement, &c will make more difference than the amp you are using.
.  As others have mentioned, tube amps overload/clip in a manner that a lot of ppl find more pleasing than solid state. Ain't nothing quite like a Marshall stack. ;)

Re-design4 years ago
Yes! No! Yes! No! Maybe! I don'know. I got both and like them all.

Ignore all the opinions and find an amp you like and go with that.  When you find one you like better trade up!
. +1