I have often heard people say how tube amplifiers sound warm, whilst other amps sound neutral and flat....

And heard people say they prefer the tube sound for it's warmth, even if it's less accurate.

So my question is, harmonically, what is "warmth", or lack of it? What frequencies are boosted or supressed?

I've tried searching (here and on google) with no luck....

ROFL, this should be interesting <waits for the comedy to roll>

Technically, tube amps create a 'warm' sound by creating even order harmonics when they are distorting (which the ear finds pleasant) and not many odd order harmonics (which the ear finds unpleasant), so when distorting slightly they have a distinct sound that solid state amps dont have. Solid state amps generate odd and even order harmonics in roughly equal amounts 'Better' or not is subjective, but tubes are certainly different

As for solid state amps... i'm looking forward to the explanations of how a solid state amp with less than 1% THD and a frequency response flatter than Bobby Digitals sister can sound 'warm'

Tube amps heat up the sound as the sound passes thru the valve, and then by the time it reaches output it cools slightly therefore giving your speakers a WARM sound .

ROFL

It has been my personal experience that sounds associated with the term "warm" tend to reside in bass frequencies, particularly around 100-315 Hz and centered around 250 Hz.

Its all a crock of .... Tom, your brain tricks you into thinking your hearing a better sound from those amps..when the difference is not audible really.. Even though i'd take a pair of Milberts anyday!

Your wrong buddy.

Why dont you put an RTA onto a class AB amp and a Tube driver.

Generally the difference is in the upper range not the lower range. It actually makes the higher frequencies a little bit more detailed so you hear things that there normally arent there with solid state amps.

Yup, they're called 'secondary harmonics', or more commonly, 'pleasant distortion'

Its not extra 'detail', just extra audio information that isnt recorded there in the first place

Yeah warmth doesnt really relate to detailed or natural. Or even neutral.

You feel warmth from wood instruments imo. Around the 300-800hz region. Where this is boosted slightly. It is the full sound that kind of hugs you.

In terms of soundwaves - waves that are square or clipped are the opposite of warm. (= harsh.) Warm waves from analogue equipment (usually) dont have this harsh effect, but generallly trim the sine wave at its peaks creating what sounds nice to our ears. Although not necessarily accurate.

Well they're my thoughts anyway

The distortion differences are pretty major in effect. With solid state it seems we have to chase the barest minimum THD figures to get a clean sound, whereas its not super critical in a tube amp. Therefore they can concentrate on other aspects of the sound when designing a tube amp.

I run a tube preamp and amp for my home rig, and while not having the same punch, it leaves the solid state amps for dead. Particularly in music such as Tool when it sounds like heaps of treble crashes in all of a sudden, most amps struggle to keep the treble from becoming almost a "treble mash" but the tube amp handles it perfectly, and every instrument clear, smooth and distinct. Vocals as well have an eery reality to them. I don't think I'd go back unless I heard a bloody good solid state amp that could compete.

Solution to 'treble mash' from solid state amps : dont by ones with sh!tty power ratings, if you want top knotch solid state performance you want to have more power than God Not because you will actually use the power, but because lots of power + medium volume listening = lots of headroom, = little clipping distortion, = not much odd OR even order harmonics, = sounds clean as a virgins tits.

Low power tube amps = fine... but low power solid state amps = planning to fail.

Oh, and BTW, THD ratings on amps are meaningless beyond a certain point. Sound does not exist at one power output level, it fluxes all over the place... your musc will have lulls and crescendos where there may be a factor of 1000 times more/less power than the opposite end, all at a certain 'average' volume level you've set. And the THD is not linear, its all over the place, especially as output wattage rises.

So to put it simply, having an amp thats rated at 100w @ 0.0001%THD makes not two tits of difference if your music and volume combine to swing your output power between 0.1w and 300w during playback, and the amp is driving 5% THD @ 300w

this is going to be a damn good read by the end...

now i haven't heard tube amps in car stereo but in guitars i can tell you all about it. since when playing guitar distortion is often your friend tubes are the shiznak!

when using tubes on a clean guitar amp they are much more enjoyable to listen to as they sound not electronic but more like a guitar makes without electronic amplification. i tgives it a sort of strength to it...that's the best way i can explain it sorry. i am bout 99% sure it does this by distorting the cleans a little but so little it isn't hearable to the human ear (or at least mine) or some distort it more so that when you play softly it sounds "clean and strong" but when you really give the strings a bit of abuse the notes distort.

Rhyso

Tubes in guitar amps work the same way tubes in home audio amps do ; they amplify while filtering out the 'bad' distortions and deliberately creating 'good' distortions (if there is such a thing)... but since distortion isnt something to avoid but is actually something you WANT with guitars, the difference between tube and solid state is more striking that in home/car audio

Tube amps dont deliberately create good distorations (the guy who invented tube amps didnt make them thinking this will create distoration that sounds good)

Its just in the nature of the way the tube amps work that the distortation created by them sound good to a degree. Pushin them past their limits will obviously still sound bad.

Tube amps were originally invented because thats all they had to use, not because they were some mysterious feelgood factor

And yes, tube amps 'deliberately' create 'good distortions', as thats the only reason you buy a tube amp If a tube amp DIDNT distort, to any audible degree, it would sound EXACTLY the same as a solid state amp. Its the even order harmonic distortion that creates the 'tube sound'

Dude you just have way to much knowledge how the hell can you sell anything to a customer .

You'd be surprised what people will buy when you dont patronise them (not suggesting any dealers on here do)...

Besides, you dont drop the book on every person who walks through the door, its easy to keep it simple but still accurate... its only when people want specifics that you really get nitty gritty

I suppose its just a matter of personal pride, i dont like feeding people misinformation even if its not deliberate... i never want to be one of these retailers you hear people talking about when they say "I went to such-and-such and they told me <insert incorrect statement>, what a crock of ****" Plus i'm just extra inquisitive by nature : its not enough to know it works, i need to know how, and why

Anyway, getting off topic here Heres something to get things going : howcome if warmth is frequency based, you often hear amps described of as 'warm' and yet speakers, which have MUCH greater variation in frequency reponse, almost never are described that way? Afterall, +1db at a particular frequency is the same +1dB whether the cause is the amp or the speaker, right?

What about those valve amps that sound hard and brittle?
Not all tube amps sound warm and sweet.

The execution perhaps?

Not sure about the ones you're referring to Steve, but oftentimes the ones that sound like that only use tubes on the input stage or (rather sadly) cosmetically only... the majority of tube amps, even, would be like that

The majority of proper full tube amps (i.e tube output stage) should have a warm sound to them... i've certainly never come across any that havent, but you've been around longer than i have Any models/brands you've found that with?

I've played thru' "all Tube" amplifiers that I had to fight for tone, totally flat response like Solid state.(that gig was a struggle ). Distortion in tube guitar amps comes from 2 sources. Power tube Distortion (EL34 tubes) & Pre-amp Distortion (12AX7 tubes). Power tube distortion is the cleanest and hardest to achieve as it means driving the amp from the master gain and is limited by the pain in your ears (God bless power soaks) I have a 200w Marshall which can really hurt. The easiest, dirtiest and low volume method is driving the pre-amp tubes & from memory I think it does this by changing the bias between a matched pair of tubes, the further out of bias the more distortion. So................
Comparing instrument amplifiers to HiFi components to me seems moot. Everything from your technique to your Guitar to the speakers including all in between creates your "sound" and colours it too.
Now (correct me if im wrong here) with HiFi it is generally prefered to recreate the original signal as it was recorded without influence or coloration from the components re-creating it. i.e. speakers/ deck /amp etc. After all the "warmth" is supposedly in the recording already is it not. I'm sure tube CA amps use one 12AX7 pre-amp tube (no bias = no distortion)

Coming from a Pro Music background I'm not sure I can appreciate Valves in a "Car" Audio System. There just aint enough smoooooooth aussie roads around.

Valve amps create a "warm" sound by using second order sub harmonics. A valve amp can reproduce more than one frequency at a time most solid state amplifiers do this but at a suppressed level because of the lack of power supply Valve amps genereally are fairly high current draw. the warmth is created by the fact that even when over driven into clipping the signal cannot square wave (ok in certain instances i belive it is possible but im yet to have someone show it to me). I dont know the technical data for how valve amps do what they do i just know what they do and i can only explain it the way i understand it - which may or may not be correct!

The "warmth" is not generated by the signal warming up then cooling down and im guessing that that was a sarcastic comment if not it was wrong cause why dont solid state class A amps sound f***ing hot!

Unfortunately Blackrazor is right about the fact that now days its not uncommon for a "valve" amp to be a solid state amplifier with a valve (quite often with an on off switch) purely for asthetics.

Winno are you talking when Valves have just been replaced? because i have heard a similar sensation (i dont know that i would have described it quite like that but any how) when valves have just been replaced. I put this down to the fillament not quite at its optimal malleability do to the fact that the tensile strength in the wire hasnt bean achived by the heating and cooling process (also why Valves sound flat when they are on their way out)

Sub harmonic distortion (or sub harmonics in general) are something that valves reproduce better than solid state - i dont belive solid state amplifiers dont generate them at all. And I also belive that this "sound" or electronic pulse/signal what ever will change depending on the speakers it is attached to because the fluctuating impeadance of the moving speaker has an effect on the draw of the valve stage. You can affect the sound and life span of the valves by appling different voltages to the valves.

as for THD - I think THD is wank absolute wank at that. at normal listening levels tell me who can hear one millipooftenth of a percentage of THD and THD doesnt refer to the entire spectrum. I think what people are hearing when they talk about harmonic distortion in that sence is actually more down to amplifier architecture more than electronic distortion.

I think that Valve preamps are a nice thing to have because they give the best of both worlds the allow an over driven signal to be compressed as such before being delivered to a solid state "sterile" power amplifier. I dont think that its good for solid state equiptment to be subject to such loads how ever as the end user has a tendency to turn up the volume more. I preffer a full valve stage integrated amplifer though because then the signal retains its full dynamics allthough with added distortion - or coloration as it may actually be.


DISCLAIMER: The above may be entirely a crock of crap. This is my understanding and experiance with Valve amplifiers. Fell free to roast me

It was a joke KOMODO .

But it makes sense doesnt it .

LOL yup

I didnt realise it was posted by you streetsoundz lol

I think tubes remind us that obtaining the absolute purest reproduction of a recording isn't truly the ultimate goal in hi-fi. This is flawed, and will only leave you disappointed in recordings, and too conscious of the sound you are hearing, when you should be conscious of the music you are hearing.

A wise man once told me about the "cycle" an audiophile goes through. First they have a love for music that inspires them to chase the ultimate in sound quality and reproduction. This leads to a fanatical chase that will always overtake that actual passion for the music that inspired it. They soon get lost in following every avenue, different amps, speakers, sources, and when the reach that pinacle of quality the realise they now choose their music based on what will actually sound OK on their uber special rig.

The cycle is complete when the fool realises they are out to listen to music, and how realistically the tiniest detail of that flawed recording plays and irritates you is purely a distraction from that musical goal. He then starts listening to music again and is inspired. =) (paraphrased from a guy in a kit speaker store, but he knew what he was talking about).

Meh I've had a long day and I'm dribbling, but all I know is that people with their super expensive solid state gear have had shivers up their spine listening to my home rig with tube amps, literally amazed to hear music again. They didn't complain for a second about distortion btw, they were too busy enjoying music.

I agree findog! I have a friend with an uber special system (home), who has spent craploads on it. When he plugs the solid stage in, it sounds 'colder'. With the tubes running, its a lot warmer. He loves the accuracy of his top of the line Solid state, but for LISTENING, and sounding the best, the tubes anihilate the solid state.

Relax chap it wasnt really a serious call.. Tubes sound more detailed, but i wouldnt get one in a car audio setup

After hearing what a difference an MTUBE-8 makes, i'll definitely consider one in my next install B)

Hahahahahahahah ok

LOL whats so funny?

Nothing im installing my MTUBE8 when my Sinfoni amps arrive soonish .

Nothing im installing my MTUBE8 when my Sinfoni amps arrive soonish .

alot of the "tube" sound also comes from the output transformer, which does have an impact on sound, as its impedance does vary with frequency as well as its internal capacitance etc. so it has a huge effect on the sound.

Very true. It seems that there comes a point where you think people are just chasing what is meant to be quality, sure say for example two sets of speakers, they will sound different but which one actually sounds better? How do you know what the most accurate recording sounds like? How far do you go? I havent actually listened to tube amps so I cant comment on them though. I do remember reading on some other forum though (home sound not car though) that had a detailed description of what "warm" "bright" "neutral" and all those terms and what they are considered to mean.

only problem with tube amps in your car that there is a chance they will get damaged since they are installed in a vehicle that is constantly moving. Im not changing my driving style in my work car to save a tube.. Anyone with issues in the car environment with their tube amps? feedback would be appreciated

Search I'm pretty sure it came down to some tubes are more resistant to the car enviroment than others.

Bump, I want feedback on this issue of tubes in a car environment. I'm considering a tube preamped amplifier for my vehicle, but the suspension is real stiff (7kg/mm and 6kg/mm spring rates).

why dont you make a suspension system for the amps?

Good call for using tube amps in your car.. because they will need it with a spring rate like yours

you can turn the heater up and get that "Warm" sound...

whats that ment to mean??


Marc made one for his carputer

i just love these analogies!!!!!

MUAHAHAHAHAHAAAAAAA!!!!

Im just agreeing with you blanky on that one

Hot
Dangerously high DC biasing ~400v
Short life span
Not much power output - completely unideal for tiny little inefficient small box speakers.
You see tubes being used by audiophiles with massive efficient horns for a reason.

It still is possible however.


He often is right The hybrids are the latest craze.


SUB harmonics never occur in amplifiers unless clipping is occuring. Then DC or AC coupled amplifiers clip in different ways,some go spaz outputting heaps of DC into your speaker.


People like to measure something,no matter how useless the information is.
Google GEDLEE METRIC or similar.


Valves will add the warm ness no doubt. But then the purists would argue that the sand amps would make it all harsh again.
Ive never heard a valve amp.

Lastly,valve amps distort much more slowly,the distortion products are lower order. It has to be true - you can see the distortion curves of valve amps/low NFB amplifiers being smooth and gradual, while transistor amps flat - then sudden. Perhaps peoples amps are clipping all the time causing 'harshness?'


I think the blame placed on sand amps sounding harsh is probably due to designers using nonlinear circuits -then forcing it linear with heaps negative feedback - but its well known that NFB doesnt reduce ALL distortion as magically as some claim.

Purist 'audiophiles' seem to like amps with no negative feedback at all,and valve amps tend to have little.MOSFETS can be used too.

http://milbert.com/tstxt.htm