Axiom Home Page Forums General Discussion Home Theater Tubes?

Fordprefect ... Not trying to pick on you here, but Sound and Vision remarking on high end audio is about the same as McDonald's commenting on fine dining...

Ouch! I dont recall Sound & Vision doing reviews of gawdy shelf systems, which would put them more in line with your analogy. Surely you're exaggerating just a smidge.

If not, are you suggesting that people defenestrate their entire collection of S&V mags?

Hi FordPrefect, the kid, and all,

If we are speaking in a technical sense, tube amplifiers tend not to be "linear" as solid-state designs; that is, the frequency response isn't as smooth, so certain octaves in the musical spectrum may get slightly emphasized or (more commonly) slightly depressed, especially in the midrange. Virtually every solid-state amplifier these days delivers ruler-flat frequency response, especially if you switch out the tone control circuits which may introduce audible blips.

It is partly these non-smooth variations over the musical spectrum found in many tube amplifiers that account for the differences in sound quality heard in comparison tests. However, if a tube amplifier is properly engineered to yield linear response, these differences evaporate. I speak with some authority here, having done A/B double-blind tests using Macintosh amplifers along with solid-state amps. One of the other panel members was Ian G. Masters, whose quote from a current issue of Sound&Vision is cited by FordPrefect.

One enlightening demo illustrating the above was done by Bob Carver, who claimed he could make a solid-state amplifier that sounded exactly like tube amps. He did that, and to achieve it he altered the frequency response of the solid-state amplifier, adding a midrange slump in response (that adds a subjective sense of "depth" to recordings) followed by a lift in the upper octaves, to add a sense of "air" and "bloom" to the instruments, the latter both qualities adored by anti-science types like Harry Pearson, founder of The Absolute Sound.

There are also interactions of tube amplifier output stages with a speaker's impedance curve that may introduce quite audible errors in frequency response, and those will be peculiar to a given set of speakers, and will be different with another pair of speakers. Solid-state amplifiers have essentially 0 ohms output impedance, so these variations away from accurate response do not occur.

In short, tube amplifiers are inaccurate, non-linear devices for the most part. It may be fun for hobbyists, and those glowing orange filaments sure are purty, but accurate sound is not a virtue of tube technology.

Regards,

Hmmmmmmm... well... when I logged onto their site, the Bose Wave Radio was archived in a review... but... how about we give them Wendy's Status...

Oh, gee, I didn't know the scientists have reached a consensus that tube amps were [censored]. Not to put too fine a point on it, but the arrogance of it! Personally, I follow the reviews of Steve Rochlin at Enjoy the Music, and Pearson at TAS, and find that my experiences match theirs in many ways, including their appreciation of both some tube amps and Axiom speakers. But hey, what do they know!

2x6, well of course you follow the reviews of Rochlin and Pearson. Their opinions are more in line with your current views.

Please don't take every criticism of tubes as a personal attack. Why should the opinions and experience of others detract from your enjoyment of tubes? Nobody here has said tubes are [censored].

i will say it.. tubes are [censored]

but what do i know?? not much..

i agree with peter on this 2x6.. everytime this tube issue comes up, you get your panties all bunched up in a wad.. good lord man, its just a box with some pretty glowing tubes.. you dont need to get bent all outta shape.. PLUS, the bottom line is.. you dig what you got, and you love the way it sounds.. so there, you da man, and those that have the same enlightenment as you, are also blessed.

to be honest, i would LOVE to hear a good tube amp, just so i can make my own decision. i respect your knowledge on the subject, and i know you wouldnt be defending your stance so strongly if it didnt sound very good.. but, i am at a loss. i dont know anyone with a tube, nor do i know where to search.. but my curiosity grows with every one of these tube threads!!

bigjohn

Thanks Allan, thats the kind of comments I was looking for, I was sure there had to be some science behind all that emotion.

Not that there's anything wrong with emotion, I can understand the feelings that some of you have towards tubes. They look incredible and I hope that sometime I can hear one.

As for Sound and Vision, well I like it. I like the equipment they cover and I like the layout of the magazine. Feelings shouldn't enter into this at all, we all enjoy audio and it would be a very boring world if we all marched to the same drumbeat.

FordPrefect, I really was just teasing... S&V DOES do great measurements, and their amp tests are great... I do wish their speakers tests were more thorough...

Kid, a correctly-designed tube amp can be just as transparent(flat frequency response, inaudibly low noise and distortion)as a well-engineered solid state design and neither will audibly affect the sound, except to amplify it of course. One of the illustrations of this was the blind tests years ago by Stereo Review, one result of which was that a $6,000 pair of tube amps was able to match the performance of a $200 solid-state stereo receiver and couldn't be distinguished from it. However as Alan has pointed out, some tube designs have problems with uneven frequency response due to their high output impedance following the swings in speaker impedance. Another problem that can arise in the low power tube SET amps(e.g.5-10 watts)which can sound clean at moderate levels is the second harmonic distortion which they can exhibit when forced to high output levels. Sometimes tube enthusiasts attempt to use attractive terms such as "warm" or even "musical" if these problems arise, but an amp isn't supposed to be a musical instrument.