[RussKon]

I work at an electronics distributor for pro/commercial audio.... one of the few perks is the ability to take equipment home and "field test" it overnight or for the weekend.....

tonight it is a Goldline Real Time Analyzer - Model DSP30 - over $2000 retail.... it really has too many features to list here but the most important is the 30 band analyzer of sound... it includes a calibrated mic and resolution down to .25db....(1/4 of a decibel)
you can check it out at www.gold-line.com

really pretty amazing...(it better be for $2000)....

now to the point.... i recently aquired a dynaco sca-35 tube amp from ebay to replace a carver tfm-25 in my main system.... sharing this info at work...i got the responses...."tubes color the sound"... "tubes are o.k, but not accurate".... and so on....

o.k...let science help us..... on a test cd of pink noise for each channel and both channels combined.... the dynaco tube amp was down 4db at 16 khz and about 6db at 20 khz.... (now the best part) ... the carver results were almost identical.... the rest of the spectrum was almost flat....

(for the record... the dynaco is 17.5 watts per channel and the carver is 225 watts per channel)

the speakers are Klipsch KLF-30's mated with a Velodyne CT-150 sub set at 40 hz and about half volume....

RESULTS:

both amps produced almost the same result on a piece of expensive test equipment yet they SOUND RADICALLY DIFFERENT!!!!! ... my 5 year old daughter can hear a difference in the sound between the two amplifiers.....

frequency response measures pitch.... but I am not aware of any device available that can measure TONE..... yet we can all hear differences in tone.....

TONE is why we hear differences in most amps and speakers....yet no one talks about it.... as a musician, tone is a top priority...yet it is not discussed when talking about audio components.......???????

i'm probably preaching to the choir here...but i wanted to share my "scientific experiment" with this forum....

[Rob Babcock]

I hate to open a can of worms, but in a very recent interview, Bob Carver stated flat out that the main reason tube amps sound the way they do is output impedance.  He claims to have measured most of the decent amps out there, tube and solid state, and found that most of the tube ones measure 1 ohm.  So that's what one tap is set up as on his Sig amps.  

Now Bob has made a career out of "tricking" people into thinking his amps are tubed (not all of them, mind you); I recall his infamous challenge of years ago where he claimed to be able to mimic the "transfer function" of a magnetic field power amp to sound just like any amp you wanted.  For the most part he pulled this off.

I surely can't confirm nor deny the veracity of his statements, just thought of it since you specifically mentioned a Carver amp.

I have known people who've eq'd colorations into the input to their SS amps that have fooled people into "hearing" tubes, too.

Guess I have more questions that answers!

[john curl]

Sorry for responding so late, but I just got on this board.  There is a REAL difference between tubes and solid state.  It can be measured.  Unfortunately, an RTA is not the best way to do so.

[Curt]

You most likely measured your speakers frequency response in your listening room  That's why the curves are the same.

We use a lot of terms to describe the sound of a system. Check out "Sounds Like? An Audio Glossary" by J. Gordon Holt, July 1993 which is available in book form or as a printable download from the Stereophile website.

Tech toys are pretty fun, be careful you may get hooked  

[audiojerry]

Sorry for responding so late, but I just got on this board.  There is a REAL difference between tubes and solid state.  It can be measured.  Unfortunately, an RTA is not the best way to do so.

Assuming you have the proper test equipment, I would assume that the outcome will almost always bear out the SS as the winner in the measurement war?

Is there any one set  or group of measurements where the tube amp would exceed those of the SS?

Why do so many music lovers have so much affection for tube amps and reject anything that is SS, even when they know that SS has superior measured performance? Is it because tube fans just have poor listening skills?

Regarding tone, I believe timbre is a better word for tone. Timbre is the complex set of individual tones produced by an instrument or voice, vs. pure tones produced by an electronic device often used in test gear. I believe that the reproduction of timbre (capturing and keeping separate a larger part of the complex tones) is where tube amps surpass solid state amps, and that this is the difference that most people can hear.

I also believe that lp as a medium better captures timbre more accurately than redbook cd, and this is why many folks prefer lp's despite all of the "measurable" advantages inherent in the redbook medium.

[RussKon]

Assuming you have the proper test equipment, I would assume that the outcome will almost always bear out the SS as the winner in the measurement war?

Is there any one set  or group of measurements where the tube amp would exceed those of the SS?

Why do so many music lovers have so much affection for tube amps and reject anything that is SS, even when they know that SS has superior measured performance? Is it because tube fans just have poor listening skills?

Regarding tone, I believe timbre is a ...

poor listening skills???... well let's see... over 16 years as a music educator... over 20 years as a part-time professional musician... i feel that my listening skills are very good....

 i believe the opposite - tube fans have superior listening skills.... i am more concerned about the sound than the specs...... maybe you should stop reading specs about your amp and start listening to some music...

[Dan Banquer]

Distortion, Distortion, Distortion. Tube gear into a reactive speaker load typically brings out higher even order distortion and IM. If the tube gear is powering the subwoofer I think we can add a fair amount of clipping too.

[Psychicanimal]

poor listening skills???... well let's see... over 16 years as a music educator... over 20 years as a part-time professional musician... i feel that my listening skills are very good....

Here we go again...

[RussKon]

Distortion, Distortion, Distortion. Tube gear into a reactive speaker load typically brings out higher even order distortion and IM. If the tube gear is powering the subwoofer I think we can add a fair amount of clipping too.

you are correct about the "even order distortion" with tube amps....

also, you fail to mention that SS amps tend to emphasize "odd order distortion" which is very non-musical....

even order harmonics are very natural in the music making process....

2nd, 4th, and 6th harmonics are created by musicians when they play their instruments.... one reason suggested why tubes sound good even though distortion shows up on test instruments is that the ear and brain does not interpret the "even order distortion" as wrong or bad sounding.....

odd order distortion.... on the other hand is very noticible and emphasizes harmonics which are not produced in any quantity by a musician.....

[Dan Banquer]

That's not entirely true. Human hearing tests have shown a remarkable insensitivity to 2nd order distortion but as the distortion gets to higher and higher orders than human hearing gets extremely sensitive. This is probably due to the the way instruments are tuned: the scales are "bent a little" towards the top end. Ask a piano tuner.
Solid State can be made not produce odd order distortion. I should know; I make gear that does exactly that.

[RussKon]

That's not entirely true. Human hearing tests have shown a remarkable insensitivity to 2nd order distortion but as the distortion gets to higher and higher orders than human hearing gets extremely sensitive. This is probably due to the the way instruments are tuned: the scales are "bent a little" towards the top end. Ask a piano tuner.
Solid State can be made not produce odd order distortion. I should know; I make gear that does exactly that.

then please explain why many people including myself prefer the sound of a tube amp over solid state amplifiers.... or is it just that i have not heard your SS amp??

additionally...if it is possible to make a SS amp with no odd order distortion, then why is that distortion so prevalent in SS amps?

[Marbles]

poor listening skills???... well let's see... over 16 years as a music educator... over 20 years as a part-time professional musician... i feel that my listening skills are very good....

 i believe the opposite - tube fans have superior listening skills.... i am more concerned about the sound than the specs...... maybe you should stop reading specs about your amp and start listening to some music...

You should be aware that Audiojerry has tube amps and wasn't trying to run you down but ask a legitimate question regarding (maybe) himself.

[RussKon]

poor listening skills???... well let's see... over 16 years as a music educator... over 20 years as a part-time professional musician... i feel that my listening skills are very good....

 i believe the opposite - tube fans have superior listening skills.... i am more concerned about the sound than the specs...... maybe you should stop reading specs about your amp and start listening to some music...

You should be aware that Audiojerry has tube amps and wasn't trying to run you down but ask a legitimate question regarding (maybe) himself.

no offense intended.... but i get the same comments from co-workers with their SS amps and receivers when discussing audio.... lots of talk about specs but not a whole lot of talk about music....

[Dan Banquer]

I don't know exactly why it's so prevalent. I will take a guess here. Most designers will go for a low THD spec. THD; meaning Total Harmonic Distortion, does not tell where the distortion components are, whether they are 2nd order or 9th order. As you have noticed a low THD spec does not mean that there is no audible distortion, especially when the load becomes reactive as a loudspeaker load can.  Hope this helps. I talk more about this on web site in the FAQ's section.

http://www.redesignsaudio.com/faqs.html

[RussKon]

dan,

thanks for the link!!!

lots of interesting reading....

[audiojerry]

Assuming you have the proper test equipment, I would assume that the outcome will almost always bear out the SS as the winner in the measurement war?

Is there any one set or group of measurements where the tube amp would exceed those of the SS?

Easy there RussKon, I was on your side - the above comments were directed at John Curl.
I've gotta look out for friendly fire    

I'm going to start a thread that takes a shot at solid-state owners. Things have been too quiet around here...