Ears vs. Measurements

[mep]

Mark, here is what you said in a recent thread with nearly the same title....

Let's turn this around to the real question: Do we know how to measure all of the parameters of sound that our ears hear? This is another one of those circular arguments that goes nowhere. If you take a look at the basic measurements that are used on the stereo gear that is actually measured, one could make a case that we can't hear better than the basic measurements. However, the real problem is that we haven't figured out how to measure everything we hear which explains why gear with similar specifications might not sound similar to our ears.

!!!!!

Not the same topic at all Tom. I'm not discussing how SS amps that measure somewhat close sound so different. This is more about a tube amp that is sold as a 75 watt amp at 0.6 THD and it doesn't come close to meeting those specifications and why in spite of that, it's still a damn good sounding tube amp.

 

[Robh3606]

Not the same topic at all Tom. I'm not discussing how SS amps that measure somewhat close sound so different. This is more about a tube amp that is sold as a 75 watt amp at 0.6 THD and it doesn't come close to meeting those specifications and why in spite of that, it's still a damn good sounding tube amp.

Becasue it's almost all 2nd and third harmonics and we all know THD in basically a meaniless measurement. Search for the Geedes Distortion Metric. Power on the other hand you most certainly will hear when you turn things up. On a pair of 101dB Horns not so important, on a pair of 84dB floorstanders much more important.

Rob

 

[KeithR]

maybe the speakers you heard were the more defining characteristic at shows, not the amp. NOLAs in particular have a really "unique" sound that i found good on cheap Primaluna monos (cost half as much as a Ref 75)

when I moved to high efficiency speakers, it was much easier to tell signficant differences on amplification..and that's because i'm hearing way more than before on 86db speakers

 

[Johnny Vinyl]

maybe the speakers you heard were the more defining characteristic at shows, not the amp. NOLAs in particular have a really "unique" sound that i found good on cheap Primaluna monos (cost half as much as a Ref 75)

when I moved to high efficiency speakers, it was much easier to tell signficant differences on amplification..and that's because i'm hearing way more than before on 86db speakers

I'm sure you didn't mean it that way, but I really dislike the word CHEAP when naming a product that is actually quite nice. Perhaps "inexpensive" or "That I found good at the bargain-priced, yet wonderful PrimaLuna Monos that cost half as much.".

 

[KeithR]

yes, "inexpensive" is a better term. apologies!

 

[microstrip]

Thanks for the insights! Very interesting. I may try to contact a Zanden dealer to hear...most curious.

Curiosity killed the cat ... Are you sure that an audiophile has nine lives, sorry, system opportunities?

 

[LL21]

Curiosity killed the cat ... Are you sure that an audiophile has nine lives, sorry, system opportunities?

Curiosity will not get the better of me...i enjoy my system as it is. It has been the system which i have targeted carefully for over 5 years, and i am happy with it. I simply always enjoy learning more. Given the power capabilities of the Gryphon, i have no desire to change it. Plus, the entire system has been built carefully to the sound i enjoy. The only reason i would replace the Gryphon is if it broke and became unreliable.

Nevertheless, i am a BIG Zanden fan and would love to be able to say i have spent some time with their monos.

 

[microstrip]

Not the same topic at all Tom. I'm not discussing how SS amps that measure somewhat close sound so different. This is more about a tube amp that is sold as a 75 watt amp at 0.6 THD and it doesn't come close to meeting those specifications and why in spite of that, it's still a damn good sounding tube amp.

The sound quality is something much behind a THD figure or a simple THD spectrum. If you listen to this 75 watt amplifier in non clipping conditions using a 84 or a 94 dB/W efficient speaker at the same sound levels you will notice that the most characteristic qualities of its sound show in both speakers. And due to very different powers involved the THD will be very different in both cases, perhaps having variations of an order of magnitude. BTW, this is also true for many SS amplifiers.

 

[mep]

maybe the speakers you heard were the more defining characteristic at shows, not the amp. NOLAs in particular have a really "unique" sound that i found good on cheap Primaluna monos (cost half as much as a Ref 75)

when I moved to high efficiency speakers, it was much easier to tell signficant differences on amplification..and that's because i'm hearing way more than before on 86db speakers

How would you define the "unique" sound of NOLA speakers?

 

[KeithR]

How would you define the "unique" sound of NOLA speakers?

open baffle (well, semi)

 

[mep]

open baffle (well, semi)

and that means...

 

[Steve Williams]

Curiosity will not get the better of me...i enjoy my system as it is. It has been the system which i have targeted carefully for over 5 years, and i am happy with it. I simply always enjoy learning more. Given the power capabilities of the Gryphon, i have no desire to change it. Plus, the entire system has been built carefully to the sound i enjoy. The only reason i would replace the Gryphon is if it broke and became unreliable.

Nevertheless, i am a BIG Zanden fan and would love to be able to say i have spent some time with their monos.

IIRC Zanden makes a 60 wpc amp that puts out reference level sound

 

[Groucho]

If an amplifier is into the 3%-10% distortion region is this not what musicians call "valve overdrive" and is a highly sought after guitar effect that is supposedly pleasing to the ear?

For example http://www.dawsons.co.uk/blackstar-ht-drive-valve-overdrive-effects-pedal

The Blackstar HT-DRIVE has dual cascaded, high voltage, triode stages which deliver gain from warm boost to screaming valve saturation.

Your amps are probably just at the "warm boost" stage. It should sound quite nice.

 

[mep]

Guitar tube amps and home stereo tube amps are designed and built with two very different objectives.

 

[LL21]

IIRC Zanden makes a 60 wpc amp that puts out reference level sound

Yes, i will be hearing them this weekend. In fact, the Zanden 9500 Mk III is the 60 watt Class A amp, that now has been slightly boosted in power to 100 watts in the superceding 9600 mono. I have spoken with a handful of people who have heard this amp...and universal praise the summary. Will post.

 

[microstrip]

If an amplifier is into the 3%-10% distortion region is this not what musicians call "valve overdrive" and is a highly sought after guitar effect that is supposedly pleasing to the ear?

For example http://www.dawsons.co.uk/blackstar-ht-drive-valve-overdrive-effects-pedal


Your amps are probably just at the "warm boost" stage. It should sound quite nice.

Mine are not, I can assure you. My system is calibrated for power and a 0 dB signal track played at my usual volume levels never exceeds 26W, although the tube amplifier is specified to deliver 150W bellow clipping. At these peak powers, distortion is bellow .3%.

 

[KeithR]

and that means...

dipoles dude. quite a good explanation of it on the NOLA website. they sound different than any box speaker, by definition.

 

[Phelonious Ponk]

Guitar tube amps and home stereo tube amps are designed and built with two very different objectives.

They are. And they have much in common.

I listen to 325 watts of of A/B power per channel in the near field. Clearly (an appropriate word), I don't have a problem with a few zeros behind the decimal point. But I don't think 1% THD is necessarily an audible problem either. Is that 1% at peak transients or average? If it's average, that doesn't bode well for the transients. That could be a problem.

Why do some people love the sound of tubes even when they fall drastically short of specs and generate what surely must be audible (if indeed that 1 - 3% is average) harmonic distortion? Why do other people like gobs of headroom and super-low (pointlessly low?) distortion? You may as well ask why some people like butterscotch better than chocolate. This much I'm sure of, mep, and given your history in the last year or so, I know you are as well: They sound different. Make your choice and enjoy.

FWIW, I conceded that specs are not measurements...or at least not all measurements, they're certainly derived from measurements, verified (or not) by measurements....but I'm not sure I've ever heard of a product falling so short of its specs. At least not one that is supposed to be a quality product.

Tim

 

[DonH50]

I thought the W. Klippel study was the subject of some debate? Especially the THD vs. IMD levels since that ran (runs) counter to what has been taken as gospel for some time before? Not really sure, let my AES membership lapse long ago...

I agree with Bruce, Tom et. al. on possibly a defective amp or poor specsmanship. I was trying to address the "why does it sound good" question rather than why it measured so poorly, at least as far as max power output.

I have found far more variation in the sound of tube amps than SS, and have always attributed much of the difference to the speakers. Their high output impedance makes tube amps quite sensitive to the speaker's impedance, for better or worse.

 

[microstrip]

I dont suppose the "I trust my ears over specs brigade" has any problem with the ears inablity to distinguish gross distortions of the orginal recorded signal as the IMD implies.....or the "we are measuring the wrong things brigade" is also OK with such huge discrepancies of the recorded signal.

Tom,

I would love to know what the "I trust my specs over my years brigade" and the "we are measuring the correct things brigade" really believe. A few of them openly claim the non audibility or insignificance of the so called small differences between amplifiers having decent specifications, but what are the beliefs of the others?