Which amp specs really matter?

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I just wish the tube guys were honest with their specs they do publish. A tube amp with a low damping factor driving a speaker with a very complex impedance curve, performs very poorly. But they won't publish that. SS amps do so much better. Sure amps with low feed back over shoot, ring, and are edgy. That's not real to life music, thats what is found in recording studios with gimmick machines to make the sound to a producers liking, not real sound, not authentic sound, not natural sound, not something your ears can tolerate for hours and hours . Some acoustical instruments are hard on the ears in the first place. We don't need electronics that make them even more irritable.
 
Simple: If the manufacturer states something like 0.001% distortion, but doesn't say at what frequency or at what level, its just a meaningless number. Depending on the feedback topology it is "always" ameaningless number.

Or speakers / headphones:
One is specced 5 - 35 KHz
The other speaker 45-19KHz +-3dB

Which would you buy? And why?

No good way to select one if this is only info given. Your point is easily understandable. Must have qualifiers to these "specs"
 
Given that the thread has devolved into a "mine's better than yours" exchange, I thought I would still respond.
I don't mean to be rude or anything, but I simply don't grasp your point as it relates to my original post. Sorry.
Perhaps I'm just not properly reading for comprehension or something.

Cheers
No ulterior motive, I just want to know which specs govern those specific functions I mentioned. You're an EE, right? Don't mean to take you to task. I would just like to know.
 
No ulterior motive, I just want to know which specs govern those specific functions I mentioned. You're an EE, right? Don't mean to take you to task. I would just like to know.

OK, I think I understand what you are alluding to. If you want parametrics for largely subjective impressions, I'm sorry - you'll need to find someone else to tackle that bit of voodoo. My stated preferences for specification evaluation in regards to power amplifiers are just that - my preferences. They may be unimportant to the next guy and that's fine with me - whatever floats your boat. Your interest in how an amplifier performs no doubt differs from mine as I'm sure our total system objectives differ.

And another response -EV13
>>"Simple: If the manufacturer states something like 0.001% distortion, but doesn't say at what frequency or at what level, its just a meaningless number. Depending on the feedback topology it is "always" ameaningless number.

Or speakers / headphones:
One is specced 5 - 35 KHz
The other speaker 45-19KHz +-3dB

Which would you buy? And why?"<<

I think you are referencing THD, if not I'm not sure what distortion you mean. If you did mean THD, stating that it is "always" a meaningless number throws an awfully broad blanket. Granted, most manufacturers do not state how they test to determine the value and amongst manufacturers it is not simple to make valid comparisons. At the very least, it casts some light on the performance if it's coming from a reputable manufacturer - not much light, agreed despite whatever topology is used.

As to the speaker/headphone specs - neither of your listed items inspire any sense of confidence. Is it on-axis response? Is this an anechoic value? I'd rather see a graph of full power bandwidth with conditions.
For headphones, it would be another can of worms. I think you missed my first post, #41. I noted, that without test conditions including stimuli, most specs have little value.

Cheers
 
Voodoo? Are there not specific specs that govern certain subjective characteristics? Was it not the purpose of the op to discover such? Surely there are certain specs that can be referenced in verifying subjective evaluation, no?
 
I'd buy an amp from a mfr who had the nads to announce 0.5% or more THD and who declared that other things are more important.

Definitely agree with the observation upthread that the price paid for too many places to the right of the decimal point is too high.

Did I already say this in this thread? Oh well, can't be bothered to look. Personally, if I had to choose, I like the S/N stat.

But overall my response is "none of the above" and I prefer listening to music to studying numbers.
 
It is a matter of taste. I don't want distortion, euphonic or otherwise. I suspect that EStat does. Do you? Do you acknowledge that taste is important? There are many that, like me, don't want the amp to alter the music.

Shelly_D

I have to disagree. Run some special listening tests using the amp in question as a preamplifier (or a preamplifier as a preamplifier), being able to switch in and out of the system, and one will discover how inaccurate an amplifier (or preamplifier) really is.

Specs don't mean that much, except power, sensitivity/number of stages, frequency response (some are very poor). Distortion is so variable, which harmonics, what power, what frequencies etc.

The ear has to be the final judge since there are so many variable aspects to deal with.

Keep on truckin
Joe
 
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The were as overdamped as any of the classic AR products, and they were insensitive and meant for higher power (e.g., pp 7195, EL34, or "kinkless tetrode") amplifiers. Indeed, AR recommended 25 watts minimum for the AR-3.

ar_loudspeakers_early_19-14.jpeg

12 watts output is only 3db less than Suggested 25 watts. Depends upon the room size as well. What SPL were they aiming for when giving the spec?

Keep on truckin
Joe
 
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I think you are referencing THD, if not I'm not sure what distortion you mean. If you did mean THD, stating that it is "always" a meaningless number throws an awfully broad blanket. Granted, most manufacturers do not state how they test to determine the value and amongst manufacturers it is not simple to make valid comparisons. At the very least, it casts some light on the performance if it's coming from a reputable manufacturer - not much light, agreed despite whatever topology is used.

As to the speaker/headphone specs - neither of your listed items inspire any sense of confidence. Is it on-axis response? Is this an anechoic value? I'd rather see a graph of full power bandwidth with conditions.
For headphones, it would be another can of worms. I think you missed my first post, #41. I noted, that without test conditions including stimuli, most specs have little value.

Cheers


This is such a problem online, or possibly a personal one of mine.

I try to explain something in simple terms to get the basic idea across and the next dude comes in and waves his crossover distortion and HRTF flags at me.

:)
 
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I'd buy an amp from a mfr who had the nads to announce 0.5% or more THD and who declared that other things are more important.

Definitely agree with the observation upthread that the price paid for too many places to the right of the decimal point is too high.

Did I already say this in this thread? Oh well, can't be bothered to look. Personally, if I had to choose, I like the S/N stat.

But overall my response is "none of the above" and I prefer listening to music to studying numbers.
My Boothroyd Stuart Meridian 105 monos circa 1978 only state 100wpch min. with no more than .1% THD, .01@ 1Khz. No bragging rights with that except that they were sota then and even now don't take a back seat to anything in terms of sq.
 
12 watts output is only 3db less than Suggested 25 watts. Depends upon the room size as well. What SPL were they aiming for when giving the spec?

86 dB (IIRC) and 4 ohm. Clearly not the friendliest of speakers to modestly powered tube amplifiers, otherwise okay if you didn't push it.

12 watts won't go very far with a pair of AR3s.
 
Practically speaking, which of the advertised amp specs do you look at when buying, or, in your experience, make the most impact on your listening experience? I understand they may each contribute to different elements of the sound...

The ones that make sense to me:
- frequency response range
- S/N ratio
- damping factor
- total harmonic distortion

And I can barely make head nor tail of the others.


None of the above. Like the old saying, numbers don't lie but liars do figure.

The measurement I use to start things is weight. How many pounds? Me, I start at 50 or 60 as a minimum. Big class A amps do not weigh in at 30 pounds. Closer to 130, actually.
 
For me specifications are not that important. Other peoples opinion and my own ears is what matters to me.
What I do look at is weight and RMS (preferably in 8,4,2 ohm). Transformers and large heatsinks carries a lot of weight. The RMS at different ohm:s give an indication of the amps ability to drive difficult loads. Other than that I think it´s a crap shot. This applies for SS, tubes is a whole other can of worms :)
 
In my world an amplifier's output impedance is as relevant a specification as any.

Most audiofools including many on this forum will sentence an amplifier to death by analysis without ever making the slightest attempt to actually hear it in situ.
 
Friends,

I appreciate all the replies on this thread. It's been very valuable getting a sense of the different attitudes and perspectives on specs, and more interestingly, on the deeper question of what really makes an amp sound 'good'. I took E-stat's advice with only a grain of salt, but a recent experience has humbled me a bit and made me realize how deep the rabbit hole goes.

Let's examine the following amps.

Technics SA-424
Frequency response: 5Hz to 80kHz
Total harmonic distortion: 0.007%
Damping factor: 40
Signal to noise ratio: 82dB (MM), 98dB (line)

NAD 3020 (I recently re-capped mine)
Frequency response: 10Hz to 70kHz
Total harmonic distortion: 0.02%
Damping factor: 55
Signal to noise ratio: 75dB (MM), 110dB (line)

Sherwood S-7100A
Frequency response: 30Hz to 20kHz
Total harmonic distortion: 1%
Damping factor: 30
Signal to noise ratio: 65dB (MM), 75dB (line)

By these 'measurements', the Sherwood looks the worst. I almost didn't get it because of this (though I was curious, and couldn't resist, for a mere $30). I built a makeshift speaker switch box from a cheap A/V switch (no, it was not break-before-make, and I understand the dangers of that, but it gave me the opportunity) to switch between the amps on the same set of speakers without the tedium of constantly changing wires. I performed a blinded test, with the begrudging help of my roommate.

Indeed, the Technics made noticeably less noise at the same volume compared to the other two units. It was clean and crisp in the high ranges. But much to my shock, the Sherwood blew the other two amps out of the water (though the NAD performed quite well, and noticeably better than the Technics). Despite the higher THD (which the human ear is quite apt at adapting to), the music simply sounded better, richer, more rounded and warm. I could hear notes, nuances, and occasionally instruments that I could not hear before! It was as though I had wiped a layer of dust off my glasses and opened my eyes to a richer sonic world. I enjoyed No Count Sarah Vaughan as though I was hearing it from the first time. And it felt so lifelike and sonorous - so true to the beauty of her artistry - that I couldn't help but get up and dance to the music.

Needless to say, I'm proud to have the Sherwood as the current centerpiece of my system. There's a reason the vintage amps have such a reputation, and I definitely better appreciate now that hearing is believing (coupled, perhaps, with an informed understanding of the contribution of specs to that particular amp's performance).
 
I keep wondering just how many people prefer "analog and/or valve "warmth" over precision.

It does sound awesome. Maybe this is the origin of "digital can be boring".
 
I keep wondering just how many people prefer "analog and/or valve "warmth" over precision.

It does sound awesome. Maybe this is the origin of "digital can be boring".

I never found accurate, precision listening to a live event (no mic), to be boring. I find it beautiful and often awe inspiring. Maybe just me?

We must remember that the 3 distortion specs listed are at maximum power, but extremely low at one or two watts, which is often "normal" volume for folks.

keep on truckin
joe
 
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