FWIW, just a short story about how things can change. 30 years ago I had two high power tube amps with SED KT88's. Bought a backup set (or two). Sold amp. What to do with tubes. Nothing, I just put them in a big drawer. Pulled them out every few years and always found them powerful but a tad bright. Never got an amp which served them well and I kinda forgot about them.
I got old. Needed new KT88's. What the hell, I pulled out the old SED's. Interestingly (to me at least) the upper frequency retained its clarity but what was bright in yesteryear, now matched the natural loss of some high frequencies in my hearing due to age. Hog heaven!
Point, if any, to this story is when you go out to buy tubes don't forget that the sound of tubes can and will vary because of the hearing of the seller as well as his knowledge of how they will sound in your system.
Yes. Look at distortion vs frequency- if it begins rising much below about 10KHz you will have a brightness problem since higher ordered harmonics will be higher than the THD suggests.
The other thing to look at is the distortion profile. Smoother sounding amps have a greater degree of 2nd and 3rd harmonic than amps that tend to sound bright and harsh. This is simply because the 2nd and 3rd in the latter amps is insufficient to mask the higher orders. Our ears interpret the higher orders as harsh and bright using the same metrics that cause tone color in musical instruments.
Ralph...this makes me want to if there is a level of distortion below which the increase in THD+N doesn't really matter as far as harshness is concerned?
Some examples might be the Pass XA25 where THD+noise starts to rise at 300 hz but starts from a level of .0015 and then hits .01 by 5khz and .02 by 10khz. Or, another example could be the Benchmark AHB2 where the increase doesn't start until 2khz and starts from .0004 and rises to .001...or the NAD 298 Purifi where the increase starts at 7khz and rises from .003 to .01. (All from Stereophile measurements).
None of these amplifiers are usually described as harsh (although some feel the AHB2 or the NAD may be a little sterile)...and yet they all have increasing THD+noise starting below 10kz...and all are predominantly 3rd harmonic dominant.
So, is it possible that if the increasing THD+distortion starts below 10khz...but is at a low enough starting point and is predominantly 3rd harmonic, then the sound might not be harsh...or am I missing something else that could explain this?
The scientific method requires a theory followed by testing, with reliable results to prove the theory. Without testing, measurements are not necessarily significant. You need a real life A/B comparison.
And on a related note, what measurements - if there are any - show the difference in sound between SS and tubes?
Could one see this on a frequency chart?
Yes. Look at distortion vs frequency- if it begins rising much below about 10KHz you will have a brightness problem since higher ordered harmonics will be higher than the THD suggests.
The other thing to look at is the distortion profile. Smoother sounding amps have a greater degree of 2nd and 3rd harmonic than amps that tend to sound bright and harsh. This is simply because the 2nd and 3rd in the latter amps is insufficient to mask the higher orders. Our ears interpret the higher orders as harsh and bright using the same metrics that cause tone color in musical instruments.
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Thanks that's very interesting. So we can sort of measure these subtle differences but not really. And is the binaural nature of hearing ever part of it? The subtle phase differences of stereo?
@llg98ljk Keep whipping that dead horse repeated by ss fans ad nauseum.
Maybe you didn't pay attention to my post. I'm whipping no horse, dead or alive. My point is simply that audio perfection would mimic the source. The technology is irrelevant to the discussion. Many people spend inordinate amounts of money and time chasing a sound using a very imperfect instrument. Their ears.
I've been playing this game a long time, like back when Vandersteen had only two models....really one, but officially two. Anyway, my hearing back then was stellar, but after a lifetime of live sound, shooting sports, and other high SPL events, I have light tinnitus, and a definite disparity between right and left ears. So I realize I have ultimate limitations, but I also realize that my lifetime of critical listening has helped to overcome some of the actual loss. I still hear new things in familiar recordings.
Concentrate and enjoy the moments, they're still there.
I’ve been running tubes since about 1973. I used to retube my ARC SP 3-a-1 with period Telefunken 12ax7s which were about 10 bucks a tube. Finding true unused ones from the ’60s or ’70s is not impossible but they are expensive now.
Everything I run is tubes except for the home theater. (Even that was three ARC tube amps at one point until I decided it was stupid).
My vintage system uses a matched quad of GEC KT66s from the era. Not easy to find and if and when, might have to be replaced with a modern production tube.
The line stage in the main system only likes period DR 6h30s, a tube that is very scarce.
The rest I source from Lamm (for the amps), Allnic (replaced all the audio circuit tubes with Holland Siemens). I roll the rectifier in that, and have a bunch of grail tubes- I like the GEC u-52 in my system, given how it voices.
I’m no tube guru. I rely on trusted vendors. Andy is the best, but he’s slow and old school. I’m not buying bulk- but want enough to have back ups.
Tubes are truly a pain in the ass these days, given sonics. More power to you if your gear sounds good on modern production tubes. I’ve found that I do better with other, older tubes, and that’s where you wind up going down the rabbit hole.
Measure using technology, science and an understanding of how the ear/brain works ( over long and short periods ), AND listen ;-)
We have always had tipped up speakers… long long before we had aging Audiophiles… why ? short term easy sell…. but doing zip to advance accuracy in music reproduction….. like many flavorizer products out there….
Knowing what kind of distortion you like is sign of an excellent audiophile…..
And on a related note, what measurements - if there are any - show the difference in sound between SS and tubes?
Could one see this on a frequency chart?
Yes. Look at distortion vs frequency- if it begins rising much below about 10KHz you will have a brightness problem since higher ordered harmonics will be higher than the THD suggests.
The other thing to look at is the distortion profile. Smoother sounding amps have a greater degree of 2nd and 3rd harmonic than amps that tend to sound bright and harsh. This is simply because the 2nd and 3rd in the latter amps is insufficient to mask the higher orders. Our ears interpret the higher orders as harsh and bright using the same metrics that cause tone color in musical instruments.
Start by looking at the distortion profile of an SET. That will give you an idea of the relationship of the 2nd and 3rd harmonics to the higher orders, so you can start to see what you're looking for in the measurements.
BTW you don't need the 2nd harmonic- the ear treats the 3rd very much as the 2nd as long as its not too profound. But it needs to be more profound on a percentage basis than the succeeding harmonics in order to mask them.
We've had the tech to measure this stuff for about 30-35 years but the understanding of the significance has been lagging. So we now have a direct link between measurements and what we hear. Unsurprisingly, these measurements can be a bit hard to dig up...
Along this line, it has been stated by someone whose opinion I trust, that many high end speakers are bright at the high end because the target market is older, affluent individuals who have hearing loss at the upper end.
So shop for speakers that are certified flat (unless you have hearing loss).
If you think about it, despite all the noises on forums, chasing the audio holy grail has little to do with "perfection". It has everything to do with what you think you want to hear.
One of the best examples to me is tube equipment. Many people swear by tubes and scoff at solid state. Why? because it has distortion that people like. The best possible system would be the "straight wire with gain" type. What goes in comes out unadulterated.
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