Choosing an amp on the basis of tone.....

[NOSValves]

Well now we have the Specs of this super Pioneer.... so how does it sound?

[cjgeraci]

cjg - what exactly is driving your modded khorns? The QSC PLX1202? Seems a chunk here have this. I'm curious about it.

Lisa, I rotate my amps throughout my system. Yes, right now, a QSC is on my Klipschorns (with a Dynaco Stereo 70 on my rear Belles). I first learned about the QSC PLX from talking with Dean about his experiences with the Peach/QSC combination. For everyday use at lower to middle volumes, I probably prefer a nice push-pull tube amp like Craig's VRDs or my Marantz 8B due to the richness in sound, layering and soundstage that the QSC cannot match.

But..........the QSC is pretty surprising for a solid state amp - and especially given its low price and even more so when paired up with a tube pre. At lower volumes, it is quite musical for a solid state amp and while it does not quite have the sonic qualities of some of my favorite tube amps, it sounds good enough to live with on a daily basis (and I have for stretches). Not nearly as dry-sounding as some solid state amps and with much more texture than most. In fact, Sheltie Dave and I DJ'd an outdoor high school reunion (his wife's alma matter - all girls school) using my Peach, a QSC PLX, a cheapo CDP, and a pair of Vertical Cornwalls - all at low to moderate volumes. Many there commented just how great (and musical) the combination sounded- unlike what they were used to hearing at a similar event.

At higher volumes is where the QSC really shines. As the volume increases, the QSC maintains its composure and unlike most solid state amps, it does not pin your ears back at higher volumes. The volume increases cleanly to higher levels but without the "glare" (and pain) that most solid state amps bring. At the highest volumes, the QSC PLX is surprisingly "tube-like" in its sound, which is a compliment to its tube brethren. And without getting into specifics, lets just say that I have gotten into the QSC volume-wise pretty nicely into its power band, and it performs cleanly all the way up.

Used QSC PLX 1202s have gone for about $400 on ebay, which is the average amount that I picked up my two QSCs.

One final note. The QSC PLX does have a fan, but even in an open rack - you cannot hear the fan unless you have music (or movies) at whispering levels.

Carl.

[Guest " "]

I had one a few years ago when I was in the service...the sound was amazing.

[pauln]

Specs that include exclamation marks? Exciting visible "innerds"?

That ad copy is exactly what appeals to those who subscribe to the specs = sound tribe.

So yeah, how does it SOUND?

And why does it say (twice) that it had a total of 44 transisters and 66 diodes for a (surprise) total of 110 semiconductors? Are they implying more is better, or that we can't do the addition ourselves, or that we can't remember it without repeating?

[DrWho]

How do you know which is a more realistic interpretation without

comparing the recording against the real live sound that was recorded?

Or at the very least comparing against what was heard in the studio?

Comparing amp A against amp B tells you nothing but the differences

between A and B. It doesn't tell you which is closer to the real sound.

Should I mention that PWK was very adamant about this point?

It sounds to me like the reviewer of the expensive SET amp has

noticed a flaw in the recording and simply came across an amp that

masks that flaw. I don't care if even harmonic distortion is pleasing

to the ear, it still imparts a different sound. Nor do I care that 12dB

of gain at 80Hz sounds pleasing - again it's imparting a difference on

the sound. These are differences that will not change as the source

material changes. After a while this gets boring and fatiguing and

really ruins the sonic experience for me. If it doesn't ruin the sonic

experience for others then I envy them and wish them well on their

audio journey. It is no different than saying you like a distortion box

inline with the signal path.

Granted no component in the system is perfect and we must choose

a system synergy that imparts the least amount of displeasing

artifacts. However, this does not justify an intential

misrepresentation of the signal. When the system fidelity exceeds that

of the studio fidelity, then any improvements in the accuracy of

playback should increase the audibility of flaws (aka, sound worse).

Only after this point can one choose to attempt to undo the flaws in

the studio by imparting intentional deviations from accuracy. OR one

can choose the route of accuracy and be more selective with the source

material. But in the world of generalities, claiming that deviations

from accuracy is the ideal approach seems a bit far-fetched...

Since I'm in favor of the scientific method, I think it would be

an extremely vital asset to the industry to quantify when deviations

from accuracy are a good thing. Instead of all this arguing about

trying to make globally true generalities, why not quantify deviations

that go well together? Like old music, tubes, and vinyl?

Just for the record...there is nothing inherant with tubes that causes there to be even order distortion, nor SS that causes there to be odd order distortion. I wish I could remember the website, but some dude ran out and measured a crap load of amps that showed no correlation. In other words, there are SS amps that have even order harmonic distortion too...Maybe someone else is familiar with the website and can post it.

[Allan Songer]

"old music, vinyl and tubes"

So?

[joshnich]

Atta boy Allan. Could not have said it better.

For the record, I have never owned an oscilloscope, and do not use them to determine my enjoyment of music; I would humbly suggest that anyone who wants to argue facts understand that the only facts that matter are that it sounds good. I do not know if a 1-watt amp sounds good but would have to say that I couldnt agree that it doesnt. My ears are my ears and they are no one elses.

I am happy to play my music and happy to think that it sounds good- regardless of the so-called facts or the measurements on some piece of equipment!

Regards

Josh

[DrWho]

"old music, vinyl and tubes"

So?

I wasn't trying to imply anything...just too lazy to list out a bunch of other combinations (like electronica, digital, and SS, or whatever other infinite combinations found on the board).

[NOSValves]

Atta boy Allan and Josh,

No one can tell someone else what sound good to them. We can only share what sound good to us, with are own ears, room, gear, wire, sources and the music we enjoy! If We the individual are enjoying what we hear what the heck else is important? That said I do think blanket recommendations on high powered, low powered, mid powered, SS, tubes, digital .....you name it are all over stated by just about all of us at one time or another.

Lets bury this subject in a huge very deep hole and start 2007 anew around here. It is just plain worn out from all angles.

By the way SET sucks and all these SS and Digital guys are deaf[] Just kidding folks.

Craig

[meagain]

CJ - Thanks much for the nicely detailed post on the QSC PLX. I've saved it.

[Guest " "]

"And why does it say (twice) that it had a total of 44 transisters and 66 diodes for a (surprise) total of 110 semiconductors? Are they implying more is better, or that we can't do the addition ourselves, or that we can't remember it without repeating?"

I moved the paragraph that had the bandwidth and signal to noise ratio up to the top. I doing so, the line about the semi-conductors got pasted twice.

What makes this amp a marker of achievement in my mind is the incredible signal to noise ratio, 106 db. You heard of vanishing speakers...well this is a vanishing amp.

[NOSValves]

You heard of vanishing speakers...well this is a vanishing amp.

I'm not sure if I'm losing it or what. But that line really made me giggle!! Was this amp known to get stolen it was that good[]

[maxg]

The original title of this thread is "Choosing an amp on the basis of tone". This appears to be EXACTLY what SET lovers (although not uniquely) do.

Jeff,

I am not sure if it has been spelled out sufficiently - but at the volumes you are listening to the distortion from the amps is not the problem. You are at the limits of the speakers and these will distort the sound horrendously- whatever is driving them.

I would suggest that if you want to listen this loud - stay with the Crown - it does the job. Alternatively - take a forray into car audio - car systems can reach 160 dB+ so you can really rock out (and thank God you are a continent away from me).

[pauln]

Just for the record...there is nothing inherant with tubes that causes there to be even order distortion, nor SS that causes there to be odd order distortion.

Dr Who, I guess they don't teach tubes nowdays but you can catch up by reading this... http://www.nutshellhifi.com/library/tinyhistory1.html

A sample

Seventy years later, vacuum tubes, and especially triodes, continue to be the lowest distortion amplifying elements ever made. No germanium or silicon transistor, JFET, or MOSFET has ever approached the distortion performance of the direct-heated triodes, with indirect-heated triodes following closely behind. In addition to low distortion in the absolute sense, the distortion spectra of triodes is favorable, with a rapid fall-off of the upper harmonics. (This is less true for beam tetrodes, pentodes, or solid-state devices, which are intrinsically less linear and have higher-order distortion curves.)

[DrWho]

let's see some measurements

[fini]

The original title of this thread is "Choosing an amp on the basis of tone". This appears to be EXACTLY what SET lovers (although not uniquely) do.

Jeff,

I am not sure if it has been spelled out sufficiently - but at the volumes you are listening to the distortion from the amps is not the problem. You are at the limits of the speakers and these will distort the sound horrendously- whatever is driving them.

I would suggest that if you want to listen this loud - stay with the Crown - it does the job. Alternatively - take a forray into car audio - car systems can reach 160 dB+ so you can really rock out (and thank God you are a continent away from me).

Max,

When I listen to music that's too loud for me, my ears/brain distort the sound as well.

[Jeff Matthews]

CJ - Thanks much for the nicely detailed post on the QSC PLX. I've saved it.

Lisa, the VRD's you have equal that QSC in terms of slam/punch. You're done. Stop looking.

[dhtman]

A perception machine? Maybe so. It's already been acknowledged in this thread that people prioritize differently when buying audio. I'm always amused when I visit an audio show to stumble on a room, usually selling single driver speakers, where there's a bunch of men (and it is always just men) leaning forward in their seats, straining to hear a solo violin or classical voice at whisper quiet levels. I know that SET amps and single driver speakers do some things very well, but for me, the compromises are unacceptable.

Having waded through the twists and turns of this topic, here's my attempt to answer the question.

My first criterion when listening to an audio system is "Do I feel like I'm listening to a performance here?" I'm not concerned about the level - I'm happy to listen at about 82dB in my listening seat. I want the voices and instruments to sound realistic, the drums and cymbals to remind me of being at a live gig, and I want to hear good separation of the bass guitar and kick drum and sense that I'm hearing with my body, not just my ears. Experience is teaching me that a pair of very good speakers is more significant in eliciting this feeling of a performance than the amp in use. I suspect that the interaction of the amp and speakers' crossovers has a large bearing on presentation. I am turned off by bass that rolls off too high and anomalies in the mid range.

So we have accuracy (I guess relative rather than absolute) of tone and timbre as my priority, then there's the sense of dynamics - hearing the initial strike of plectrum on strings or drumstick on snare - is that believable for me? And closely related, is the decay of notes credible? And on complex passages, when it all gets busy, can I still follow a rhythm guitar line or the keyboard fills? There's a Supertramp track with sax and lead guitar playing in unison that less adequate systems blend into one.

Closely related to the dynamics, is something I struggle to put into words, it's a perception of passion, the musicians performing at the peak of their powers, sensitive to what each other is playing. This is something I notice most when listening to jazz, the way the band pick up on the soloist's tempo and phrasing. Some amps I have heard (or more accurately amp/speaker combinations) tend to mask or lose that sense of immediacy, others portray it really well. This could be what reviewers call "timing" but I'm not certain that's what they mean, but I remember hearing some very expensive SET amps through Avant Garde Trios that made some great recorded performances sound pedestrian.

If we're still doing okay, next, how long can I listen for before I've had enough? Tube amps score well on this for me - is that the absence of grain that Mark refers to near the beginning of this thread? About 10 years ago I had a Naim pre/power combination. I found that within a few months I was listening for shorter sessions and then less frequently, I believe a subconscious reaction to fatigue. I think it's important to have an extended trial of any new amp.

SET amps do have a purity and intimacy about their presentation and I have had some great results with my 300bs driving Tannoy speakers, however they wouldn't be my recommendation for listening to rock music. Whilst 300bs have reasonable power output (8 watts) the bass is softish and (in my experience to date) 2a3s and 45s lack the outright power to do a proper job on transients, even on high efficiency speakers (in my experience). Maybe KT88s triode-strapped really is the best compromise? I don't know.

I spent about 45 minutes in the Boulder room at RMAF. They were using Wilson Maxx speakers (that's an ugly brute IMO) and whilst the system was quite convincing on orchestral pieces, there was something not quite right about the presentation - it was almost too pristine and synthetic, so I guess that's me reacting to the tone of the system. So there's something about the overall listening experience - akin to the sum being greater than the individual parts.

One additional observation. I have kept most of the amps I've owned in the spare bedroom (well you never know when they might be useful!) I'm gradually clearing them out on ebay. When I put a Pioneer A400 into my system to check it stil worked, I was initially quite surprised at how good it sounded. It handled a few of my test tracks quite convincingly and the buyer was happy when he collected it. However, going back to my regular amp, there was a noticable improvement in clarity, like removing a gray metallic sheen.

So no real conclusions, and I'm clearly not swayed by the same things as a Stereophile reviewer (I believe that reviewers listen out for a characteristic "hi fi" sound that bears little relationship to how real music sounds). But the perception I experience has to tap into the kind of feelings I experience when I'm hearing music played live.

[Parrot]

It sounds to me like the reviewer of the expensive SET amp has

noticed a flaw in the recording and simply came across an amp that

masks that flaw. I don't care if even harmonic distortion is pleasing

to the ear, it still imparts a different sound. Nor do I care that 12dB

of gain at 80Hz sounds pleasing - again it's imparting a difference on

the sound. These are differences that will not change as the source

material changes. After a while this gets boring and fatiguing and

really ruins the sonic experience for me. If it doesn't ruin the sonic

experience for others then I envy them and wish them well on their

audio journey. It is no different than saying you like a distortion box

inline with the signal path.

Amen, brother. There is no way the $350,000 SET amp under consideration can be considered accurate, even close to accurate. Now, I wonder how many minutes will elapse before someone claims that there is no such thing as accuracy? Or that a cheap solid state amp is accurate but sounds bad? Well, an amp designer should take a stab at accuracy, and a $350,000 SET amp that adds 12dB at 80Hz is absurd.

There are gizmos that allow the user to add as much "tube sound" as he desires in his system. The advantage of adding such pleasant distortion is that the user can tailor it to the recording. The $350,000 SET amp, as you point out, adds that to everything, an intentional misrepresentation of the signal, as you put it.

As Max points out, it does seem like at least some SET owners pick their amps for their tone. But this is like looking through color-tinted glasses--it makes everything you see color tinted. Remember the blue-blocker sunglasses, that would make everything you see look better than with your naked eye? It was a fad that got tiresome quickly.

[Deang]

The end of this thread is a lot better than the beginning!