Andre Visser said:
It is probably easier to do it the other way around. Unless of course you are talking about some of the "squishy" tube amps inspired by the classics.
dave
Hey Dave - I agree with your post #200. But aren't we mostly talking about damping factor here?
You can really change the tonal balance of a low Qts driver with some series resistance or a higher amp output impedance. It's a lot less effective on high Qts drivers, right?.
That why I'm interested in helping to design an amp test or tests and what would need to be specified. Isn't anyone else? There is plenty to argue about there, if you like to argue.
Anyone?
Let's take the OP as the starting point.
You can really change the tonal balance of a low Qts driver with some series resistance or a higher amp output impedance. It's a lot less effective on high Qts drivers, right?.
That why I'm interested in helping to design an amp test or tests and what would need to be specified. Isn't anyone else? There is plenty to argue about there, if you like to argue.
Anyone?
Let's take the OP as the starting point.
I dont agree that its so difficult with amp-speaker-cable mating
A second grade amp will need that mating, but a top class amp will sing along no matter what...and a MarkLevinson is NOT in that category
It goes without saying that special flea amps will need special mating and too difficult to fit in such a test...I rate fleaamps to be kind of a shortcut to good sound, although the whole setup will need to be built around such small amps
Needless to say that I belive the amp to be one of the most important components i any setup...I am not sure I dare say the most important component
A second grade amp will need that mating, but a top class amp will sing along no matter what...and a MarkLevinson is NOT in that category
It goes without saying that special flea amps will need special mating and too difficult to fit in such a test...I rate fleaamps to be kind of a shortcut to good sound, although the whole setup will need to be built around such small amps
Needless to say that I belive the amp to be one of the most important components i any setup...I am not sure I dare say the most important component
jcx said:
This begins by stating that
Regrettably no pertinent details are given so it is not conclusive though certainly suggestive that all good amps don't sound alike.
I have to add that I grew up with tube amps and just plain dislike the technology so I would argue that this is not a comparison of good amps; that's why Carver had to down grade his!
(just a joke, just a joke)Andre Visser said:
I agree it doesn't seem to add up and clearly it would not pass muster for publication in any serious journal. It is entirely mute as to methodology and actual results. But it is interesting and my doubt factor on my own position is rising.
Hi Michael.
Start with the goal and then work backwards!
Also plagiarize previous attempts or study for ideas and/or methodology that should be brought forward.
With the talent in this forum, I bet every facet could be covered and a complete and fair methodology can be developed and refined to stand the test of professional scrutiny! Hopefully the ultimate test.
Document and copywrite this. It just may wind up in an article or book or two. What funding for the forum.
Maybe enough for amp festivals that would be free!Goals are good and so are dreams!
BTW, this thread suddenly has a real purpose and I like what I am reading!
Regards//Keith
Start with the goal and then work backwards!
Also plagiarize previous attempts or study for ideas and/or methodology that should be brought forward.
With the talent in this forum, I bet every facet could be covered and a complete and fair methodology can be developed and refined to stand the test of professional scrutiny! Hopefully the ultimate test.
Document and copywrite this. It just may wind up in an article or book or two. What funding for the forum.
Maybe enough for amp festivals that would be free!Goals are good and so are dreams!
BTW, this thread suddenly has a real purpose and I like what I am reading!
Regards//Keith
Lol , I was given a cheap kenwood receiver and a nice big EQ. It is maybe 30-40w/ch so I put it in my garage. Then I find out why the EQ come with it, the thing has no bass at all; you have to run the EQ to get it to sound normal. It works fine out there.
planet10 said:
You mean as in impedence matching elements or as in woo-woo pseudo-quantum phonon phasers? ... Hey, around this stuff ya gotta ask LOL
panomaniac said:
yes damping factor = f (output impedance, speaker impedance). Since speaker impedance is all over the map, damping factor is usually specified with an 8 ohm fixed resistance and like power output into a fixed resistance becomes somewhat meaningless.
You can, but so far i have found that a series resistance subtracts a lot while a higher output impedance amp does not.
dave
eStatic said:
In the sense that you are matching the output impedance of the amplifier to suit the loudspeaker characteristic.
Before the SS amp cam einto vogue it was common for the amplifier to be matched with the loudspeaker. I talked with a very good western electric engineer and they designed the amplifiers so that the output impedance of the amp was equal to the loudspeaker (damping = 1). Both Thorsten Loesch & Nelson Pass have been 2 people bringing back to light the advantages of transconduction/current amsps (damping less than 1). The market, and many in it for the last 40 years or so have had little conept of anything but the strictly voltage amplifier (damping >>1).
All approaches are valid within the context of an entire speaker /amplifier system. Bit use that current amp with a speaker designed assumming a voltage amp (or vicea versa) and it is not going to sound very good.
Now then, how does one compare a very good voltage amp to an equally good current amp?
dave
KP11520 said:
OK, I'm game. But I'm not really sure what the goal is. How about this:
To establish whether it is possible to realiably destingish between the sound of 2 different amplifiers.
But which amps? How do they qualify for testing?
Power catagories?
Damping factor?
Acceptable BW, FR, THD?
These would need to be established first, before the test details.
planet10 said:
Good question. Do these amps need a catagory of their own? Or would speakers be choosen that should sound the same on voltage vs current amps? Or something else altogether?
Plenty of work to be done.
(sorry for the spelling, no speel tchek on this computer)
panomaniac said:
One of the questions is -- where do you draw the line?
Certainly you could create sets of similar amps. But you won't find a speaker that works well with amps from opposite ends of the spectrum. One thing that will happen is that the test would be considered invalid because the FR of the 2 systems would be different.
dave
OK, then. There should be catagories.
But, as you say, where to draw the line? I think we can establish that.
But should there be cross catagory tests, across damping factor and power catagories?
Small power amp fans like to claim their amps sound better than muscle power amps. Do they, on a level playing field?
But, as you say, where to draw the line? I think we can establish that.
But should there be cross catagory tests, across damping factor and power catagories?
Small power amp fans like to claim their amps sound better than muscle power amps. Do they, on a level playing field?
tinitus said:
I agree with you on this although to get the best out of a system everything became equally important.
panomaniac said:
The fact that you have to create different categories for amplifiers proves the point already.
According to me, the people that want to prove that amps sound the same, are those that try to sell or have inferior amps and don't want other to listen for themselves.
Andre Visser said:
André,
thank you for mentioning MUSIC.
To everyone else.
The simple, cheap way to compare, using your ears, is:
- choose a piece of MUSIC about 5 to 10 minutes long
which is harmonically and rythmically complex
with several players or singers to the same part
with wide dynamic range
- listen all the way through via amp. A
- listen all the way through via amp. B
- listen to amp. A again
If there is a significant difference then by now it will be obvious (if you don't understand how this can be, then you need to carry out the exercise using two amps. that you reckon you should be able to tell apart).
If no obvious difference then:
- mark certain points that strike you as particularly good on each amp. (e.g. harp showing through orchestral tutti)
- play through to see how each amp. deals with these "difficult" bits of the piece
You have now done enough.
It is a waste of time doing this using a recording that has been manufactured in a studio to sound good on lowest common denominator music systems.
The alternative is to spend time and money chasing equipment to determine the ever decreasing differences in distortion between amps. and then discovering that it makes little difference to your enjoyment of the MUSIC.
Hope this helps,
Andy
Ps - if anyone is interested then I will post the MUSIC that I use for this process
Test music
Dave,
Tallis - Spem in Alium (40 part motet)
CDGIM 203
Quite a difficult recording to reproduce well. Recorded in a very reverberant acoustic. I now am fairly sure that there are two trebles standing too close to different microphones.
My only SACD: Frank Bridge - Sir Roger de Coverley Chan 5018
Exuberant contrapuntal stuff, well recorded.
Holst - Planets, Perfect Fool NI 5117
Crystal clear playing, recorded brilliantly in the difficult acoustic of the Royal Albert Hall, using a Soundfield microphone. I wrote this comment, then read their blurb, honest!
Bach - Tocatta and Fugue in D minor (there was a time when I could struggle through this piece) for the descending pedal scales.
Hope this helps,
Andy
Dave,
Tallis - Spem in Alium (40 part motet)
CDGIM 203
Quite a difficult recording to reproduce well. Recorded in a very reverberant acoustic. I now am fairly sure that there are two trebles standing too close to different microphones.
My only SACD: Frank Bridge - Sir Roger de Coverley Chan 5018
Exuberant contrapuntal stuff, well recorded.
Holst - Planets, Perfect Fool NI 5117
Crystal clear playing, recorded brilliantly in the difficult acoustic of the Royal Albert Hall, using a Soundfield microphone. I wrote this comment, then read their blurb, honest!
Bach - Tocatta and Fugue in D minor (there was a time when I could struggle through this piece) for the descending pedal scales.
Hope this helps,
Andy
Andre Visser said:
Well... not necessarily.
The most basic category would be power. It is only fair to us an amp within its power range. I don't think anyone is claiming that a 300B SET amp is going to sound like a Crown or QSC driving a concert PA to 112dB at the mix position. (I should know, I've tried).
Running the amp into clipping on inefficient speakers, high average SPLs and/or large rooms is not a fair test.
On the other hand, an amp capable of several hundred watts continuous power may have a rather high noise floor ( among other things). Asking it to sound like a 5 watt amp in a quiet living room on 96dB/watt+ speakers is not fair either. It might be too easy to pick it just by the noise. 🙂 But in its intended use, the noise and class A-B problems might never be heard.
So we can see right away where the ground rules of the test can get tricky.
I think that the amps should be used within their "normal" ranges - whatever that is. So it will be hard to compare amps of widely different power ranges. They should be compared, but it won't be easy to do it.
RANDY B
WELL .....i ve done the exact same thing but in my case i used not something really difficult ....i used something with a nice production and rich ......its short of live recording ...not in a stage but inisde a club yeah yeah i know that most of these recordings are crappy ....well not in this case ...
the sound engineer did a grate job .... so i use the same 3way speakers the same source and the same cd ....( edicted to this system now for more than 3 months now and to the same cd for also 3 months )
the only thing that changes is the amplifiers
results:
since this is a live recording ( with more than 4 voices and 10 instruments ) you can also listen to the public some times in the recording ....
it was more than obvious that this voice ( of the public)while listening to a citacion 12 by nelson pass mosfet version you could listen to this voice from the public ( just one person screaming something ) you could understand that this was inside the club but kind of far away from mikes ....
while listenig the exact same spot with rod elliots p3A the voice was also there but for shure up front ......
performed the same test with 30-40 amplifiers within the 3 months got warious of results and except this small detail many others regarding depth, clearnes of treble, and tightdness of bass ....
then yes many amplifiers sound alike but some of them really have outstanding performance in these amplifiers i will include rods litle thing that impressed me so much.....
i constructed one amp ...dual mono with 2 boards of p3A actually and gave it as birthday present to a friend ..... he said : your amplifier is edictive .....you can stop listenig ......
WELL .....i ve done the exact same thing but in my case i used not something really difficult ....i used something with a nice production and rich ......its short of live recording ...not in a stage but inisde a club yeah yeah i know that most of these recordings are crappy ....well not in this case ...
the sound engineer did a grate job .... so i use the same 3way speakers the same source and the same cd ....( edicted to this system now for more than 3 months now and to the same cd for also 3 months )
the only thing that changes is the amplifiers
results:
since this is a live recording ( with more than 4 voices and 10 instruments ) you can also listen to the public some times in the recording ....
it was more than obvious that this voice ( of the public)while listening to a citacion 12 by nelson pass mosfet version you could listen to this voice from the public ( just one person screaming something ) you could understand that this was inside the club but kind of far away from mikes ....
while listenig the exact same spot with rod elliots p3A the voice was also there but for shure up front ......
performed the same test with 30-40 amplifiers within the 3 months got warious of results and except this small detail many others regarding depth, clearnes of treble, and tightdness of bass ....
then yes many amplifiers sound alike but some of them really have outstanding performance in these amplifiers i will include rods litle thing that impressed me so much.....
i constructed one amp ...dual mono with 2 boards of p3A actually and gave it as birthday present to a friend ..... he said : your amplifier is edictive .....you can stop listenig ......
Andre Visser said:
According to me anyone who enters into an experiment with a desire for a particular outcome is unfit to run it. But then I can not look into the hearts of others and know what's there.
- Status
- Not open for further replies.