Fully agree 😀
But that's actually the way it works (looking from the manufacturer's point of view).
At $995 per pair it would be a poorly performing low-cost-crafted amplifier with low margin and low probability to sell.
At $12,995 per pair - this is a "high-end" - "richly textured, clear, warm, and dynamic" (quoted from the manufacturer's web site) with premium margin and much higher probability to sell 😉
Back to the point of FR "cheating" - I can imagine such thing in automotive and/or any budgetary level equipment that could have:
- Simple tone control circuits, sometimes not easy to zero-out (don't expect any precision);
- No tone controls bypass possibility;
- "Loudness" circuit always on.
In serious gear, it's not that easy (and in most cases no need) to cheat.
Anyway, I don't understand why the OP does not want to name the manufacturer / model of the amplifier. I agree with a number of previous posters, quality of the curve in the 1-st post looks suspicious - especially some random drops in magnitude (resonances? caused by what?).
How young do you think we all are? We all remember that era, but with no evidence or specific model numbers its hard to believe you. There must be at least something we can x-ref to some modern measurements or someone has on the shelf somewhere, otherwise we are arguing about bargain basement stuff that is all landfill now. Pretty sure there are some rotel-820 meaurements on here and someone must still have a NAD3020 as a couple of data points in the 'my first not carp stereo'?
Yet many manage with no problem and you can get USB adaptors for the comms now.
Odd, as this seems to indicate you were a repair tech of some type. Unreliable gear is a good source of income and usually loved by those who make their money from fixing it. Wrong calling perhaps, or did you just fix things as favours in which case I can totally understand your sentiments. But remember we made good stuff in the 60s.
This is not serious. Nearly al true hifi equipment from the seventies and after that
has a flat frequency response sometimes with some rolloff at the band ends.
Only few have an integral loudness function which can be switched off in most
cases.
Especially in early german gear (and in some Yamaha items) you can find adjustable
loudness which I consider to be a useful feature.
Among hundreds of different products of manufacturers from various continents that
I had in my workshop not one had a flawed response by intention.
So I think you both are in the position to prove your claims.
OP quote: "some tone controls are activated only by a speaker load" - please tell us
which particular german and british brands you talk about (post 26).
This kind of measurement is typical of single ended tube amps. The high output impedance makes them highly sensitive to the loudspeaker load.
$13000 is a piddle. Try these $350.000 monoblocks. 150W SE tube monoblocks...
An externally hosted image should be here but it was not working when we last tested it.
Wavac SH-833 monoblock power amplifier | Stereophile.com
However this $350 grand gets you 550lbs of amps...
An externally hosted image should be here but it was not working when we last tested it.
Johan-Kr
To understand this weird (to say it politely) post, we must add:
amplificateurslegrand.ca
where a "6BL7, 1.5 Watts at 2 Vrms input, our best amplifier for low sensitivity speakers" homemade (DIY 😉 , get it?) amplifier is being offered for sale, driven by an also DIY/homemade preamp :
" Preamplifier, the best no feedback preamplifier ever built, sold for price of parts only"
an we start to understand this indiscriminate attack against *all* commercially made Audio Equipment, based on a poor and misunderstood measurement, on misused equipment (attenuating signal under test down to -90dB screams of that) , to boot based on an statistically meaningless sample of 1 (one) .
Certainly if "they" sell and "I" do not, there must be some cheat or conspiracy, pure Logic .
Oh my God.
+
amplificateurslegrand.ca
where a "6BL7, 1.5 Watts at 2 Vrms input, our best amplifier for low sensitivity speakers" homemade (DIY 😉 , get it?) amplifier is being offered for sale, driven by an also DIY/homemade preamp :
" Preamplifier, the best no feedback preamplifier ever built, sold for price of parts only"
an we start to understand this indiscriminate attack against *all* commercially made Audio Equipment, based on a poor and misunderstood measurement, on misused equipment (attenuating signal under test down to -90dB screams of that) , to boot based on an statistically meaningless sample of 1 (one) .
Certainly if "they" sell and "I" do not, there must be some cheat or conspiracy, pure Logic .
Oh my God.
But he knows his measurement stuff (post 26)
(post 1) while the curve shows a frequency range from 3 to nearly 100 000 Hz...
Please note that this thread is about the majority of hifi gear available on the market presumably intended to cheat customers.
The thread is not about some crazy single ended amps with questionable output resistance. I admit that this is an area where
aberrations in response can happen.
Billshurv brought up the first one, dissing anothe SE amp.
And I agree - SE tube amps doesn't really fit into the discussion envelope...
Johan-Kr
I did introduce an SE frequency response only because they generally have the worst FR deviations into real loads and are still less than the OP showed for his nameless SS amp.
However the Wavacs are in the right ball park. 5dB up at the low end and 5 down in the midrange. what did mad Mikey Fremer make of them?
My yes, that describes a tone control perfectly. But it re-inforces the point that you generally have to pay big bucks for something THAT bad. I still don't buy the OP post unless he had the loudness button pressed in.
However the Wavacs are in the right ball park. 5dB up at the low end and 5 down in the midrange. what did mad Mikey Fremer make of them?
My yes, that describes a tone control perfectly. But it re-inforces the point that you generally have to pay big bucks for something THAT bad. I still don't buy the OP post unless he had the loudness button pressed in.
Huh, I am not going to borrow each junk amp from the 80s in the used store to show you a bunch of -90 db graph , no way.
If you are knowledgeable you will know that it works both with speakers impedance tricks and tone controls that activate on a speaker load.
The Quantum asylum is a not too expensive but extremely precise gear which only tolerate a 2vpp signal input and clips easily. for the FOURTH time I used voltage divider resistors and did a control test, I used 2 types of speakers with approximately the same results.
The amp cost 1000$ in 1981 and is made in Germany. Owned it from new.
At least FOUR people posted here to back up what I said.
What I am saying is a positive for diyers who aim to be honest and not to marketing sales. We also just need to be realistic about our self made amps in terms of "details" and bass extension compare to many commercial gears which are cheating the frequency curve. A simple cap and resistors can boost the bass anywhere in a transistor circuit, so it is not that obvious, some activate when sensing louder bass signals, nowadays they have sound shaping processors. DIY stuff is honest.
If you are knowledgeable you will know that it works both with speakers impedance tricks and tone controls that activate on a speaker load.
The Quantum asylum is a not too expensive but extremely precise gear which only tolerate a 2vpp signal input and clips easily. for the FOURTH time I used voltage divider resistors and did a control test, I used 2 types of speakers with approximately the same results.
The amp cost 1000$ in 1981 and is made in Germany. Owned it from new.
At least FOUR people posted here to back up what I said.
What I am saying is a positive for diyers who aim to be honest and not to marketing sales. We also just need to be realistic about our self made amps in terms of "details" and bass extension compare to many commercial gears which are cheating the frequency curve. A simple cap and resistors can boost the bass anywhere in a transistor circuit, so it is not that obvious, some activate when sensing louder bass signals, nowadays they have sound shaping processors. DIY stuff is honest.
According to my guide to internet trolling this is one of the standard defences when asked to back up some BS. Just ONE popular named amplifier will help.
Tone controls that measure speaker load and turn on? Pray tell more. If you mean that low damping factor gives you FR deviations why not just say so.
A fool with a tool is still a fool. Onus is on you to prove your test methodology is not at fault.
As SY likes to say, the plural of anecdote is not data!
Here you go again with a 70/80s amp that has intelligent bass boost. Come on, examples. Careful saying DIY is honest or people will ask you to defend every quote on your website!
I am out here. This case is hopeless.
Have to admit that I did not inform myself about earlier threads of this gentleman, see for instance http://www.diyaudio.com/forums/digital-source/273021-sound-card-conspiracy.html .
This thread here shows that an undiscovered conspiracy is going on to convince the OP that there is a conspiracy for nonlinear responses in commercial gear.
Have to admit that I did not inform myself about earlier threads of this gentleman, see for instance http://www.diyaudio.com/forums/digital-source/273021-sound-card-conspiracy.html .
This thread here shows that an undiscovered conspiracy is going on to convince the OP that there is a conspiracy for nonlinear responses in commercial gear.
I don't know you but you keep making personal attacks.
I truly believe there is much bs in the world: expensive amp cases, people are deaf, girls put makeup, people lie.
I found many conspiracy in many commercial gears: planned obsolescence
So yes the sound card sound better with less opamps and yes Manufacturers cheat the frequency response of their amps to SELL, are you someone from another planet??
I truly believe there is much bs in the world: expensive amp cases, people are deaf, girls put makeup, people lie.
I found many conspiracy in many commercial gears: planned obsolescence
So yes the sound card sound better with less opamps and yes Manufacturers cheat the frequency response of their amps to SELL, are you someone from another planet??
Somebody deleted his post with a PS Audio test report that confirmed a bass lift in the measurements.
Thank you for the example which I consider to be an exception.
PS Audio Sprout integrated amplifier Measurements | Stereophile.com
Please, gabdx, at least tell me which german amp of 1981 that you own from new (your post 50) shows
the abnormal (normal in the sense of common for you) response.
I or one of my friends may be responsible for that one. I promise to buy it back for the full price if your assertion is true.
Thank you for the example which I consider to be an exception.
PS Audio Sprout integrated amplifier Measurements | Stereophile.com
Please, gabdx, at least tell me which german amp of 1981 that you own from new (your post 50) shows
the abnormal (normal in the sense of common for you) response.
I or one of my friends may be responsible for that one. I promise to buy it back for the full price if your assertion is true.
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It has been pointed to you already that what you describe is most probably the result of highish amplifier output impedance (Ro).
Please do try to make a measurement of Ro versus frequency on this amplifier (at the same power level that you did the published frequency plot).
It will add to your knowledge and will help transform the noise you introduced here to some -already well known- facts.
George
gabdx - dropping the SE tube amp silliness, I have a couple of questions.
You stated that you measured at an output of around 10 watts.
I presume the amplifier was running into a dummy load, and you measured the voltages across this load.
What was the nature of this load - was it a simulated speaker, a real speaker or a 8 ohm power resistor? Or did you use a higher resistance value?
How high was the volume control? Some amps has no defeat on the loudness function, and a low level on the volume control will apply some loudness.
Johan-Kr
You stated that you measured at an output of around 10 watts.
I presume the amplifier was running into a dummy load, and you measured the voltages across this load.
What was the nature of this load - was it a simulated speaker, a real speaker or a 8 ohm power resistor? Or did you use a higher resistance value?
How high was the volume control? Some amps has no defeat on the loudness function, and a low level on the volume control will apply some loudness.
Johan-Kr
It's called 'voicing'. That's what you get if you tune for sound that the designer/reviewer likes.
It's also a reason why some amps and speaker combinations sound 'better' than others - it can be overdone.
Nothing wrong with it, as long as it helps sell the equipment.
Jan
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