It's amazing what can be done with an effects box if the original recording engineer didn't quite do it for you. But an EQ setting that's good for Ella Fitzgerald may sound terrible for The Beatles.
I don't know, but I do not think that I was being fooled in any way. It is certainly an eccentric design, very heavy, BUT what I heard from this company, and I was just walking down the hall at CES listening to different exhibits when I came on it. I have NO idea why it sounded as good as it did. It was a vinyl recording, it was an expensive amplifier/preamp combination. I am pretty sure that they were using a Tannoy horn loaded system or two. Whatever they did, I sounded great, and I had NO IDEA of any measure of it, before listening to it. However, it probably played at no louder than 100mW of power, being entirely horn loaded, from my previous K-horn experience.
It just goes to show that you cannot always predict performance. I suspect that the horn throat distortion might have been cancelled by the amp's distortion, and the total result could potentially be very linear. Think it through, everyone.
It just goes to show that you cannot always predict performance. I suspect that the horn throat distortion might have been cancelled by the amp's distortion, and the total result could potentially be very linear. Think it through, everyone.
IMO one thing is for sure. Plunking down 350 dimes and having the guy come halfway around the world to set up your stereo is the antithesis of diy audio.
In all frankness, whenever I look at a Stereophile I only read the measurement sidebars and the larger percentage of equipment measures very well. I don't care much what someone I don't know thinks about how a piece of equipment sounds. Having said that, I know people who spend tons of money on equipment on the word of those folks and others, and they have really nice systems that sound really good, much better than anything I've ever put together.
John
Once again: NO IQ SETTINGS. It is misunderstanding based on graphs from the article. Graphs are results of load of the amp on so called "Dummy Load" that mimics complex loudspeaker impedance. If you connect such a load to one of amps designed by John Curl you will see FLAT frequency response. Not because of no IQ, but because John's amps have extremely low output resistance.
This particular amp has relatively high output resistance, that's why output voltage depends on load impedance.
As SY wrote, dentists may not know Ohm's law. But DO YOU KNOW OHM's LAW?
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You seem to be saying that an amplifier's output impedance is of no interest to anyone because when it feeds a resistive load it gives a flattish response. I'm saying that I'm not convinced of anything from its frequency response into a resistor because I'm going to use it to drive a complex speaker impedance. If the person measuring the amp can state from his measurements that the output impedance approximates to a resistor of so many Ohms then I can hazard a guess as to how wiggly the response will be coming from my speaker. But presenting me with a flattish graph from feeding a single resistive load won't tell me anything about how poor the amplifier will sound from my speaker.
People seem to be saying that the amp is obviously like an ideal source driving a resistor, but if that is so, why are we measuring it at all? The same people say that imperfections at -120dB make their ears bleed when listening to a SACD, but seem prepared to accept huge deviations from a $350,000 amplifier without question. Surely the measured 10% distortion and 10dB bass boost when driving a real speaker might give a clue as to how the amp happens to make the anodyne sound of Ella Fitzgerald sound a bit different (better even?) compared to one of those cheapo $5,000 jobs with the 0.0001% distortion and flat frequency response from 1-100,000Hz.
The amazing thing is that anyone believes there to be a secret formula within the few variables that can be tweaked in a simple, antiquated circuit that somehow generates an alchemical transformation of any waveform fed into it, beyond measurement and duplication using a sub-550lb effects box. And that the builders of the amp (a bunch of electronics technicians, vinyl enthusiasts and marketing people) have secret powers that defy all analysis and economic sense.
Could a parallel to an amplifier's output impedance be that of a car's weight and wind resistance?
If we want to test a car's acceleration and top speed in isolation we can do it on a rolling road, with our resistive dummy load being a constant force opposing the vehicle - no need to bother with that confusing air and inertia. In such a test, a huge heavy car with terrible aerodynamics would outperform a Ferrari.
If we want to test a car's acceleration and top speed in isolation we can do it on a rolling road, with our resistive dummy load being a constant force opposing the vehicle - no need to bother with that confusing air and inertia. In such a test, a huge heavy car with terrible aerodynamics would outperform a Ferrari.
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Look, just buy a pair of JC-1's and save yourself $340,000! ;-) MY output impedance is VERY LOW.
I build, not buy, but if I were to buy, a pair of JC-1s would be infinitely preferable. But really, John, you have to figure out how to get 10% distortion and that huge spray of high order harmonics before you can have high end cred. Otherwise, it will be just tin ears like me who think your stuff is good. 😀
Just removed another derogatory post. Guilty party now has an infraction. No matter how much you disagree with the poster/content of that post the response must meet forum guidelines.Seriously? That a big stretch. More likely a recording tracked and mixed on horns driven by an old tube amp. Thus manipulated to sound best on that kind of system.
Actually, I checked it out. It is quite possible that the Wavac's distortion, especially lower order, would track typical horn or even a direct radiator loudspeaker.
Just a question about large distortion figures. Presumably distortion means that something is being added or taken away from the desired signal; clipping suggesting that something is being taken away, for example. At huge figures such as 10%, does this not constitute an actual dynamic compression of the signal, as well as harmonic distortion? The amplifier's gain can be regarded as having gone down at high volumes, so the talk of wonderful transient response from primitive circuits seems a bit like wishful thinking..?
Do we mean the signal across the speaker terminals, or the acoustic output of the speaker measured with a microphone?
@Wavebourn
If this idea were possible, wouldn't that have a bearing on your idea of testing the amplifier with only a resistive load? You might get a flat frequency response, but the amplifier's effectively pre-distorted signal would not be linearised by the load, so appearing much worse than it actually would be in use.
It might look a bit odd to have to stipulate a different load for each test!
It depends on whether it is odd or even order. Odd order compresses (or, rarely, expands) dynamic range because it generates some 'distortion' at the original signal frequency. Even order does not, it just adds extra stuff.CopperTop said:
Going back to output impedance, we are not interested in the output impedance of an amp if it is sufficiently small. If it is not small (e.g. at frequency extremes, or due to incompetent/idiosyncratic design) then it ought to be measured and presented in the review alongside the frequency response.
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