Another picture that I scanned in and posted years ago with an LT1028 vs AD745, fairly dramatic HF noise peak on the bipolar.
I don't think anyone was suggesting I steer Stereophile's content primarily toward the interest of advertisers, John. And I am sure many advertisers wish I didn't publish measurements at all
But perhaps it is appropriate to quote my late mentor John Crabbe on the three-sided balancing act that affects review magazines: "If you tell the truth about components you review, there will always be a small percentage of companies at any one time who are not advertising in your pages. But if you publish the truth, you will have a good magazine. And if you have a good magazine, you will have readers. And as long as you have readers, disgruntled advertisers will eventually return. But if you don't tell the truth, you won't have a good magazine. And if you don't have a good magazine, you won't have readers, at least not for long. And if you don't have readers, you won't have advertisers." (See Communities | Stereophile.com)
John Atkinson
Editor, Stereophile
Peak like resonance of cartridge inductance with cable capacitance, or something else?
John,
He is sadly missed. I always enjoyed reading his work.
With the passing of his Generation HiFi Mags in the just are not what they used to be, in fact most are, if not dead, then at least at the "start to smell funny" point.
Most well met and well said.
If I may be so bold, you have done a great job keeping Stereophile in the Balance. And it is good to see new people on board, as well as new topics like with Audiostream.
I would also add that Stereophile's strong internet presence (compared to many UK Mags) has helped tremendously.
I doff my hat.
Ciao T
He is sadly missed. I always enjoyed reading his work.
With the passing of his Generation HiFi Mags in the just are not what they used to be, in fact most are, if not dead, then at least at the "start to smell funny" point.
Most well met and well said.
If I may be so bold, you have done a great job keeping Stereophile in the Balance. And it is good to see new people on board, as well as new topics like with Audiostream.
I would also add that Stereophile's strong internet presence (compared to many UK Mags) has helped tremendously.
I doff my hat.
Ciao T
Hi John,
Your measurement-based reviews are the single biggest reason I read Stereophile. One thing I really like is the fact that you incorporate a standard loudspeaker load emulation into your frequency response tests for amplifiers. It is tremendously helpful to get an idea of what kind of coloration mught result from a given amplifier's output impedance (as opposed to the benign resistive load).
The same could be said for the loudspeaker test load emulator you use - it can't possibly represent the vast array of different loudspeakers out there, and yet it is tremendously useful. I'd argue that you should concoct a "standard" MM cartridge input load and use it in measurements of the cartridge noise in addition to the shorted input. As a reasonable "typical" cartridge source load, I'd suggest something like the Shure V15, as its inductance is right in the range of many MMs. I would not use something like the Grado, as it would give results that might be a bit optimistic for the average user.
I'd be happy to design and build such a cartridge load for you. It is not a difficult task. Indeed, one could actually take an old V15 and put it in a small metal box with connectors and maybe add 100 pF in shunt to account for typical turntable wiring capacitance (or let it be in the interconnect you use to connect it to the preamp under test).
BTW, I would LOVE to see every amp/cable/loudspeaker combination reviewed have its frequency response as seen at the terminals of the loudspeaker measured before or after the listening review, without the reviewers knowledge of the results if done before the review.
Cheers,
Bob
Actually some people who write here frequently do suggest it (to my view, erroneously). As an example you can see a cynical comment on the previous page.
I remember sitting in the office of a friend who was an editor at la Nouvelle Revue du Son in Paris. He as asking me what I thought of the magazine. I said "It a nice magazine, but in the reviews you guys like everything. How can I judge?" He rolled his eyes and said "I know, I know, I hear it all the time. But we're in a tough spot. We want to please the readers, but we also need ads and equipment to review. If we are too harsh then no one wants to send us equipment or buy ads. It's not an easy balance."
I still find it very hard to judge reviews in audio mags - in print or online.
Many years back there was an IEEE conference with two co-chairs. The first one's biography was a page long and listed bunches of technical awards, accomplishments and positions held. The other chair's bio was very short. He had won the Lenin and Nobel prizes.
Magazines do loose advertising from unhappy folks. But in one example I know of first hand the editor/publisher sent me a copy of the advertiser's letter. The advise to me was ignore the advertiser, the lost revenue would be noticed, but the content was more important.
Now T & JC while giving out secrets, I should continue my power supply tests with some low noise diodes. Any suggestions?
Peter Moncrief said that the role of the reviewer is to help the reader
differentiate between products. There is no such thing as a "best"
amplifier, only ones which best fit a particular customer's needs.
Hi,
I think I can do wout the Lenin one, or the Order of Karl Marx at that (the east german equivalent). I wouldn't mind a Nobel.
As I get older I find what I give out as Bio/CV gets shorter as I get older. Very little is really worth mentioning.
I personally use pretty generic schottkies, like 21DQ100 or such, depending on power levels.
But I also design significant DCR into the custom transformers for my gear (precise details are not up in public, you can PM me) and have the wound fully symmetrical and electrostatic screens, so noise on the primary does not pass easily to secondary.
Using generic transformers I try using cancellation of leakage (works well with mummified doughtnuts) and add external resistor to get the DCR up enough.
I also tend to follow the actual rectifiers with a "small and low inductance" capacitor in a small loop before things go into the main reservoir cap's, usually with judicious slices of Ohms designed into the PCB or very thin wires to damp any unwanted tank circuits.
To be honest, designing PSU's into PCB's or normal 3d Space is a bit of an art, it helps to be able to really visualise the different elements. The difference can be many dB for what may seem trivial changes...
Ciao T
I think I can do wout the Lenin one, or the Order of Karl Marx at that (the east german equivalent). I wouldn't mind a Nobel.
As I get older I find what I give out as Bio/CV gets shorter as I get older. Very little is really worth mentioning.
I personally use pretty generic schottkies, like 21DQ100 or such, depending on power levels.
But I also design significant DCR into the custom transformers for my gear (precise details are not up in public, you can PM me) and have the wound fully symmetrical and electrostatic screens, so noise on the primary does not pass easily to secondary.
Using generic transformers I try using cancellation of leakage (works well with mummified doughtnuts) and add external resistor to get the DCR up enough.
I also tend to follow the actual rectifiers with a "small and low inductance" capacitor in a small loop before things go into the main reservoir cap's, usually with judicious slices of Ohms designed into the PCB or very thin wires to damp any unwanted tank circuits.
To be honest, designing PSU's into PCB's or normal 3d Space is a bit of an art, it helps to be able to really visualise the different elements. The difference can be many dB for what may seem trivial changes...
Ciao T
Reading between the lines becomes very important in many reviews....and sometimes even read in between the lines of John's comments
Are you expecting one any time soon?
Hi,
I rather doubt it.
Audio is not a field that win's you Nobel's and I sure hope I never qualify for one in politics or the likes...
I merely said I would not mind being given one.
Ciao T
I rather doubt it.
Audio is not a field that win's you Nobel's and I sure hope I never qualify for one in politics or the likes...
I merely said I would not mind being given one.
Ciao T
Not sure what you mean. There was no sarcasm intended. Everything I said was intended to be positive and constructive. Are you referring to my use of the term "benign resistive loads?" Everybody agrees that they are relatively benign loads for amplifiers, including John.
Cheers,
Bob
Yes, dummy loads may be much more revealing.
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I agree that it is a good idea to test amplifiers on real loads, but what is the point in frequency response curve of an amplifier loaded on some complex load? What would you get loading any "standard" signal generator on such a load? How useful will be the curve? And, finally, what is "Standard speaker"? Which one? Even if you limit choice of speakers by a single dynamic full-range cone speaker, which one is "standard"?
In my mind, it is much better to tell the man that he is wrong, instead of making fun behind his back.
Yes, if you want to see distortions of 2W SE amp loaded on horn speaker, or 100W P-P amp loaded on some 3-way speaker with complex crossovers that have dips in impedance that engage overload protection. But what's the point of frequency response curve output vs input of an amp loaded on some complex load?
Anatoliy, you might be surprised. No need of testing 2W SE tube amps only or overload protection function. Try it and you might be surprised.
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