Hmmm... sounds a lot like a restaurant preparing a new menu. There are a few purists that won't allow salt at the table for the diners to "tune" for themselves.
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Hi,
What about it.
I greatly respect Charles but on this one my own experiences call it diiferent.
I have found pickups that indeed need the lightest touch (lowest loading) and others that would need 1:1 matching.
Calling one "right" and the other "wrong" is clearly "wrong".
I have found that each pickup has a "right" load.
And adding a transformer has interesting consequences...
Making the Zin lower GOhm range (at frequencies well past the normal audio range) does not produce positive results.
Ciao T
What about it.
I greatly respect Charles but on this one my own experiences call it diiferent.
I have found pickups that indeed need the lightest touch (lowest loading) and others that would need 1:1 matching.
Calling one "right" and the other "wrong" is clearly "wrong".
I have found that each pickup has a "right" load.
And adding a transformer has interesting consequences...
Making the Zin lower GOhm range (at frequencies well past the normal audio range) does not produce positive results.
Ciao T
John, you got most of what I said, but not all.
I don't disagree that some cartridges will have a "sweet spot" with respect to loading. (Talking now only about MC designs.) BUT, what I said was that either those cartridges or their connecting cables have a design defect.
You see, changing the cartridge load does nothing to the sound of the cartridge. It does everything to the sound of the CABLES.
One can easily demonstrate this by using a power amp with an FET input stage (even op-amps!). There the input impedance is solely set by a resistor to an arbitrary value (below around 10 Mohm, typically). If you change the input impedance of the power amp, you will hear the EXACT same type of changes in sound that you hear by changing the "cartridge loading".
Since the input impedance of the phono stage has NO EFFECT on the sound of an MC cartridge, but only on the interconnect cables, tuning that value will give a result for that combination of cartridge and cables that you like in your system.
There is nothing wrong with that at all, if you are a consumer. But if you are a manufacturer and trying to push the envelope by using the best cartridge, cables, speakers, et cetera to assemble a reference system to evaluate your designs, then this is a bad idea. "Loading" the cartridge or cables to get them to sound right simply means that one or the other (or both) are bad designs.
There are MANY, MANY cables that are bright and over-emphasize the leading edge of musical transients. This is impressive, but ultimately unnatural and fatiguing. The same is true with phono cartridges. One can compensate for this by "loading down the cartridge". All that is actually happening is that the cable is being loaded, which tends to roll off the treble and take the edge off of the leading transient.
It is FAR BETTER to use cartridges and cables that don't need band-aids. This true for the end user, as two wrongs don't make a right. It is essential for the designer and the (good!) reviewer.
Ah, I get the impression that you're talking about the built-in audio on your Mac. In that case, I agree that you do not want to evaluate anything using an unaided computer.
Apple does put an impressive amount of engineering and money into their audio systems, but they are by no means up to audiophile standards. What's worse, though, is that PC systems don't nearly measure up to what Apple is doing with built-in audio. In my experience, computer audio is only worthwhile when the computer is driving an external FireWire audio interface (newer USB audio interfaces may be catching up). Once you get into FireWire audio, you're not really listening to your computer any more. That also makes the hardware independent of the "old Mac" versus "new Mac" or even the Mac versus PC question, although FireWire drivers are clearly inferior on PC. In fact, the entire clocking architecture on the PC is flawed. The Mac OS X CoreAudio system is clearly state of the art when combined with the proper external DAC, thus making your old iMac perfectly fine.
My point here is that computer audio is really no easier than vinyl audio or optical disc audio. With vinyl you have needle, cartridge, preamp, and other concerns. With optical disc you have clocking and DAC interface concerns. With computers you have software master clock, data interface, and DAC concerns. Unless you put together a decent system, any playback media choice can easily be disappointing.
P.S. I must admit that I have not read all fifteen thousand postings in this thread, so my apologies if this has largely been covered already.
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How would varying the load resistance affect a cable's performance that drastically when the generator impedance of a typical LOMC cartridge might be anywhere from 1 - 40 ohms? Many HOMC also have rather low source impedances, but by way of disclosure my preference these days runs to low output types like the SPU GM E II, and previously several in the DL-103 family. (103, SA, D, etc.) Noting of course that I have only played with maybe half a dozen or so cartridges in recent times so my experience is very limited. Still I would suspect the generator source impedance would be the dominant factor here. I believe variations in loading have some effect on the both the electrical and mechanical damping of the generator assembly which IMHO is audible to some extent.
My experience (admittedly limited) has been that low impedance LOMC are a little more forgiving of cable quality as long as the shielding is adequate and dcr is low as compared to a conventional MM or higher Z HOMC... (Note that I'm not advocating not using some care in selecting appropriate cables for use with these cartridges.)
I found that the type of resistor makes a diffence too even if they have the same value. That was brought to my attention by Malkolm Hawksford. When they developed the Essex
phonostage with Dr.Bews and Dr.Mills he was able to tell the type of resistor by the character of the noise it made the moment he put the needle in the groove.
phonostage with Dr.Bews and Dr.Mills he was able to tell the type of resistor by the character of the noise it made the moment he put the needle in the groove.
MC cartridge manufacturers state recommendation as for the advised load. As far as I remember, the recommended load is different for different makes and different models.
Well, so much for trying to convey another person's opinion on audio. However, Charles is right, I should have given equal emphasis to cables. Still, I have seen optimum loading change over the years, AND the phono cables remaining the same, so it is the TOTAL effect that is what really counts. This should be well beyond our 'critics' in believablity in any case. Just wait until they insist on YOU taking a double blind test, Charles! '-)
Step 1: They deny the effect.
Step 2: They admit the effect exists but is not important.
Step 3: They say the effect is important and they discovered it.
I have no idea.
Please note that the output impedance of a preamp typically has a similar range as an MC cartridge, so my experiment is relevant.
I have always been suspicious of pulling current from magnetic transducers. I have not tested it but I suspect that pulling current (loading) will get the non-linearity of the magnetic structure altering the signals. Most moving coil cartridges have a magnetic former for the coil. Those that don't will have much lower output, the nature of the beast. The magnetic circuit is in effect in series with the generated voltage and any change in output from loading comes from this series effect (plus the DCR and skin effect of the wire).
I know people like the effect and should be free to load "du jour" but it always sounded closed in and somewhat squashed to me. Moving magnet cartridges are a different story. And then there is Barney Oliver's novel circuit using the moving magnet's internal inductance as part of the feedback eq.
I know people like the effect and should be free to load "du jour" but it always sounded closed in and somewhat squashed to me. Moving magnet cartridges are a different story. And then there is Barney Oliver's novel circuit using the moving magnet's internal inductance as part of the feedback eq.
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For the most part, once the software is sorted the biggest gains come from careful tuning and optimization of the digital interface. Everything from power supply isolation, to clock optimization and mostly noise isolation are the real tricks. We built on top of a very stripped down streamlined Linux distro. There is much more on the web site and all over the web about it.
I agree 100% with the first part of your statement. Concerning the "closed in and somewhat squashed" sound, I agree 100% on the sound quality but my assertion is that the change in sound has nothing to do with the cartridge and everything to do with the cables.
Perhaps for some (many?) solid state designs this is true, but I suspect 100 ohms or more is likely as an expedient against EMI (series resistance), certainly few tube pre-amps will have source impedances of less than a couple of hundred ohms unless they are transformer coupled.
As for the coil cross (magnetic former) in an MC cartridge I'm not certain that there is any magnetic material in the coil assembly at all. The two I have looked at (Benz Ebony H and ZU DL-103) do not appear to have magnetic material in their coil crosses, but it is hard to tell for sure without destroying the cartridge. (They do look like plastic) My SPU is sealed so I am not about to mess with it..
I have generally found that correctly loaded MC cartridges sound a lot better than ones where no attention has been paid to this issue, generally the manufacturer's recommendation works as a good starting point. Transformers however are another issue altogether.. (And I do use transformers)
that formulation of the problem is rather hard to reconcile with "conventional EE knowledge" - as we have discussed here before
resistor noise is fairly well studied, "excess noise" only happens with current flow - "puting the needle in the groove" doesn't cause excess noise significant changes in resistor current in any rational pre amp design I can come up with
was anyone suggesting Carbon Composition??
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Malkolm perceived a change of noise the record produced itself. I can ask him if he also heard a diffence when the neaedle was not in the grove. One problem more that can not be resolved. Anyway, it´s not importand. Use any cheep metal film when that makes the measurement aparatus happy.
Long while back I wrote to Ed Dell proposing making the 75uS pole with a MM cartridge's source inductance and a coupla-K-ohm load R. He replied "lighter loads are better" and didn't publish it. Arf!
Thanks,
Chris
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