Thanks George, for the links. They are VERY INFORMATIVE.
I'll stick to Moving Coils, thanks.
Of course we cannot leave out Moving Magnet or Moving Iron cartridges from consideration. Certainly, less committed vinyl players are going to use them, and sometimes, collectors use them a well, because of the number of stylus configurations available, for one reason.
That is why the Parasound JC-3 is dual function, i.e. both MM and MC friendly.
The new Constellation Perseus phono playback system is also both MM and MC compatible, as well as the JC-80 preamp was, as well.
As SY denotes, the VENDETTA RESEARCH SCP-2 phono stage has VERY HIGH input capacitance, due to the use of both P channel and paralleling a number of ultra low noise (large area) jfets. This makes the Vendetta unsuitable for MM cartridges or even hi output MC cartridges. It was designed for a certain range of MC cartridges, only.
About 20 years ago, Richard Marsh first commented that the rather high input capacitance of the Vendetta did not allow it to achieve 47K input impedance (if that were at all necessary) even with a 47K input resistor.
No, the Vendetta was designed for optimum operation with source resistances of 2 to 50 ohms or so, no more. This is the tradeoff between extremely low noise, complementary push-pull operation (for low noise without feedback) and high input capacitance.
P channel jfets have lots of input capacitance due to their extremely large area in order to keep the noise low.
Serious designs that DEMAND low capacitance input are generally made exclusively with Njfet devices at the input. This usually increases the ultimate open loop distortion, and this is the main tradeoff.
I'll stick to Moving Coils, thanks.
Of course we cannot leave out Moving Magnet or Moving Iron cartridges from consideration. Certainly, less committed vinyl players are going to use them, and sometimes, collectors use them a well, because of the number of stylus configurations available, for one reason.
That is why the Parasound JC-3 is dual function, i.e. both MM and MC friendly.
The new Constellation Perseus phono playback system is also both MM and MC compatible, as well as the JC-80 preamp was, as well.
As SY denotes, the VENDETTA RESEARCH SCP-2 phono stage has VERY HIGH input capacitance, due to the use of both P channel and paralleling a number of ultra low noise (large area) jfets. This makes the Vendetta unsuitable for MM cartridges or even hi output MC cartridges. It was designed for a certain range of MC cartridges, only.
About 20 years ago, Richard Marsh first commented that the rather high input capacitance of the Vendetta did not allow it to achieve 47K input impedance (if that were at all necessary) even with a 47K input resistor.
No, the Vendetta was designed for optimum operation with source resistances of 2 to 50 ohms or so, no more. This is the tradeoff between extremely low noise, complementary push-pull operation (for low noise without feedback) and high input capacitance.
P channel jfets have lots of input capacitance due to their extremely large area in order to keep the noise low.
Serious designs that DEMAND low capacitance input are generally made exclusively with Njfet devices at the input. This usually increases the ultimate open loop distortion, and this is the main tradeoff.
PS - I'm glad you got both Dick and Erik to contribute, now we need to work on Barrie.
Barrie sort of vaguely committed to an article without specifying a timeframe or subject (though I would accept any subject he'd fancy).
I keep sending him sample copies.
Maybe I should try to tickle him again.
Another I'd like to add is Dennis Feucht, and although we have been in contact, no joy so far.
I've got a Ron Quan article lined up for Vol 6 BTW. Basics of noise.
jan
Scott, Hans did some explanation in the side bar at the end of the article specifically for figs 4 & 5. That is not what you are looking for?
jan
I'll have to work harder on that commitment thing. How much do I have to spend before you don't sneer?
edit: I notice that there's no input capacitance spec for the JC-3. And somehow, Stereophile missed measuring it.
I've never seen JA measure capacitances. Did I miss something? And as mentioned before, JA doesn't seem to know about current noise --- he states that short-circuiting the input and putting gain at maximum is a worst-case condition for measuring noise.
But at least he does measure things, unlike most other similar publications.
No, apparently he did. This is a critical spec, at least for those with commitment.
There is a 100pf cap at the input to ground for the JC-3. Some criticism has made me now wonder if 50 pf might be better?
No SY, you are not as 'committed' as most of my customers, nor do I expect you to be so. I do wish you would get off my back for what I do for my 'committed' customers, however.
No SY, you are not as 'committed' as most of my customers, nor do I expect you to be so. I do wish you would get off my back for what I do for my 'committed' customers, however.
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But that's not the only source of input capacitance. Should I infer that you've never actually been committed enough to measure it?
When your customers start designing and building their own phono stages, then writing articles showing people how they're engineered, that's commitment. Of course, then they're no longer your customers.
Quote:
Yes, the "man in the street's" prevalent notion of what 1.5W of coherent optical power would amount to is certain to be a gross underestimate.
The Darvin award is meant for those who remove themselves
from the gene pool.
3 weeks ago I witnessed helicopters hoovering over our neighborhood,
and read in the paper next day that they were searching someone
who was blinding airliner pilots approaching Stuttgart airport with
a green laser pointer. Not for the first time.
Gerhard
Yes, the "man in the street's" prevalent notion of what 1.5W of coherent optical power would amount to is certain to be a gross underestimate.
The Darvin award is meant for those who remove themselves
from the gene pool.
3 weeks ago I witnessed helicopters hoovering over our neighborhood,
and read in the paper next day that they were searching someone
who was blinding airliner pilots approaching Stuttgart airport with
a green laser pointer. Not for the first time.
Gerhard
Designing and writing articles is one thing.
Listening closely to the impact of reproduced music is a different thing.
There is no necessary connection between the two, not with all people.
Probably those who don't listen closely to the impact of reproduced music wouldn't have a clue what I'm talking about. Thus, possibly, some designers don't aim at realistic impact of the reproduction of music. Hence, the result of their design may not satisfy those who listen closely to the impact of reproduced music.
Then why did you accuse him of such a thing? As far as I'm aware, you haven't spent any actual time with him. I think you're being terribly unfair and you owe him an apology.
You are welcome Mr.Curl.
When I find something that I consider useful, I communicate it.
No one is asking you to dismiss moving coils.
They are demanding mistresses. We sympathize
I follow this thread long enough to understand that SY has his way to tickle you to a direction that you yourself would explore, one way or another (he is your good demon so to speak).
You rock and you sneer but you would experience a void if you wouldn’t feel him on your back.
SY how much do you weight?
George
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