Not that rare. I have one and it was in the recent catalog. The case for the 1/4" capsule has a space for it. The 1/8" stuff is a bigger pain to find. I had one but the capsule was contaminated and did not work any more B&K offered me a $100 discount on a new one (after charging me more than that to tell me it was bad).
On the mike preamp I would be more concerned about leakage in the 300 pF coupling cap. It would take very little there to cause serious noise issues. My big concern on carbon comp resistors at very high values is the moisture sensitivity. The surface contamination could dominate the measured value and change with the weather.
Like for cars batteries ? We have the - to the ground, un Europa. I don't know if any difference with corrosion.
Those files weren't supposed to be there to help people to figure out the sampling-rate effects ? And they are biased ?
There's plenty of commentary out there about the fact that a lot of the hi-res vs. CD comparison material is bollocks, because the supposed better material in fact has been doctored to sound better. Probably the marketing executives went into meltdown when they couldn't hear a difference, so they issued a directive, make sure consumers get the right message ...
Frank
For a charge based transducer at low frequencies the current noise at the input of the pre-amp is what matters. Equivalent current noise of a resistor is sqrt(4KT/R), Nyquist 1928. The noise goes down as the sqrt() of the resistance. Or as B&K quoted in 1972 from Cobbold...
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V3 bootstrapping the drain of the input FET does that, bootstrapping the resistors lowers the input time constant, folks often think this lowers the noise but it does not.
I could not read your scan till I took it off line.
Did you notice John's schematic had a pin designated "heater"? I guess they figured out that without the filament of a V14 they would have to do something else.
JC, which B&K instrument is this ?
Is this a 2010? If so, what settings? It's obviously not the 1/3 8ve filter set
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Where did you get your 100G resistors in 1974? This would have been of considerable interest to me around that time.
What physical size roughly ?
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Err.rrh! What IS your point?
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Does that mean there is no musical content above 40kHz? Even with DXD & DSD?
From Jurassic attempts to find vinyl with high slew rates and also some mike trials, the only musical signals above 20kHz would be cymbal crashes recorded close up.
Anyone know different and can show examples? IMHO, musical content needs to exhibit the characteristics of music. eg dynamic range; remember loud bits and soft bits ... unlike modern 21st century noise.
PMA, do you know if the vintage Telarc stuff issued shows dynamic range above 20kHz? From what I know about their mikes, it is possible.
Scott, excuse me if I exclude some of your exotic instruments from foreign lands.
... but if you can send a beach bum a recording or two, he might be persuaded that these are music. ________________________
Frank I think you were asking about detailed microphone distortion measurements over a large frequency range. I can say these are quite hard to do from experience circa 1980. The only published stuff I've seen is several Sennheiser AES papers where they show the THD advantage of their symmetrical RF mikes.
However, the 'conventional' evil examples in their paper are not really representative and it is trivial to have better performance. Their mikes are excellent but in fact suffer early overload for other reasons which might be more important to a recording engineer.
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Who cares?? SE tubes distort like a hell, and they are considered great sounding by many. Not me, thanks.
Glass resistors up to and maybe over 10^12 Ohms were readily available. They would have easily fit in a mic body.
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Agree. Particularly to the extent that a triode follows the ideal Langmuir-Child characteristic, a very-lightly-loaded common-cathode- or common-anode-connected one has extraordinarily low distortion. Of course most triodes are not ideal, but many are very good within the middle range of biasing.
However PMA probably did mean SET power amps with significant plate loading.
kgrlee,
I am not so convinced that there truly isn't any information above the 20Khz range as much as the present multi-microphone recording chain just can't get the phase response correct so that we can reproduce this information in any coherent way. If the phase response and timing was correct then we could talk about it, but that is the problem with most of what we are always talking about in upper frequency reproduction. I in-order to reproduce the sheen of a cymbal or overtones from other instruments we would have to get that correct or it is just smeared in the reproduction and then we just hear it as noise. Just my opinion of what is going on in the reproduction and recording chain.
I am not so convinced that there truly isn't any information above the 20Khz range as much as the present multi-microphone recording chain just can't get the phase response correct so that we can reproduce this information in any coherent way. If the phase response and timing was correct then we could talk about it, but that is the problem with most of what we are always talking about in upper frequency reproduction. I in-order to reproduce the sheen of a cymbal or overtones from other instruments we would have to get that correct or it is just smeared in the reproduction and then we just hear it as noise. Just my opinion of what is going on in the reproduction and recording chain.
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