Well even JFET's start to fail on Ib with 100G resistors and doubling every 8 C, this is just engineering. John time to stop I know this punctures one of your strongly held fantasies, this has been hashed over before lets move back OT. In any case this is such a tiny issue issue considering A weighting and at the low end LP's are so bad how could it matter?
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Unfortunately, it does matter. The cop out by many in the electronics crowd, when replay is not up to scratch, is that our glorious circuits are not to blame, it's those terrible microphones and speakers which are the trouble makers, how can you get realistic playback when those fellows are mucking up everyone's chances. Well, I would like to see real figures about good these items are, in real situations, and not on a testbench pedestal ...
Frank
To linearize the response curve at low frequency ? Or because the impedance of their cartridges is low enough at 10Hz ?
Humidity is possible when a measurement mike is used outdoors in the rain. These mikes even had a heater, but moisture contamination was certainly possible. I thought that they were being a bit conservative, but that is exactly what they told me, back almost 40 years ago. In 1974, John Meyer and I went to Copenhagen to B&K and ordered 24 2619 microphone preamps with 1G resistors. They charged us extra, and later, they upgraded all their mikes when they found that it worked pretty well. You can ask John Meyer, himself, if you don't believe me. Go ahead! You know the president of MEYERSOUND.
I upgraded all the GD mikes, myself, in 1973, but it was easier, because they used Nagra instrumentation mike preamps, and they were more accessible to modification.
I upgraded all the GD mikes, myself, in 1973, but it was easier, because they used Nagra instrumentation mike preamps, and they were more accessible to modification.
Again B&K Technical Review No. 3 1972 a great survey article on microphone noise. Companies release products and are very resistant to change them, the marketeers were happy at the time, who knows, but the engineers were totally on top of all the issues. John it's pretty clear you have no intention of giving ground to anyone else's opinion or alternate views so these discussions are unfortunately a waste of time.
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Look everyone, I showed today the ORIGINAL schematic for the B&K microphone preamp. It had the equivalent of 100 meg input resistance. The reason given to me by a B&K engineer at my office in San Francisco in 1973, was that they kept the resistor values low because of potential humidity problems. I found that a higher value made it usefully quieter, with 4133 capsules, so I modified all the mikes that we bought for the GD to higher values. However, the B&K preamps were more complex and difficult to modify, so we went to them for the upgrade. This is when they ultimately raised their input Z to 1966 standards as shown by Mead Killion in the AES preprint. I don't claim to have invented the upgrade, Mead did it in 1966, and gave me the idea. However, we HAD to pay extra for the upgrade in 1974. It is of course difficult to tell a real microphone expert how to improve their microphones, but we had to, in order to get it done. Perhaps research did not talk to production. That happens, and it even happened at Ampex when it came to record and reproduce heads. They were WAY behind when I came on the scene, in the audio department. Within 5 years they had used every improvement that I suggested in 1968, in their production machines, but not without a fight. I didn't INVENT 1 or 2 mil lams, I just insisted that they be used. Sometimes you just have to embarrass people in order for them to improve the product.
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1) why in THIS thread?
2) I am neither claiming I am the best nor I am saying my designs are the best. If I did, I would have to prove it.
I don't doubt this, but if you compare 2L highres (those taken from dxd master) at various samplerates there should be some difference in the waveforms.
Idk how good is audacity, but i have got some files upsampled with Saracon and it's not the same thing as the original.
Moreover, non- integer upsaming alterates the samples even more.
It's OK, PMA doesn't need to share more than he does. People just don't like the very fact that I am well known and often receive awards for 'Best of Year' etc. along with my colleagues. I am often accused of not sharing enough, and sometimes I am accused of sharing too much! '-) In any case, my best and newest stuff I will not post here. Everything I posted recently is 25-40 years old. Its time to let them into the light of day.
Thanks for pointing out this resource -- I'll have a play with the Hadyn String Quartet samples and see what I come up with ...
Frank
Moisture across 1G is pushing things. B&K took the middle ground for all user apps, with a lower value. Victoreen made the best high value resistors. Mics with tube in same body as capsule inherently drove out moisture.
Nagra had reversed polarity... what did you do about that?
BTW -- i have a B&K 2615 here that i never used -- in original B&K box. no capsule. Anyone need it?
-RNMarsh
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