AudioCircle
Industry Circles => Vista Audio => Topic started by: neobop on 21 Mar 2013, 09:20 pm
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Great article from 2008.
http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html
Preferred load for M-97 is 62K, 250pF
AT-440MLa - 32K, 150pF
AT-95E - 47K, 150pF
Clearaudio MM - 47K, 100pF
Denon DL-160 - 1K to 47K
Stanton 981LZX - 250 ohm
Pickering 7500 - 250 ohm
Ortofon M20FL Super - 53K, 300pF
Ortofon M30, 40 - 39 to 47K, 200pF?
All subjective What's your load?
neo
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Very useful link - thanks for posting!
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Here is an RTA plot taken at the listening position using Hifi News & Record Review Test Record pink noise track.
The cartridge is an AT 440 ML with the inductance of the coils canceled out. I used REW and the Dayton Audio UMM-6.
(http://www.audiocircle.com/image.php?id=77501&size=large)
The pink noise on the record appears to start at 15Hz on the low end
(http://www.audiocircle.com/image.php?id=77502&size=large)
Obviously we would know more if I could measure the response electrically from the output of the phono stage rather than acoustically at the tail end of the chain at the listening position.
At this point I couldn't tell you if the record is flat out to 20kHz or not.
Scotty
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Very useful link - thanks for posting!
Hi Boris,
The fellow who wrote that article is an EE. He occasionally posts on VE and Asylum. He also contributed to a thread on VE called Cartridge Loading Explained. It was started by CarlosFM (another EE) a few years back. Here's the latest, page 21. Check this out:
http://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=6674&sid=95d671cacdd2cce7eb87766ae61f56e0&start=300
neo
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Here is an RTA plot taken at the listening position using Hifi News & Record Review Test Record pink noise track.
The cartridge is an AT 440 ML with the inductance of the coils canceled out. I used REW and the Dayton Audio UMM-6.
Scotty
Hi Scotty,
Do you remember which thread on vinyl circle where you first posted this?
This involves the use of a second, "identical" cart.
neo
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That's the thread you started on moving magnet phase shift,
http://www.audiocircle.com/index.php?topic=92138.0
Scotty
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You guys got me thinking... Perhaps it would make sense to have a simple circuit that would make it possible to use regular DMM to measure linearity of the cartridge/preamp output, using test records. Nothing unheard of, precision rectifier followed by a low pass filter would probably do the trick - get accurate DC output proportional with the amplitude of the test signal. Of course, devil is in the details - there is a good reason why wide bandwidth accurate voltmeters cost enough not to be part of a typical audiophile's toolbox of tricks. But I'll think some more tomorrow, it's been a long day for me....