John Curl's Blowtorch preamplifier part II - Page 3933 - diyAudio
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Old 15th May 2013, 01:01 AM   #39321
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Holy ****, really? It was halfway down your back last time I was over.
Yeah. Got tired of maintaining it so went the opposite route.

se
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Old 15th May 2013, 02:03 AM   #39322
RNMarsh is offline RNMarsh  United States
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Just once -- I smashed a Koetsu Coralstone Platinum cartridge.
Really.

Really?


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Old 15th May 2013, 02:03 AM   #39323
RNMarsh is offline RNMarsh  United States
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No. Thought about it though. Does that count?

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Old 15th May 2013, 02:40 AM   #39324
fas42 is offline fas42  Australia
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Those cartridge warm up sessions getting to you, eh ... , ?
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Old 15th May 2013, 05:30 AM   #39325
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Most mechanical things work better when they are warmed up. Cars certainly do. Some tires, need warm-up. What is the problem? Too much effort?
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Old 15th May 2013, 06:38 AM   #39326
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Most mechanical things work better when they are warmed up. Cars certainly do. Some tires, need warm-up. What is the problem? Too much effort?
My wife too. Worth the effort

jan
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Old 15th May 2013, 09:12 AM   #39327
SY is offline SY  United States
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Originally Posted by john curl View Post
And that is about all they are good for, SY.
No, they're also good for pulling your Porsche out of the mud it easily gets stuck in.

Until you have some experience with the top MMs, you can't really start pontificating about their inferiority based on high inductance, high DCR designs you tried 30 years ago.
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Old 15th May 2013, 03:45 PM   #39328
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I have had sufficient experience with top MM's and I have not only measured them, but I reasonably understand their theory of operation, conveniently brought forth, decades ago, by Shure engineers in 'Audio' magazine.

For everyone who is not up on all this:

A moving magnet or MM is a phono cartridge with a fixed coil (can be any amount of inductance up to 2H or so) that moves a stylus and its cantilever that contains a magnetic material. Sometimes it is called 'moving iron' for this characteristic in construction.
A moving coil is just the opposite, with a large fixed magnetic structure, and a tiny coil, (Ortofon once used 28 turns) that ultimately moves the stylus.

The MM system is by essential design, a 4 pole rolloff system.
The MC is by essential design a 2 pole rolloff system, and invariably has a wider effective bandwidth, with lower attendant phase shift and faster risetime.

In fact, the USUAL electrical resonance of a MM system is within the 20K limit, and is typically OVERDAMPED, in order to smooth the rising MECHANICAL resonance that starts rising also below the 20K limit and the two resonances are arranged to give the smoothest audio response up to 20KHz or so, and then fall at 24dB/oct.
Just look at the page that I put up recently, and compare a typical MM to a MC in bandwidth, there is a BIG difference. This actually gives a MM cartridge another 'degree of freedom' to adjust the frequency response to compensate for 'scanning' losses as well. The MC doesn't normally have this capability, so SOMETIMES the MM cartridge can be made to have an extremely flat response with a specific test record. This can be done by adjusting the output capacitance to make the best response.

While Shure, and most probably other MM cartridge manufacturers have made serious changes to their MM cartridges, the V15-5 being one of the best, the vast majority of MM cartridges follow the MM Shure M91 model more closely, and suffer from severe risetime limitations caused by the 4 pole rolloff.
It HAS BEEN MEASURED, not just by me, but independent sources as well.

Now, what does this have to do about differences between Scott's opinion and my opinion, on the matter of the sound change between two sides of a test record?
That is the REAL question, which I will get into later.
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Old 15th May 2013, 05:03 PM   #39329
SY is offline SY  United States
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I have had sufficient experience with top MM's and I have not only measured them, but I reasonably understand their theory of operation, conveniently brought forth, decades ago, by Shure engineers in 'Audio' magazine.
OK, so it's exactly what I said. You only have experience with high L, high R designs from 30 years ago and are generalizing from those particulars. A modern Grado (which I admit I have no experience with) has a coil resistance of 2R and an L of 2mH. The EPC100C mk4 was 30R and 20mH, flat to 80kHz, tip resonance at about 100kHz, better s/n than any MC I'm aware of.
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Old 15th May 2013, 05:51 PM   #39330
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But it does not not resolve enough! That is why Scott can't tell the difference between the two sides of the same recording. This test record was NOT made just for fun, but to show differences.
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