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MM Input Stage working in inverted mode - not to find; why ??
MM Input Stage working in inverted mode - not to find; why ??
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Old 20th January 2019, 06:36 PM   #81
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
Most except Denons, panasonics, Shure, signet. My own fault I hasten to add but I want to properly test drive the concept .
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Old 20th January 2019, 09:46 PM   #82
luckythedog is offline luckythedog  United Kingdom
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If one does go sub-zero, then the issue is exactly what f the lf pole is for any given cartridge, for a fixed preamp config. If it's low enough, far less of an issue and even at 50Hz any error should be audibly small or negligible.

If the cartridge generator copes well or thrives, of course......and generally optimistic yoda is.

LD
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Old 20th January 2019, 10:11 PM   #83
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
The effect of the 50Hz pole moving around a bit is minimal and easily corrected with a simple shelf if required, so possibly not an issue.



As for coping I feel we should test this out
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Old 20th January 2019, 11:46 PM   #84
luckythedog is offline luckythedog  United Kingdom
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Originally Posted by billshurv View Post
As for coping I feel we should test this out
For sure

LD
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Old 21st January 2019, 06:25 PM   #85
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by billshurv View Post
back on coil self resonance not sure if this is of use Moving-Magnet Head Amp - without RIAA appears to show a distinct notch at 50kHz.
FWIW the typical Grado shows the same mid-dip and peak as some of the MM plots with "optimal" loading. Having no luck yet on distributed models for self resonance at audio frequencies, but I'm beginning to believe there are more than one hard to see/measure things going on here.

BTW there are too many phono threads at the moment to keep them all straight.
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Old 21st January 2019, 08:24 PM   #86
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
Way too many. I need to pull some of the good stuff onto a couple of the old threads rather than pollute this one too much.
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Old 22nd January 2019, 10:33 PM   #87
luckythedog is offline luckythedog  United Kingdom
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I'm working on a practicable negative impedance converter sketch schematic. Seems to lend itself well to the 50Hz pole for most MM carts. Watch this space.

Meantime yes the 50kHz notch could be self resonance I suppose......but then the mid band sag is also curious. Most inductance measurements use levels which are way larger than real signal levels.....

LD
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Old 23rd January 2019, 11:23 PM   #88
luckythedog is offline luckythedog  United Kingdom
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Well, I finished a sketch design and it simulates well. However, it is inevitably somewhat 'twitchy' I suppose in that it depends on fairly exact parameters of the cartridge coil, specifically R, and close tolerance components in the preamp. It would also require totally secure cartridge signal connection to avoid the situation where inputs are o/c or dirty contacts to avoid the risk of instability. Or perhaps protection.

I realise that it otherwise fairly well fits the description as per the DisC article, and also that the author says patents have been applied for. So before wading in with both feet I need to visit the British Library and find the application.

So I think I understand why the preferred route might for RB to sell matched cart and preamps?

LD
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Old 23rd January 2019, 11:26 PM   #89
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
And does it show any advantage over a 2L-R configuration?
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Old 24th January 2019, 12:53 AM   #90
scott wurcer is offline scott wurcer  United States
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Originally Posted by luckythedog View Post

I realise that it otherwise fairly well fits the description as per the DisC article, and also that the author says patents have been applied for. So before wading in with both feet I need to visit the British Library and find the application.
Which article, I doubt there is any IP without prior art at this time?

EDIT - found the article, this reads like the strain gauge carts that don't need any equalization at all. RIAA is there you can't ignore it.
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