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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 18th January 2019, 11:38 AM   #51
Bonsai is offline Bonsai  Europe
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Another one to add to your list @billshurv
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Old 18th January 2019, 11:39 AM   #52
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
I realised last night that I have been awfully eurocentric in my consideration of what are the most popular MMs amongst enthusiasts. With no real figures its guestimates and meta analysis but, if you park anything that hasn't been in production for >30years* we can possibly get to a list that covers at least 50% hopefully higher (75% would be great). So in my limited view the big numbers have been shipped by
Grado
Ortofon
Audio Technica
Shure
Excel


Many will not have heard of Excel as a company but their generator is used in a whole slew of OEM carts from the A&R x77 in uk, through to the sumiko MM range and the LP gear vessel models that have recently been released.



Bonsai: I'll get a little panel engraved with room for a few more!




Any I have missed?


*Given the replacements still being sold I suspect there are large numbers of technics carts still in use but I have to draw a line somewhere.


Bonsai: I'll get a panel engraved and leave room for a few more names just in case. A round 10 would be great!
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Old 18th January 2019, 11:50 AM   #53
dreamth is offline dreamth  United Kingdom
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Quote:
Originally Posted by billshurv View Post
My lightest cartridge is 1.5g. How much lighter do you want?
How would longer change the resonances?
I've seen that when the cartridge -tonearms are light most people and also some tonearms manufacturers use some bronze added weight on the headshell to damp the system.The only ones that I'm aware to check their very low weight cart-arm resonance with a computer based ATE system was Bang&Olufsen ...
I never measured that but I've seen many statements about longer tonearm becoming resonant in the audio range.Personally i built some 50-60cm long carbon fiber tonearms(damped with styrofoam double wall cones) floating on water as in the video below and the sound was truly great:
YouTube
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Old 18th January 2019, 12:15 PM   #54
ivanlukic is offline ivanlukic  Serbia
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Originally Posted by Bonsai View Post

If you are a dab hand at software/DSP you could do it automatically with a ref disc or some other clever technique, but really what precisely are you gaining over a classic 5534 all-active RIAA that can be built for probably $2 per channel using half decent passives? Nothing.
+1. Because I tried more than one solution, both DIY and industrial products (phono stages). Beside that, one should have perfectly set cartridge/arm geometry, ideally flat records, first class pressings, etc. that deserve extremely good phono stage. In a real world nothing is like that.

Few months ago my friend and I compared cheap NAD PP1 phono stage with expensive Lehmannaudio Black Cube. I prefer NAD! And NAD uses simple single stage noninverting RIAA with 5532.
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Old 18th January 2019, 12:40 PM   #55
billshurv is offline billshurv  United Kingdom
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MM Input Stage working in inverted mode - not to find; why ??
Quote:
Originally Posted by dreamth View Post
I've seen that when the cartridge -tonearms are light most people and also some tonearms manufacturers use some bronze added weight on the headshell to damp the system.
I think you are confusing damping with resonant frequency. A slab of bronze will not 'damp' anything. It will merely add mass. So for example my SME30H is 5.5g total effective mass including cartridge has the same resonant frequency as a shure SC35 in a BBC MP1/18 12" arm.



Quote:
The only ones that I'm aware to check their very low weight cart-arm resonance with a computer based ATE system was Bang&Olufsen ...
Most used B&K test stuff. Don't underestimate what you could do with that stuff even if it was pre-computer.



Quote:
I never measured that but I've seen many statements about longer tonearm becoming resonant in the audio range.Personally i built some 50-60cm long carbon fiber tonearms(damped with styrofoam double wall cones) floating on water as in the video below and the sound was truly great:
YouTube
It's all about mass and compliance no length.
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Old 18th January 2019, 12:58 PM   #56
Kay Pirinha is offline Kay Pirinha  Germany
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Quote:
Originally Posted by dreamth View Post
-tonearms are light most people and also some tonearms manufacturers use some bronze added weight on the headshell...
Yes, e.g. the Ortofon OM series which weighs 2.5 gr without and 5 gr with that arrow-shaped additional weight that it is supplied with.
I've removed this weight before I've installed the cart to the ULM arm of my Dual CS741Q TT.

Best regards!
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Old 18th January 2019, 01:33 PM   #57
luckythedog is offline luckythedog  United Kingdom
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Originally Posted by Kay Pirinha View Post
MM carts aren't designed for zero impedance loads.
Sshhhh……….no-one told the cartridges that!

Even if just an intellectual exercise, why not? If generator-mechanics coupling isn't even slightly reciprocal, as it isn't, what consequences of pulling 10uA of current or so - in physics terms?

IMO the answer lies in considering whether the coil's inductance behaves differently at 10uA versus 0.1uA peak. Or -50dB below those levels for low level programme content. As an inductor, looking into it from the 2 pin port. To cut a long story short, there's some evidence that it does behave differently, and closer to ideal at the higher current/slew rates. IMHO it's probably about fixed magnetic losses at very small levels. So zero impedance is better...….


LD

Last edited by luckythedog; 18th January 2019 at 01:36 PM.
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Old 18th January 2019, 02:27 PM   #58
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by Kay Pirinha View Post
MM carts aren't designed for zero impedance loads. If a resistor of, say, 47 kΩ is put between the cart and the virtual ground for loading it appropriately, the effective input signal level will be halved, but the noise will be increased. Sure that you want both of them?
The MM electrical circuit does not have an impedance of 47K (real) it has a complex impedance vs frequency and the signal is not simply "halved". The noise is from the real part of the impedance and the 47K load only makes that worse. The virtual ground is simply a win win with of course the need to make your own equalization. Gee it must be 27yr. ago when I published some pre-amp noise plots with a cartridge coil with 47K||250pF load as source impedance, the current noise contribution of a 1nV bi-polar op-amp was pretty obvious due to the real part of the electrical resonance.
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Last edited by scott wurcer; 18th January 2019 at 02:34 PM.
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Old 18th January 2019, 06:24 PM   #59
dreamth is offline dreamth  United Kingdom
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Quote:
Originally Posted by billshurv View Post
I think you are confusing damping with resonant frequency. A slab of bronze will not 'damp' anything. It will merely add mass. So for example my SME30H is 5.5g total effective mass including cartridge has the same resonant frequency as a shure SC35 in a BBC MP1/18 12" arm.

It's all about mass and compliance no length.

A piece of bronze placed on top of the headshell where the headshell is attached to the tonearm will change the center of the tonearm-cart mass closer to the cartridge throwing any resonance between cart-tonearm into the ultrasonic rage while keeping the headshell -tonearm resonance in the subsonic range .
That should be more obvious with stiffer stylus like dj ones or with conical stylus.
Am i wrong about it?
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Old 18th January 2019, 06:30 PM   #60
dreamth is offline dreamth  United Kingdom
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Quote:
Originally Posted by Kay Pirinha View Post
Yes, e.g. the Ortofon OM series which weighs 2.5 gr without and 5 gr with that arrow-shaped additional weight that it is supplied with.
I've removed this weight before I've installed the cart to the ULM arm of my Dual CS741Q TT.

Best regards!
I had an OM-5e, i know that arrow shaped bronze piece, i have two Duals, the 701 and 1219 and i also have a broken one based on ULT tonearm and that is the lightest one, so removing that piece might probably help with that tonearm , i have no ideea how...though.
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