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Welshsox
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MM, MC, beginners guide

Hi

The whole MM MC voltage output and loading thing is a little confusing when first encountered. It appears as if you have to not only match the input voltage but also the input impedance of the phone stage to the cartridge.

Im sure this has come up numerous times, could someone point me towards a good article or narrative on the subject please.

Thanks

Alan

linden518
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Re: MM, MC, beginners guide

Hi, Welsh. This following article's actually on phono stages & keep in mind that it's from Graham Slee, a manufacturer of phono pres... but it's actually a pretty objective and insightful read. There's stuff in there about phono pres, but some good primer on MC vs MM. I know most audiophiles champion MCs, but MM carts can be fantastic. If you are starting out especially, you might look into a quality MM first.

http://www.gspaudio.co.uk/phonopreampstage.htm

Consider, for example, this review of Clearaudio Virtuoso Wood MM cart by Robert Reina (I ended up buying this cart.)

http://stereophile.com/phonocartridges/737/

I'm sure if you poke around here & there, you'll run into more articles. Good luck!

piinob
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Re: MM, MC, beginners guide

I got pretty mixed up on this myself a while back. I went in search of a book to help me understand a lot of the lingo and concepts being bandied about here and there in the audio world. Robert Harley has written a kind of Audio High End Primer called something like All about High End Audio. I got a copy from Amazon, but I have seen it all over the place since then. It seems to be pretty factual. RH used to write for this magazine, and now writes for the competition. Maybe Mike Fremer, or Art Dudley, or Kal Rubinson will write an analog primer for us. MF has a great video on Cartridge setup. Hope this helps.

bertdw
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Re: MM, MC, beginners guide

A bit more detail on moving coil cartridges. You may want to jump down to the "Step-up devices" section.

http://www.6moons.com/audioreviews/stepup/primer.html

dcstep
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Re: MM, MC, beginners guide

Keep in mind that there are two sub-catergories of MC, High Output MC (with around 2.5mV of signal) and Low Output MC (lower than 2mV). HOMC does NOT require a step up device, which can introduce noise that's hard to get out. Sumiko Blackbird, Bluepoint and Benz Glider are examples of excellent HOMC cartridges that you might consider before you go off the "deep end."

Dave

tom collins
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Re: MM, MC, beginners guide

i agree that the high output mc is a great compromise with most of the goodness of mc and the advantage of not having to introduce another variable into the system. i am using a benz myself. however, with that said, in my personal experience, i still have to turn the volume about 20% higher than with a cd for comparable volume. if your head unit does not have a built-in phono card, then there is a huge variety of phono amp units in all price ranges to choose from but keep in mind you will still need to buy good interconnects. i think that if you have a good, but not spectacular system, the high output mc is a very good option to explore. have fun exploring.

tom

dcstep
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Re: MM, MC, beginners guide

Yes, good ICs are important. Even with good ones, eliminating one set is a good thing.

Dave

tom collins
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Re: MM, MC, beginners guide

i agree, dave. btw, did you read the article on the songsmith "moving iron" cartridge? any experience with those? sounds like an interesting concept, would like to know how it compares with the black bird.

Welshsox
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Re: MM, MC, beginners guide

OK

After reading the articles its clear that impedance matching is key.

As a temporary measure i was trying to use a DV20X high output MC into the MM stage of my receiver. It sounded like crap, thick heavy bass and nothing else.

I have a new system coming shortly with a proper Mc preamp input stage, hopefully this will help things immensely !!

Alan

dcstep
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Re: MM, MC, beginners guide


Quote:
i agree, dave. btw, did you read the article on the songsmith "moving iron" cartridge? any experience with those? sounds like an interesting concept, would like to know how it compares with the black bird.

No, I'm not chasing that one. I remember some reviews of moving iron a few years back, which seemed to have high potential, but decided to stick with "mainline" cartridges. The Blackbird really seems to work well with my Pro-ject's arm, so reluctant to mess with that.

Maybe you could try it out and report back.

Dave

piinob
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Re: MM, MC, beginners guide

Didn't I read a while back that you have the Pro-Ject 10 TT? I have a 9.1 with a Blackbird and it is a great match.

dcstep
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Re: MM, MC, beginners guide


Quote:
Didn't I read a while back that you have the Pro-Ject 10 TT? I have a 9.1 with a Blackbird and it is a great match.

Yes, I love my RM10 and the Sumiko Blackbird. The new phono cards in my Rowland Continuum are also very sweet and incredibly quiet.

Depending on what you already have, you might consider the Pro-ject isolation base. When I've done with/without comparsions it's very effective. Also, the Speedbox II really works, if you don't have that.

Dave

KBK
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Re: MM, MC, beginners guide

Oneof the near rules, is that for the best results with low output MC's (AKA: LOMC), one of the the best ways -if not the best way- to amplify the signal from them is via 'step-up' transformers.

The key here, is to look at the so-called 'impedance rating on the actual coil itself, not the manufacturer's 'load'rating.

For example, I've 'de-nuded' my Goldring Eroica LX (Low output) MOC coartridge. I took the plastic body off it, and then damped the remaining structure with the older series of 'dynamat' material, their best stuff which become to expensive to make, the green coloured stuff. Sounds OK. I could do better on the damping front.. sure, but I can't be bothered right now.

The rating of the coil's impedance is '2 ohms', and I've coupled it to a transformer from M.A.Cotter (a silver wound and potted unit)that has a 'load rating' of 2 to 10 ohms, with regards to the cartridge 'coil impedance'. This is an important point. Transformers have to be matched to the coil impedance to have a good energy transfer that is not phase and frequency shifted.

In my case, it's cheaper to get a new LOMC than a new transformer, as the transformer is worth more.

Another thing, is that LOMC's need be 'de-magnetized' on semi-regular basis to sound their best.

http://www.needledoctor.com/Aesthetix-AB...34Pa38Ta3aKaNz0

The overtly anal can futz with it and demagnetize often, if they wish. Keeps them happy.

AJ has a 60 page! FAQ article on phono cartridges. Check it out.

http://www.vandenhul.com/Default.aspx?page=p&id=29

piinob
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Re: MM, MC, beginners guide

I had heard that the base really improves on things. It may be the next investment I make. Right now I am leaning towards a Cleaning machine, but I scrub pretty well.

linden518
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Re: MM, MC, beginners guide

Another primer on LOMC and SUTs:

http://www.vinylengine.com/step-ups-and-mc-cartridges.shtml

Which might push you toward waiting on LOMC until you're more familiar with analog set-up...

Elk
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Re: MM, MC, beginners guide


Quote:
The key here, is to look at the so-called 'impedance rating on the actual coil itself, not the manufacturer's 'load'rating.


However, if I recall correctly, don't try and measure the resistance yourself with the typically multi-meter as you will fry the coil. The multi-meter's reference voltage/current is too high. Correct?

bertdw
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Re: MM, MC, beginners guide

I'll second that, Elk. NEVER measure a moving coil cartridge with an ohmmeter. I won't even do it to a moving magnet cartridge.

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