MM vs. MC Adavantages

[jcmusic]

I am using a MM cartridge now, what advantages would there be if any for me to go to a MC cartridge?

Jay

[Allan Songer]

Does the Rogue have a MC input? If so, then I can't think of one reason why you should contnue to use a MM cartridge other than making the switch will make you poorer!

[garymd]

What Allan said.

As long as your preamp has a built-in step-up transformer so you have enough gain for a LOMC there's no reason not to try one. I don't know technically why there's an advantage but every one I've used seems to be more transparent, musical and just better overall sounding than most MM's. You might want to give the inexpensive Denon a try first. Killer cart for the money. It won't sound as good as a $2k or $3k cart but it might suprise you and sound better than some of the $500-$1000 MM carts out there.

Good luck and let us know what you end up doing.

[lwhaples]

Jay,I have two Thorens TD MKII 160's.One with a MM one with a MC,right now I have to use the MM.The Blueberry has to be looked at,and I REALLY miss the MC cartridge. Well worth looking into.

Larry

[jazman]

I am using a MM cartridge now, what advantages would there be if any for me to go to a MC cartridge?

Jay

Almost everything you need to know about phono cartridges can be found on the Van den Hul site. There is a section on MM vs MC cartridges.

http://www.vandenhul.com/artpap/phono_faq.htm#1

Klipsch out.

[jcmusic]

Allan yes it has two switches for low and high position. Depending on the output of the cartridge, determines how to set them. Also you have the option of changing tubes for more gain if need be. 12AU7, 12AT7, to 12AX7. In looking at the owners manual I to be 0.4mv and up.

Larry thanks for the tip.

Here are the specs. frequency response: 1Hz-200KHz ± 1dB
- THD: <0.1%
- gain: line stage: 23dB
- gain - mm phono: 65dB
- gain - mc phono: 75dB
- RIAA accuracy: ± 0.1dB
- rated output: 1.5V
- maximum output: 30V PP
- output impedance: 350 Ohms
- dimensions: 17"W x 5½"H x 14"D
- weight: 27 lbs.
- shipping weight: 32 lbs.
- power requirements: 115/230V - 50/60Hz

Jay

[edwinr]

The Denon DL-103 is a brilliant beginner's MC cartridge. Some have suggested that the Denon is not an ideal match for the Rega RB300 arm - but I've had no problems. The tracking is superb and the smoothness and 'air' of a good MC is so much better than the equivalent MM.

[whell]

For those w/o a MC input on their preamp, or a step up transfromer, what about a high output MC cartridge?

[LarryC]

I agree with the praise for MC over MM carts. Beyond that, the lower-output MCs (LOMCs) often have transparency advantages over higher-output (HOMCs), and you are likely to see forum members and phono freaks gravitating toward LOMCs for that reason.

I guess representative outputs are 0.3 mv to 0.6 mv for LOMCs, vs. over 1.0 mv for HOMCs, although some on the forum may disagree with the ranges I suggest. Anyway, I once had a high-output Benz Micro for a short time that I thought sounded absolutely opaque -- yuk!

I would guess that the Rogue specs show total preamp gain for mm and mc's rather than separate figures for line and phono stage gain that need to be added together for the total. I think most manufacturers would look at the Rogue figures and say the line stage is 23 db, the MM stage has 42 db (65 minus 23) and the MC has 52 db. If so, the total gain for MM carts is in a customary range, while the total gain for MC carts might be best for "medium output" MC's, but might not be adequate for, say, a 0.4 mv LOMC cart. My former CAT preamp had 46 db phono gain and was not quite adequate even for 0.7 mv carts. My current preamp has 61 db phono gain, which works much better for that kind of output level.

The whole challenge of tailoring cartridge output, phono stage gain, line stage gain, and even amplifier gain and speaker efficiency, can be a bother until until you successfully work it through. While I think its "optimum gain" figures are too low, this interesting site (click "Preamp Gain Computer" on the left side of the page) might be of some help in sorting out the amount of phono gain needed for a given MC output voltage. Again, this is phono stage gain, not the total gain you see in the Rogue figures. BTW, some aficionados go by matching MC cart impedance rather than gain.

Larry

[garymd]

If you're going to go the MC route, I highly suggest low output. My experience with HOMC wasn't much different than a decent MM. Seems most of the benefits are found in the low output models. I'm sure there are exceptions. This was just my personal experience. The HOMC's I tried sounded very nice but didn't give me the "WOW" factor I found with high quality LOMC's.

[djk]

"I am using a MM cartridge now, what advantages would there be if any for me to go to a MC cartridge?"

A typical MM cartridge has a source impedance of about 1K ohms.

The maximum signal-to-noise-ratio will be on the order of 65dB.

You will hear more dynamic range than this due to noise modulation (similar to digital dithering). I have heard demonstrations of audibility of up to 40dB below the noise floor.

The lower the source impedance, the higher it is possible for the s/n ratio to be. Going to 100 ohms can gain you 20dB, going to 10 ohms can gain you 40dB, going to 1 ohm can gain you 60dB. The lower the source impedance, the lower the output. This means we need a step-up device.

'Can gain you' is dependent on the noise of your step-up device. A transformer is generally quieter, a gounded-base amplifier is also good.

Douglas Sax of Shefield Lab says there is 134dB of recoverable dynamic range on a direct-to-disc record. Masters from tape are a variable with track width and speed, no where near as good as DD. Red book CDs are based on eight-to-fourteen modualtion, -84dB is digital zero. You can pick up a couple of dB from the Nyquist sampling theorem, and a few more from dithering, but while the s/n ratio is higher than phono, the dynamic range is not.

Grado and Stanton used to make low source impedance MM cartridges that sounded like MC, and also required a step-up device. I heard a Grado that sounded identical to the Denon DL103D, but it actually cost 3X as much.

[maxg]

Move the magnet or move the coil. For a given output level the magnet is actually lighter than the coil, however, if you are prepared to accept a lower output level then a coil can be made to be lighter than a magnet can.

The above is almost entirely the logic behind the mystique. Low ouput MC cartridges are moving a tiny coil through a magnetic field and producing a very small output (typically less than 0.5 mV). An MM cartridge can produce a much higher output - 5 mV for example - or 10 times as much requiring, consequently, less gain from the phono stage.

The theory behind LOMC is that the smaller the mass of the thing you are moving - the coil in this case - the better the response of the cartridge to the sudden demands of music reproduction.

In other words - you should get more detail out of a LOMC cartridge than is possible with a typical MM, whilst picking up a more musical effect of the music - a win win.

That is the theory - and one I happen to agree with in practice - but YMMV and all that.....

[Parrot]

A typical MM cartridge has a source impedance of about 1K ohms.

The standard input impedance for MM is 47K.

[maxg]

I am trying to figure this out in my mind as I type - so bare with me.

I think the lower source impedance of an MC cartridge is actually a result of its lower moving mass. The source impedance is, I think, the measure of the "work done" to move either the magnet or the coil. Lower mass therefore is the same as lower source impedance - I THINK....

I am going off into a corner to ponder this one - I think it is right but I am not at all sure. If anyone can save me from this deep thought - fire away...

Edit - Not happy with the phrase work done - resistance to motion or interia is probably a better way to explain it....still thinking....

[jcmusic]

Mark based on the spec's supplied by Rogue, what do you think would be the best I can do in a MC output? How low can I go before I am too low?

Jay

[thebes]

Quasi Hijack. Interesting topic. I've been wanting to
try a Denon dl103 in my downstairs setup which utilizes a Conrad
Johnson PV3 which somebody told me could handle a MC. I'd
also like to try it with my new toy a Harmon Kardon TT.

I'm also concerned that at 8.5 g this might be too heavy
for my low mass arm. I'm also concerned about overhang because
when I tried mounting my Shurt v15 Type II the overhang was too great.

Here's the specs on all 3:

CJ PV3 Specifications:

Gain: Phono Stage 38 dB
(phono overload 500 mV at 1kHz)

Line Stage 26 dB

Distortion: less than .05% THD or IMD

Response: bandpass 10Hz to more than 100kHz

RIAA equalization: +/- .5 dB (20 to 20 kHz)

S/N Ratio: Phono Stage 70 dB below 10 mv input

Line Stage 84 dB below 2.5 volt output

Phase Response: Line Stage phase inverting, Phono Stage (at tape-out) phase
correct

Mechanical: 10" x 3" x 7"

Denon DL-103 Cartridge

• 
  
• Output: 0.3 mV
• Output Impedance: 40 ohms
• Stylus: 16.5 Micron round tip
  
• Frequency range: 20
  Hz to 45 kHz
• Tracking force: 2.3~2.7g
• Compliance 5 x 10-6
  cm/dyne
• Weight: 8.5g
  

Harmon Kardon T35C TT

Effective Tonearm Mass: 8g plus mass of cartridge

Stylus Overhang: 18mm

Effective Length: 216mm

Phono Capacitance: 160pf

Acceptable Weight of Cartridge: 3-8g

If it won't work in this situation can I still use
my PV3 with an MC or do I need a step up transformer, and if so does it
matter if the adapter/transformer is tube or SS since right now I
am all tube.

[jcmusic]

OK guys I just recieved an email from Rogue stating that the 99 will work fine with a 0.7mV and up cartridge, so where does that leave me? What are my options in this range?

Jay

[maxg]

Marty--

Your preamp has a MM phono stage and will not interface well with a LOMC. You really need an LOMC stepup. Yes, you can plug the Denon into your MM stage, and yes, it will play, but certainly not in an ideal sense.

Additionally the Denon is not ideal for a low mass arm as its compliance is too low - better suited to medium to high mass arms.

[jcmusic]

Mark thanks alot you have been real helpful in my pusuit to better sound.

Jay

[jcmusic]

Ok guys I am going to stay where I am for now, after I upgrade to a nicer TT I will try the MC route. Thanks for everone's help in helping me understand about MC's.

Jay