2. amps-preamps
  3. 184554-182612

UPGRADING HIFI - MC OHMS?

Hi all - I've been a vinyl collector for 17 years and just now have been trying to take it a little more serious and upgrading my hifi system. I am interested to see where the journey takes me, but so far I've gotten KG-4's that I plan to upgrade with the crites cross overs, and tweeter upgrades. My Kenwood KR6160 bit the dust, so I bought a Marantz 1090 - I would like to try a 2240 or 2270 one day, but for now this is what's happening. And just now my B&O MMC E10 finally kicked the bucket as well, so I'm now teaching myself about carts and trying to make a move in that department. Right now I really would like to get an MC cart over an MM - I've found one that I think is up my alley -  an AT-OC9XML but I'm reading all these things about MC's and matching their ohms to your pre-amp that I'm just confused about.

I looked up the phono load for the 1090 and it says 47kohm. The AT-OC9XML cart says "Min. 100 ohms (when head amplifier is connected)" - honestly I don't really know what that means/ what is head amplifier? I guess my question is. Can I get this cartridge and use it with the 1090 and be fine? or is the whole thing about MC's is that you need to get an external pre with switchable ohms to use them? 

 

k thanks! 

billboo1234556
jasonbourne71's avatar
jasonbourne71
1,179 posts
 

The Marantz 1090 phono stage doesn't have enough gain for low output mc  cartridges. Those require a stepup device - an active linear amp (head amp) or a transformer with at least a 1:10 ratio. I use both: a Marcof PPA-1 battery-powered head amp and several transformers: Bellari, Denon, Quicksilver and two custom-built using vintage mic transformers.

jasonbourne71's avatar
jasonbourne71
1,179 posts
 

The Bellari step up transformer is a good budget recommendation! They can be found new on eBay. I am happy with the performance of mine!

jasonbourne71's avatar
jasonbourne71
1,179 posts
 

When using an mc  step up transformer (SUT) keep the connecting cable to the phono input as short as possible. This is so the cable capacitance doesn't load down the transformer's secondary winding and reduce high frequency response. On the other hand, the cable length/capacitance from the cartridge/tonearm doesn't matter with mc cartridges because of their inherently low resistance/inductance.

hotei
153 posts
 

There are very good MM cartridges out there if you don’t really want to mess around with a SUT.  Ortofon or Nagaoka are good ones.

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