7C phono section. Step Up Transformer or no need?

[Megaladoink]

So ive got a Marantz 7c and im rocking a .3mv Moving Coil cartridge. Do i need a step up?
I noticed that I do have to crank the volume up.
If so what it the ratio i need and any recommendations?

 

[dankik]

Here are the specs for the Phono 1 and II inputs on the 7T. Both inputs have a sensitivity of 3.3mV. A MC cartridge has about 0.1mV - 0.5mV output. About 6-7x too low.

https://community.klipsch.com/index.php?/topic/191103-phono-stage-minimum-input-voltage-marantz-7-preamp/
It's not easy to connect a MC cartridge to an amplifier MM phono input. Here are the typical electrical differences.
Apparently, it is also difficult to match the impedances to get a flat frequency response.


https://vinylrestart.com/mm-vs-mc-phono-preamps-explained/
You could buy an external MC preamp and connect it to the Aux input to your amplifier, but this is a little pricy
For that price, you might consider buying a good MM phono cartridge to replace your MC.

 

[Megaladoink]

so when looking at transformers, what should the ratio be?, im seeing a new 1:20 transformer. is this way too much?

 

[gadget73]

0.3mv through a 1:10 would give 3mv output. 1:20 you'd get 6mv.

loading is the other side of that. Impedances square, so with a 1:10 into a typical 47k load you'd get a 470 ohm load at the input to the step-up. With a 1:20 you'd have 118 ohms.

Not sure what the specs are for the 7C, it would probably be OK with 6mv of input but find a spec sheet and confirm that. So long as its greater than 6mv it'll work, you just don't want to overload the phono input.