MM Phono input vs. MC Phono input

[quicksand]

You have a LOMC cart at .3mv
You use a phone stage for LOMC with a 15x gain in voltage
Your signal is now 4.5mv which is decent for line level input
No stress on the phono stage or the amp

Now try the same with a MM cart that STARTS at 3.0mv
You use a phone stage for LOMC with a 15x gain in voltage
Your signal is now 45mv (versus 4.5)
You risk damage to the following:

The phono stage is probably not made to accept a signal above 1.0mv so you risk damage there feeding it 3.0mv

if the phono stage survives, you are pushing a huge gain at the amp - 10 times what it should be

You'll also be pushing extreme noise

Does this help ?

Thanks Rob,

I understand what you are saying and the concept of overloading. The ol' proverbial 10 pounds into a 5 pound sac... I was trying to put my finger on if anything could be harmed using the high output cartridge into a low input - you summed that up well and the answer is yes it will.

Some how I had it in my head that the volume control would help me here. I knew the higher gain would be present - just I wasn't sure if it would cause damage other than distortion.

Thanks again for helping me beat it into my head!

 

[Tedrick]

Thanks, Rob. Excellent explanation.

 

[62sunbeam]

Look up the prescribed loading on vinyl engine. I'm sure you are within the prescribed tolerances but they list resistance loading specs for almost every cart and yes it makes a big difference with MC carts.

This is why I like my B&K MC101 so much. It has sockets for changing out the resistors and the range for MC carts can be huge.

Enjoy

Eric

 

[arcorob]

No worries..

Glad to help...

Now...lets get you into a nice LOMC...LOL