[mrdrumbeat]

Hi!
I am new to Audio Circle and I need a little guidance.
I have a RM 5 MK II Pre-amp that Roger recently upgraded.  It sounds great!
My question is, I have always used MM cartridges. I now want to try MC cartridges but according to the owners manual, the RM 5 MK II is not set up to run MC cartridges.  What are my choices with this pre-amp to make the transition into MC Cartridges?
Thanks,
Mike

[Roger A. Modjeski]

Hi!
I am new to Audio Circle and I need a little guidance.
I have a RM 5 MK II Pre-amp that Roger recently upgraded.  It sounds great!
My question is, I have always used MM cartridges. I now want to try MC cartridges but according to the owners manual, the RM 5 MK II is not set up to run MC cartridges.  What are my choices with this pre-amp to make the transition into MC Cartridges?
Thanks,
Mike

Hi MIke,

I just approved you and welcome to audio circle.  Actually the RM-5 will work with many MC cartridges as it has a very quiet phono section. As long as you get enough gain in your overall system there is no problem. People often assume you need a step-up for MC but this is not always the case as the gain of your power amp and sensitivity of your speakers also figures in. Also keep in mind your listening level figures in largely. If you listen at 75 dB verses someone who listens at 95 dB that's 20 dB less gain you need. Also at lower levels noise is less of an issue.

I would recommend a cartridge of 0.5 mV or higher. The loading can be accomplished most easily by using a Y connector on each input and a resistor soldered into a RCA plug. We can provide all that for you. We can also provide a 6 to 12 position loading box that goes in series with the phono input for loading. I use one of these myself. If you do go direcct in you should be using our 6922 SLN tubes in the phono stage. They will provide the lowest noise and highest gain.

To get the maximum gain set the line stage to the full 30 dB. Most are set at 18 but the dip switches will allow you the extra gain and the settings are on a label inside. However there will be a great difference  between your CD and phono volume settings. Again there is no loss of performance due to this. I never do anything to sacrifice performance.

For the ultimate in MC listening I made the RM4 pre preamp of which there are many on the used market as well as from us.  That unit will increase your gain and allow cartridges down to 0.2 mV along with easy loading. The gain of the RM4 can be set to anything up to 30 dB and will give about 6 dB increase in signal to noise ratio. I use an RM4 with my Denon 103 loaded at 100 ohms, gain set to 18 dB. I think this is the best cartridge for the money.

[mrdrumbeat]

HI Roger!
Thank you very much for taking the time to respond and for approving me as well.
I have much to learn.  Where to begin?

First off I have an Acquphase AC-3 MC Cartridge with Output voltage at 0.2mV
here is the link to its specs
http://www.vinylengine.com/library/accuphase/ac-3.shtml
I bought this without knowing all its requirements.

Second, I bought 2 SLN 6922+ Low noise tubes for the phono and 1 LN 6922 for the line stage when you did my upgrade to the RM5 in February. You also installed the phono tube off switch, attenuated the tuner input by 8db for my CD player and did some modifications in the power supply for reliability.

Third, I love this pre-amp but being that the MC I bought is 0.2V so the modification you suggested will not apply in this case so it sounds like my best bet is to buy the RM4 pre-preamp.  Is this also known as a headamp as I see on your website price list?

Fourth: Do you have and RM4's for sale?  If so, how much are they today?   And, will I need to buy anything else (cables, chords, etc...) from you to make this work out neatly.  I will be using a VPI Superscoutmaster Turntable. Lastly, is this something I can set up easily or will I need a professional?

Thanks again Roger!   Mike