Phono stage advice

I want to run two turntables into one amp and the best way to do this would appear to be to run one straight into the amp phono input and the other via an external phono pre amp into a line input.
One T/T will be an old Dual unit for playing mainly 45’s and the other will be my “good” single speed T/T used for 33 only, both have MM cartridges at the moment. As I intend to upgrade to MC on the better T/T at a future date, the external MM phono stage seemed a good idea as I could upgrade to an external MC stage when required.

The amp is a Marantz PM66SE KI which I believe has a reasonable Phono stage anyway. Question is, can someone recommend a reasonable MM phono stage, self build, kit or ready to go, for use as an external unit. I don’t need anything esoteric so don’t want to spend the earth. The other question is, would I be better using the Marantz phono input for the better T/T?
 

cr0wl3y

Member
2009-09-17 10:27 am
A magnetic phono level switch will create quite a "click" when you switch inputs.
Your idea of using an external phono preamp into a line input makes sense.

That's true but can always take volume down or switch the amp input into something else during the time you switch. I'd definitely prefer to do that than compromise with a substandard phono stage or shelling out a couple hundred £/$ for a decent one.

Exception: given you want to try non-high output MC eventually, you could get a switchable MC/MM stage and skin both cats in one go.

I don't know what your amp phono stage sounds like, but I strongly advise against a cheap (<£/$100) DJ mixer, they really don't sound good. A second hand entry-level Graham Slee stage would be a better and not much more expensive option.
 
Sorry, by noise I meant hum from unshielded connections. I would not have the amp selected to phono while I switched so no worried about switching noise.

I may initially get a good quality switch and build it into a shielded case with phono sockets. I will obviously have to get an external MC preamp when I get an MC cartridge. Do most MC pre amps have line level outputs or are they at MM levels for feeding into an MM input?
 

cr0wl3y

Member
2009-09-17 10:27 am
You do not necessarily need a dedicated MC preamp, you can go down the passive route of using MC tansformers to bring the MC output to the required level. There are commercially available options or you could simply buy the transformers and put them in a suitable housing.

You can spend as little as £50-100 for a pair of "naked" second hand transformers on ebay or, for commercial products, anything between a couple of hundred to a couple of thousand quid, for the more esoteric or "trendy" stuff. Search for "MC transformer" under consumer electronics and you will see a wide range. Unfortunately I have never tried any of this at home so I cannot offer an opinion on what is good and what not.

RE shielding, you can use a metal housing or, if you want to make a pretty wooden box, foil the inside and connect it to ground and you should be fine. A nifty way to deal with both issues (selection and MC) would be to do everything in one box and either wire the transformers into one of the two inputs or "true-bypass" it with a 4pdt toggle switch before or after the input selector switch, for added flexibility.