Mark Levinson No 52 Preamp phono stage custom loading

Perhaps similar to No.32 using a pair of screw terminals?
Mark Levinson Nº32 Phono Manual

I learned here last year, it takes some research to get it. Then, if like me, I forget what I learned.

Take it apart, look at it, see how they physically change, then: STOP!
research your cartridge, then change settings.

47K is for the majority of MM cartridges, it’s like PASS on a SUT if running a MM thru it.

The lower ohm settings are for various low output MC cartridges (LOMC), each having two important specs:

signal strength ( .. mV;) needs boosting (x factor)

internal resistance ( .. ohms) needs/becomes boosted (relative to x factor squared)
this is the trickiest part. result is what resistance is ’shown to’ the MM input.

the ’starting goal’ for ’shown impedance’ is: cartridge internal impedance multiplied by 10. then, up or down from there.

i.e. my AT33PTG/II has signal strength .3mV and internal resistance of 10 ohms.

I need an x factor high enough to get the signal high enough for my MM Phono input
and, I would like to have the impedance shown to the MM 47k input to be around 100 ohms.

x factor effects the impedance by a formula involving x-factor squared.

I better stop now, anyway, take it apart!

Perhaps similar to No.32 using a pair of screw terminals?
Mark Levinson Nº32 Phono Manual

@imhififan Thank you very helpful!

It dawned on me that I should be able to also set the load to the option of 47K, and then use loading plugs. Example 900 ohm resistor used on a loading plug (1 male RCA to dual female RCA) would give me ~900 ohm resistive load?

what are your cartridge(s) signal strength and internal resistance?

SS Hyperion. I want to be able to resistive load between 470 and 1000 ohms. Loading plugs using 47K stage setting would be easier maybe to find what I like. Then I would use the internal screw terminals (if they exist in the No 52).

@dnicol  

If you're talking about plugs that have a female input to a male output with a 900 ohm resistor from hot to ground, then that will work.  

But before you do anything, try listening to your cartridge with no additional loading.  I've been using MC carts, including some expensive ones, for years without any added loading.  You might be satisfied with the sound without any loading.

@bpoletti Thanks. I have been listening to the cart using a different stage that has variable loading, and no loading, etc., Soundsmith's loading recommendations for me are pretty spot on. The ML stage may be better, might be worse or lateral, but I will never know unless I can load it the way I want, and in the end if it has an internal custom loading option, for me that would be the best way to load after I find how the cart reacts to a different stage.

You are MUCH better off using the ML option, because every resistor type has it’s own sonic signature. I have tested extensively in my own phono stage, and the results range from sublime to unlistenable. The worst was the most expensive resistor and the 2nd best was the cheapest.

The clear winner, to my ears and with my system (ESLs, custom SS class A electronics, air bearings, Koetsu) was nude Vishay. Costs less than $50 the pair, and it makes the biggest difference in the system, at least as much as your ML phono section. Does ML still use aerospace MAT series transistors from Analog Devices for small signals? I use complementary MAT’s and nude Vishays wherever I can from phono to power amps.

I use a loading of 500 ohms for the Koetsu for most material, but more if it’s organ and less if the cartridge is cold. Why not get a few pairs, say 100, 500, 2K5, 10K and test? It’s the best use of money you can make - but beware, the nudes are FRAGILE.

Do let us know what works for you and that lovely new Hyperion.

All of this IMO. YMMV.

Should have added, that's 500R with no SUT, just straight in.

@terry9 If you are referring to the No52, could you tell me how/where the custom resistive loading is done? Are there screw terminals somewhere like the 32? Thanks.

Sorry Dnicol. I was referring to my own electronics, DIY. I built in 20 cartridge loadings from 5R0 to 86K. That feature cost me $1000 in parts, but was well worth it.

@terry9 Curious, what were the most expensive and the cheapest?

I do have some 2575’s on the way, so far found dirt cheap chinese metal film 10 for 75 cents to sound better then a dale cmf55 or pink takman!

The worst was the most expensive resistor and the 2nd best was the cheapest.

Don't recall specifics, but they looked impressive, were MILSPEC and cost $50. The inexpensive were noname Taiwan, I think - $.01 back in the day in a big bulk lot.

You've started on a most rewarding journey. It led me all the way to ground up DIY. Good luck!