SUT With a Manley Steelhead RC?

@lewm- two comments. First, I agree that there is no absolute in matching numbers -impedance of cartridge to primary or input of SUT. I’ve experimented in each case, both on the Allnic and on the outboard unit I use in my vintage system.

Your observation that the SUT does not present a load is intriguing to me. My goal in the above statement was to demystify some of this stuff and simplify it, so it didn’t seem like a dark art. Thus, I used the terminology with a nod toward you.

I do often refer to the setting of the primary or input as the "load" the cartridge sees. I’m also reminded of the occasions where people talk about "loading down" a cartridge as opposed to running it wide open, i.e. 47kOhms.

Thus, this explanation (from a site called "hi fi for lo-lifes"-a moniker that amuses me), speaks in just such terms:

"These passive windings have ratios. These ratios operate as approximations to specify a SUT for matching with specific cartridge impedances. Standard ratios tend to be 1:20 or 1:10 (this is the “gain” usually translated to dB) but numerous ratios exist for differing cartridge specifications, and many SUTs feature multiple winding ratios to add flexibility for different carts (a 1:20 SUT may also include a setting for 1:40 windings). A general rule for MC carts is they prefer a load impedance of 3~6 times their output impedance (for example, a 20-Ohm output impedance cartridge would work well with 60~120 Ohms of input impedance). A 1:10 winding ratio means that the secondary winding has 10 times the number of turns of the primary winding, so the voltage for the secondary is roughly 10 times that of the primary. But, that’s not all the magic the transformer is performing, it is changing the resistive load the cartridge “sees” by squaring the turns ratio divided into 47,000 Ohms (this is the impedance). This translates to the cartridge “seeing” a load impedance of 470 Ohms instead of 47,000 Ohms, a number most MC carts are quite happy with."

I’m comfortable with that explanation. Tell me where I’ve gone astray- not to argue, but to inform. Ty.

Sometimes it's a matter of semantics, but many do speak of SUTs as if they have an impedance of their own.  This is not the case, so I am sensitized to that implication.  As I know you know, any transformer merely converts current to voltage (if you think primary to secondary), and the impedance seen by the cartridge is simply a function of the impedance present on the secondaries.  The SUT adds no impedance. (This is in a perfect world; in reality there is a tiny effect that can be disregarded for loading a cartridge.)  It's obvious that you have a handle on it, so I apologize for my pedantry in correcting your original statement. I just know some others might have been led astray and was trying to prevent that.

For one thing, if you have a cartridge with a high-ish internal resistance, like a Denon or some Benz cartridges, such that it is not an easy match for a SUT, there is no reason you can't replace the 47K resistor at the MM input with a 100K resistor or even higher, to make the cartridge happy with the final impedance it has to drive.

@lewm No insult taken. My post about 10x sounded somewhat absolute so that was fair ground. We’re good.

@car123 Per your suggestion, last night I connected the TT to the MM input of the Steelhead and maxed the gain.  At first I kind of liked it, because there was excitement in the sound, but after awhile I couldn't listen anymore and switched it back. to the MC input.  The noise floor seemed much higher in MM.  After I switched it back I thought I should have tried backing off the gain to see how it sounds, so maybe I will try that soon.  Your suggestion had been mentioned to me previously when I first bought the Manley, so I know it has merit.  I just wasn't happy with the first attempt.  I appreciate your help

IME, loading is all about gain.

I don't worry about it too much.  Low output low impedance.  High output, high impedance.  That's about it.

It's one detail I don't sweat.

The only reason to put a SUT on a Steelhead, IMO is to bypass whatever Manley is using in the gain stage.  Might be more quiet, might not.  Just me, but if the MM side is not black, that's not a good sign.

YMMV