Which SUT? .... for .3mv/10 ohms MC cartridge into 3mv MM input sensitivity

Please help me choose a SUT for my 1st MC cartridge.

Now I have more than enough volume using my existing MM cartridges thru my mx110z MM Phono input which says sensitivity 3mv/47k ohms impedance.

AT440ml is 3mv.
Shure 97xe is 4mv
Shure V15VxMR is 5mv
Grado ME+ Mono is 5mv.

coming tomorrow: AT33PTG/2 MC .3mv/10 ohm coil impedance/dc resistance


signal boost, am I getting it right?

1. Is 3mv a MINIMUM strength for the mx110z input?

2. .3mv x 10 = 3mv (+20db correct?) (minimum boost therefore x10/+20db)?

3, if correct, is .3 x 20 = 6mv equiv to +40db?

4. if so, a SUT providing +40db is more than enough for the .3mv and any likely future MC?

impedance/loading: I am not getting it.

I read about a general rule: coil impedance x 10 for ____?
A33PTG/2: 10 ohm coil x 10 = 100 ohm

too high impedance sounds thin? bright?
too low impedance sounds dull?

(how?) (minimum?) (where?)

Thanks as always, and this time I will definitely wait for advice before getting anything. I am not in a hurry for this, Bill will loan me one of his SUT’s until I get my own.


Cartridge just delivered, ordered 2 days ago. Amazon Prime is a waste of a lot of fuel for single item deliveries, but nice when you want it quick.

I jerk myself around when learning new stuff, so thanks for all your patience. And I always imagine others learning like myself following along

certainly I like the features of the Denon AU-320, and you have all given me confidence,

not to mention, Bill will be bringing his Denon SUT, that's what I will hear for the first time.

Nice to know 6mv is not too high. Changing the volume is easy, using 11 o'clock with 5mv shure now.

I just found an Ortofon ST-7 (single input, no bypass) it's specs:
Frequency response: 15-45 kHz (+0 dB -2,5 dB)
Gain: 24 dB at 1 kHz
Recommended cartridge impedance: 2 Ω - 60 Ω
Recommended load: 47 kΩ // 200 pF

chart I found converted +24db to 15:81x
result then 4.75mv (before loss); 188 ohms

I like how many Denon's are for sale, not too costly.

Yes, Bob's Devices Sky looks awesome, I am hoping to keep the cost down

AT-650, I like the three options 3, 20, 40 and it has Pass, the 20 input gives an optional/potentially preferable sounding choice. (for this or future MC after I get hooked, the Pandemic never goes away, I keep wearing out cartridges!!!

this fidelity research FRT-4 is quite versatile
don't anybody buy it, I might buy my 75th birthday gift 3 years early

3 inputs; 3;10; 30; 100 settings AND Pass



ManufacturerFidelity-Research/ Fidelity ResearchModel number: FRT-4.
specificationModel Model MC Cartridge Toroidal Core Step-up TransformerNext Impedance 3 ohm/10 ohm/30 ohm/100 ohm switchPASS(selectable) Load impedance 47kΩ to 57kΩ 50kΩPressure increase3Ω:31.1dB(35.84 times)10Ω:26.3dB(20.68x)30Ω:25.2dB(18.27 times)100Ω:20.0dB(10.55 times)
Frequency response 20Hz to 30kHz
Distortion Within measurement error range up to 2 Vrms of output voltage
External dimensions: 170mm (W) x 60mm (H) x 180mm (D)
Purchased new decades ago.Price at the time.54,000 yen (circa 1978)

this fidelity research FRT-4 is quite versatile
don’t anybody buy it, I might buy my 75th birthday gift 3 years early.

I certainly won’t be buying it :-)

Even if I needed it, which I don’t, personally I would not purchase from a seller who ...

-- has more than 3300 items listed for sale at eBay, very few of which have anything to do with audio.  (His "store" states that "we mainly sell Japanese figures, apparel and daily goods");

-- lists this 40+ year old item without providing any indication of whether it has been tested and found to work;

-- has more than 2% negatives among his nearly 1000 feedback ratings in the past 12 months;

-- and is overseas, which might make returning it and obtaining a refund problematical should that be necessary. At the very least you would have to pay return shipping costs, per the stated terms.

Just my $0.02. Regards,

-- Al

I don’t know of any SUTs which provide a bypass function, although perhaps there are some.
The Denon au-320 most definitely has a straight through bypass option as I have told Elliot in previous threads.

I used mine to run a 0.24mv ZYX into input 1 running at the 1;10 setting and input 2 had a regular MM cart running through it on the bypass selection when in use.
Both worked perfectly well to my ears running into a Manley Chinook (amongst other stages) set at 47k and 60db gain.
And by that I mean QUIET!
I liked the flexibility of having two SUT in one AND a bypass option, gave a lot of options re cartridge choices.
Oh and I liked the prices of used AU-320 units!
So the 0.3mv should be perfectly fine at 1;10 into the mx phono.