Help making right SUT choice for LOMC cart

[rbc3]

I have a Dynavector 20x2l cart that's .3mV with a recommended load of 30 ohms or greater.  The two best choices are a 1:20 turn SUT or a 1:30 turn SUT.  The 1:30 SUT is better in dropping the load of the Reduction from 47.5K ohms down to about 53 ohms to the cart, but the voltage to the Reduction will be over 9mV, above the sweet spot of 5mV.  However the 1:20 SUT will deliver 6mV to the Reduction, closer to the sweet spot.  But the impedance load on the cart will be higher, around 119 ohms.

I prefer the 1:30 SUT for better impedance load matching on the cart, but I'm not sure if 9mV to 9.5mV is too much for the Reduction.  Please advise.  Also how about the Eros?  Will it handle the higher voltage better than the Reduction?

Thanks in advance,
Robert

 

[Paul Birkeland]

The 1:20 is the better option.  It's quite easy to lower the input impedance of the Eros if you need to adjust the loading.

-PB

 

[Doc B]

Recommended load is 30 ohms or greater. Why not try it and see how it sounds before deciding what the load should be? You can always adjust it.

 

[Paul Joppa]

Best bet is to parallel a suitable resistor across the cartridge or SUT primary. This will have minimal effect on the transformer response. And it's easily reversible for comparison listening!

 

[rbc3]

OK, so it seems like the recommendation is to go with the 1:20 SUT that hits closer to the target voltage and then play around with resistors in parallel to the SUT primary to find the optimal load for the cart.  And I hear you Doc.  The cart specs do state 30 ohms or greater, so 100(ish) ohms might be a perfectly suitable load on the cart.  I've read posts by plenty of people who load the 20x2l with 100 ohms on transistor based MC phono preamps and like what they're getting out of the cart.

Now I have to decide whether or not I go for a Reduction + Integration at 40db gain or go for Eros at 50 db gain.  I suppose you guys are going to recommend the Eros + BeePree is a better match with the Mainline that I just ordered.  Or do I even need a preamp since the Mainline has two inputs and all I'm going to run in to it is a phono pre and a DAC?

-Robert

 

[Paul Birkeland]

The Eros will pair with the Mainline without a line preamp, you won't need it.

The Eros and Mainline are of similar design quality and complication, and the extra gain makes for a lower noise floor that is pretty handy when you're using a dedicated headphone rig.