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Entre' ET-100 SUT

Posted this on Vinyl Asylum.  Thought I'd try here too.

 

Hi all,

I've been looking in to SUTs and my word it is remarkable how varied opinions are on just how best to think about loading and voltage matching.

In light of that, and in light of the fact that I have a three armed system and a variety of LOMC cartridges (nothing fancy) with a variety of output voltages and impedances (5-40 ohms, including Denon DL-103r (14ohm, 2.5mv) and DL-301II (33 ohm, .4mv)), it seems a good way to go is with an SUT that has multiple inputs and variable settings.

One such is the Denon AU-320 (or 340) but that gives only 3 and 40 ohm options (and pass through). I had a Denon AU-300 before, and quite liked it.

But another option is the Entre' ET-100, which has three(!) inputs and three settings. There seem to be two versions (3, 10, and 40 ohm; 3, 20, and 40 ohm) There's a slew of them available used from mostly Japanese sellers.

But the thing is, I can find almost nothing about them online -- no reviews, no complete specs (step up rations for the various settings), no discussions. Without knowing the actual step up ratios, I wouldn't know whether to get the one with the 10 ohm setting or the one with the 20 ohm setting, if I were to order one.

So, anyone familiar with these things? What can you tell me or where can you send me?

rnm4
elliottbnewcombjr
5,363 posts
 

It is confusing, I learned from others here first, then subsequent research.

I also have a TT with 3 Tonearms, multiple cartridges

 

I often see the ET-100 listed for sale, and have not crossed path with detailed info. You might ask seller’s if they have a spec sheet they could take a photo of.

I chose a Fidelity Research FRT-4, very similar to the ET-100, usually costs a bit more. It is totally quiet.

It has 3 front selectable inputs, PASS for MM, and 4 settings for MC Low Outputs needing signal boost:

3/10/30/100 ohms. Respective X Factors: 35.84/20.68/18.27/10.55

others are listed, this one looks darn good

 

FRT-4 has a captive phono cable out, sounds great, sometimes I think about having Steve or Ray at VAS change it to RCA out, to use a ’better’ or shorter cable, but that’s just because I’ve run out of things to change, no need.

...............................................

My notes from original research list, a few I never investigated

Andros, Allasso: 4 low x factors: 4/6/8/12: (multiple arm inputs?)

EAR MC4: 4 x factors 10/18/24/30 (multiple arm inputs?)

EAR MC3: 3 x factors 10/20/30 (multiple arm inputs?)

a scribble ’cinemac 36,18,12,9 ????

rnm4 OP
308 posts
 

Thanks, Elliot (I assume),

 

I saw the FR4, but was hoping to spend less.  A possibility, though.

 

So just to confirm, by "X factor" you the number times which the cartridge voltage output is multiplied through that setting?

 

Richard

rnm4 OP
308 posts
 

"you mean", I mean.

elliottbnewcombjr
5,363 posts
 

Elliott is correct, and yes, x factor x cartridge signal strength = resultant signal strength out of the SUT into the MM phono stage (allow for a bit of loss).

use X factor squared to calculate what ’resultant’ impedance that will be shown to the phono stage:

say x factor 20 i.e. xfsq 400.

typical phono input 47k (not all).

47,000 divided by xfsq 400: impedance ’shown’ out of the SUT to the phono stage will be 117.5 ohms

guidance for ’shown’ impedance is cartridge impedance x 10.

my at33ptg?II is .3mv and 10 ohms impedance. So, I’m looking for enough/not too much signal strength and resultant ’shown’ impedance of around 100 or higher.

FRT-4’s 10 ohm input is x factor 20.68. that gives me signal strength of 6.3mv (remember to deduct some loss) and ’shown’ impedance of 110. Nice combo!

Some cartridges signal strength and impedance are difficult, a phono stage with individual gain settings and individual impedance settings may be needed.

 

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