SUT experience

Oh yea I mentioned earlier im using a project tube box MM phono pre at 60db gain into the line level input of the Mac.  I want a better standalone phono preamp after I know with certainty what features I want. The pro-next was an inexpensive way to test the waters. 

The preamp is a C47, not a 27.  It’s a modern unit

Nice to read that ET-100 SUT sounds good, I often recommend it based on it’s features: PASS for MM, 3 optional impedances/transformer windings, and 3 tonearm inputs front selectable, but never heard one.

Often available on hifishark, here’s one on eBay for $370. free shipping, 30 day returns

 

Like you, I was new to MC and SUT’s, I chose Fidelity Research FRT-4, similar features, usually cost more than the Entre, also 30 day return

 

SUT’s are Passive, no power needed, and actually are designed to deliver an unchanged but amplified signal by one of the SUT transformer’s windings to your MM Phono Stage. Each SUT winding has an x factor of amplification and resultant impedance load.

Your Ortofon SPU MC cartridge’s signal strength is low 0.2mv, it would benefit by an x factor about 20, i.e. boosted to around 4.0 mv.

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Something is unclear.

McIntosh C27 has only MM phono Inputs (2) (no MC capability), The MM input/the C27 phono stage perform the RIAA Equalization. Those MM Phono inputs are sensitive to minimum 2.0 mv. 10 times your cartridge’s signal strength (see pg 11)

 

SUTs Amplify, but do NOT modify the signal, the boosted signal still needs RIAA EQ.

Either a separate MC Phono Stage with RIAA Eq. (you did not mention),

OR, your C27’s MM Phono’s RIAA EQ. A separate Phono Stage optionally may/can perform RIAA EQ, in which case you use a LINE Level Input on a preamp/integrated.

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Is it possible you were running your MC cartridge’s 0.2 mv signal to the C27’s MM Phono EQ Input? If so, no wonder it did not sound great, and your Preamp’s Volume Control and Amp’s Volume would have to be near maximum.

IF you are now running the SUT’s output to the C27’s MM Phono Input, then the C27 is receiving enough signal strength to do it’s job well, it is doing the RIAA EQ, and the sound character of the C27 should be the same, but much improved by the 'strong enough' signal strength, volume controls down into the range where they are much quieter.

IF you are running your SUT’s output to one of the C27’s Line inputs, then RIAA is NOT happening, thus the signal to the amp would have it’s highs boosted and it’s bass cut, definitely wrong.

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btw, I had a McIntosh SS C28 Preamp, I DID NOT like it’s MM Phono Input’s sound, actually preferred the optional Phono EQ built into the Audio Technica AT120 TT, then into Line Level. Even a $14. Pyle MM Phono EQ to Line Level sounded better.

@adrianleewelch It is good to see the positive impression made from your making the experience of a SUT a realised encounter. I constantly share in these forums talking/reading is weak as a means to assess, direct experience "sitting in front off a item of interest", and witnessing it in use is the real foundation to satisfying decision making.

I'm not using the same Cart' as yours, but do use the same Brand, with same model Cart's, in use as rebuilt as a redesign and as the original design.

I have not experienced a Cart' in my system that did not become more attractive to my listening preferences without a SUT or Head Amp in use.

'More Attractive' is a personal mind set, my owned Phon's are more than capable of producing sound that is very very pleasing.   

👍

Tighter bass and extended highs were the immediate improvements but soundstage is huge now

Using an Ortofon SPU synergy at the 10 ohm setting through a Pro-ject tube box sounds a lot better through my line stage than my MC input ever sounded