SUT - electrical theory and practical experience

@drbond 

Basically a voltage amplifier will deliver voltage gain with whatever current is required to do the job.
Hence in a power amp, sometimes there is not enough current to maintain the voltage at the speaker

If there is not much voltage, but a bit of current then a current amplifier can be a good solution.

A current amplifier can later push that current across a resistor to compare the voltage… and drive a voltage amplifier in an output stage or RIAA circuit.

I think I mentioned earlier that this is using “the natural” ohms law.

and, in fact, the cartridge itself can push try and push the current across a resistor and use compare the voltage with a voltage amplifier.

The OP made it known that they are inquiring about a Specific usage of Ancillaries used in conjunction with a Cartridge and Phono-Pre-Amp'.

They made it known there were limits to their knowledge on the subject.

I can only assume the request to offer a description of whether a SQ is Improved or Degraded through the methodology is to be attained from a Subjective Evaluation and reports being offered from individuals who are familiar with methodology.

Receiving feedback from others who were or had optimised this method and who could offer a extended description as a result of the various permutations that can be produced will have shown, that certain permutations don't work for some and are rejected.

SUT's are usually met with the alternative being the Head Amp, and informing the OP of this as an option is an off-route diversion from the initial inquiry, but does have relevance.    

Another Older Thread has resurfaced with the SUT as the main Topic, and this will have proved to be an excellent read for the OP if they have visited the Thread. 

I hope the OP has been able to keep their eye on the prize and not get to bogged down in the noise that has been Trebuchet Launched into the discussion in an attempt to Siege the Castle.

Well done @pindac A trebuchet both looks, and acts, a lot like a tone arm.

(Or at least a tone that is not a great match to a cart.)

Seeing as it has a Rock Mounted at its furthest point of Cantilever, it is only really lacking a Bearing Assembly at the Anchoring Base.

Can one imagine the end of the days siege, when the oppositions meet down at the local Tavern. The Groups are slurping away and making bold claims about the who had the better day and end up having a bit of banter and head of to fight another day.

Remaining in the Corner is a member from an opposition, who is not so usual a type, who has intruded on a couple who are nothing to do with the conflict, and who were having a romantic moment.

The 'not so usual type' has entrapped the couple, so they could not vacate.    Where throughout the whole evening the couple have been exposed quite unwanted, to the 'not so usual type' incessantly going on about why their sides Trebuchet is better than the others. Where the designs are being drawn on Flagstones to show where theories are 'so called' proof of a design superiority.

That poor couple, I really feel for them when bombarded with such drivel from a very narrow minded, obsessive, 'not so usual type of individual'.     

Jumping forward a few Centuries, I'm glad that as diplomacy evolved, the Trebuchet developed into a Device for extracting embedded recorded data from a Disc.

The Heat of the Battlefield is still quite prevalent, in the P***ing Matchs, that are regularly encountered, where the endless drivel is constantly resurfacing and spieled out "My Twentieth Century version of a Trebuchet is better than Yours"  

Dear rauliregas

You ask "I think your PS is high gain active unit then why a SUT?"

Indeed. "Active" is just the beginning, regarding the Aesthetix Io, you could add dynamic, explosive when needed, and especially, pure. Pure tube sound all the way. If you like that kind of sound (I suggest we don't take that debate here).

There is only one caveat. You need a quite strong output cartridge. My Lyra Atlas works fine at 0.56 mV. If it goes lower, like below 0.30. e g the single layer low output version of the Atlas - you can most probably still get good sound, but there is a tube challenge. The four tubes in the uber-sensitive first gain stage of the Io need to be ULTRA QUIET. Not just ordinary good quiet. If not, you will get background tube noise. Maybe you don't hear much of it when playing music, but I don't like it anyway. AND if you like to feed the Io with the best tubes, you want the very best NOS in that position. And these can be hard to find, now.

I tested a SUT with the Io and did not like it - sounded good at first but then I noted that it subtracted from the purity, the sound became more hi-fi, for lack of a better word. But that was with a mid level SUT years ago and things could be different now.

I am happy with my Lyra Atlas, I think the synnergy with the Io is good, but it may be that I would have liked the low output version (Atlas SL) even more - with a SUT in between, to help it along. It seems that low output MCs is the main new direction of cart development, now.