Phono Preamp. With transformer or fully active

Hello Raul,

I actually posted that "story"on this site back in 2008.
 https://forum.audiogon.com/discussions/thoughts-on-cartridge-loading-with-a-sut

I have some more recent thoughts on the process and measured results at the link below. 

http://www.intactaudio.com/SUT%20design.html

dave

This Vintage Denon Integrated has one phono input and front switched internals for MM 2.5mv sensitivity and MC .125 mv sensitivity. 

https://www.ebay.com/itm/Vintage-Denon-PMA-750-Audio-80-Watt-Phono-Turntable-Stereo-Pre-Amplifier/174360505596?hash=item2898b22cfc:g:fGQAAOSwOI5e8Yd4

Very clean, you would need to get seller to ship if for far less money

Denon excerpt: Phono 20-100k, 0.2db

The MC/MM super equalizer is carried and the broadband characteristic of 20Hz-100kHz�}0.2dB is realized.
Composition consists of the NF form direct-current amplifier and CR form equalizing filter by newly developed low noise dual FET, and the first rank serves as dual FET differential amplification of the direct direct-current servo system.

https://audio-database.com/DENON-COLUMBIA/amp/pma-750-e.html

https://www.hifiengine.com/manual_library/denon/pma-750.shtml

Dear @intactaudio : I always say: " every day is a learning day " and througgh your last post confirm it. Really enligthing ! ! in a way " torture road " and sometimes controversial critical and important subject.

Thank's again.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Raul,

A number of years back I always found it odd that it seemed that there were two camps on loading of MC cartridges.  One camp insisted that 47KΩ was the proper number and changing it made little difference.  The other camp was fanatical down to the single Ω precision and it was always a fraction of the 47kΩ number.  It coincided that the 47kΩ crowd all used active gain stages and the fraction faction used SUT's.  If I assumed the 47k-ers to be correct and loading had little sonic effect, it seemed logical that the loaders might be effecting some other change than the sound of the cartridge and I started looking more closely at SUT behavior.  This has lead me to my current belief that when you load the secondary of the transformer you  change the sound of the transformer more than that of the cartridge.  

The wrinkle to both of the situations above shows up when you consider current injection behavior for MC cartridges where the load tries to become a dead short.  This one really bothered me until I read an article by Peter Moncrief in IAR#5 where he makes a convincing argument that loading a MC cartridge does not appreciably change the measured frequency response but it does have a marked effect on how much IM distortion is created.  What I found interesting about this concept involves the general sonic terms used for the for the reduction of IM distortion and two new warring factions were created in my head. 

The "Dampers" use the loading to explain the taming of a rising top end inherent to the MC topology.   A light load causes a rising response, and a heavy load causes the top end to roll off turning things into mud.  Somewhere in between the two one finds a safe middle ground and can live in peace.  A number of years back I split from this faction since the easily measured behavior of the SUT showed this behavior to a far greater extent than the measured cartridge behavior.

The "Loaders" lead by Moncrief simply state that the etched detail of an unloaded cartridge is an excess of IM distortion artifacts and when those artifacts are reduced, the seemingly dull sound is actually correct and the result of a series of system wide decisions previously made to offset the overly forward sound of the unloaded cartridge.

Everyone considers this all to be a black art and in reality it is simply a puzzle where all of the pieces fit together.  When you find two pieces that  seem to join but the pictures do not match you need to keep trying to see if you find a better fit.  Taking parts of truth from all of the factions above I am slowly coming up with a picture in my mind of how this all fits together in a predictable and repeatable manner.  Obviously I make SUT's so I'm going to explore those options.  You prefer an active stage so that is where your biases are.  Tubed vs. solid state are a couple of more of the warring factions.  This is where the subjective results come into play and ultimately we choose and follow the path that gives the most musical enjoyment.  That doesn't mean we shouldn't occasionally check our GPS when we start seeing the occasional polar bear.

dave

Dear @intactaudio : "  I make SUT's so I'm going to explore those options. You prefer an active stage so that is where your biases are. Tubed vs. solid state are a couple of more of the warring factions. This is where the subjective results come into play and ultimately we choose and follow the path that gives the most musical enjoyment.   "

Agree with. I use both alternatives.

Btw, after I seen a picture in your site I took in count that if I remember ( maybe I'm wrong. ) this gentleman @mikelavigne   posted that he listened or bougth ( ? ? . ) the silver wired SUTs and maybe you can confirm it or not because if I'm rigth then I remember too that he touted those SUTs:


http://www.intactaudio.com/images/Tran_images/canned%20SUT_SM.jpg

http://www.intactaudio.com/tran.html

Regards and enjoy the MUSIC NOT DISTOPRTIONS,
R.