Phono Preamp. With transformer or fully active

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.

@rauliruegas

right you are. i enjoyed my EMIA Ag 1:10 SUT so much, i purchased a second identical one for my other cartridge.

here is a picture: (scroll down the post to the last picture)
https://www.whatsbestforum.com/threads/etsuro-gold-mc-cartridge-in-house.29780/page-10#post-662650 .

my CS Port phono stage has one MC 63db gain input, and 2 40db gain, 47k ohms loaded inputs. so i’ve added those 2 SUT’s from Intact Audio and the performance is outstanding. there is a sexyness to these SUT’s superior to any high gain active phono pre i’ve heard.

added note; i worked for a couple of months with Dave Slagle with Intact Audio, tried a few different SUT’s, and ended up with the perfect one’s for my situation. Dave was awesome to work with and held my hand through the process. thank you Dave! you don't need to be a techie to use an SUT.

In order to add a bit to the road Mike went down his first audition was with two pair of identical 1:20's, one in silver and the other in copper.  Initially the silver was preferred and after a few weeks he found that the internal SUT's to the CS Port offered some benefits over the 1:20's he had in system.  A little bit of sleuthing turned up the distortion spec of 0.1% @ 0.76Vrms output.  Working this number backwards from the 40dB of gain this translates to 7.6mV of input.  The Etsuro Gold has 0.56mV of output and fed to a 1:20 that will be slightly above the 7.6mV level.  It turns out that the CS Ports internal SUT had 3dB less gain which using simple math put the output right at that published distortion number which is why I suggested that mike try a 1:10.  I sent him a copper 1:10 for his 4Ω Etsuro and things improved over the internal SUT.  Replacing the copper with silver was the icing on the cake that he is currently consuming.  

I think the important thing to note about this is the high frequency overload characteristics of phono playback is typically not pretty.  At high frequencies many phono stages seem to have a more abrupt transition into distortion where the higher order artifacts show up and quickly dominate.  This high order high frequency distortion only happens at dynamic peaks nearing the highest possible groove velocities.  Holman notes a worst case 105cm/sec peak @ 7Khz on  Woody Herman Verve V-5885 and that represents 26dB above the standard 5cm/sec velocity referenced to 1kHz.  Granted the 7kHz signal receives 10.7dB less gain but that still leaves a 15dB dynamic peak above the 1kHz baseline.  It is these periodic events tickling the abrupt onset of distortion that I find gives a "something is not right but I'm not sure what it is" type of feeling.  It is the periodic occurrence at dynamic peaks that make it so elusive.   The trend as of late is for MC carts with 6dB or more output than their predecessors which simply translates to a 6dB loss of high frequency dynamic headroom when considering a MC stage built with a 0.2mV SPU in mind.  10 years ago a 1:10 was an anomaly and today with MC outputs in the 0.5mV to 1mV range it is slowly becoming the norm.

dave 

Dear @intactaudio :  From some years now LOMC cartridge designs comes with higher output levels than in the past.

That healthy higher output makes a more easy way for phono stages to handle LOMC designs, especially tube electronics but that healthy output comes with a trade-off in the overall cartridge quality performance levels.

If that Etsuro Gold instead of 0.56mv came with say 0.15mv I have no doubt that @mikelavigne  will be even more happy that with his already great Etsuro samples quality performance.

Problem is that 0.15mv can be a problem even for SS phono stages. Nothing is perfect but normally lower output mv means less wire in its coils with more powerful magnets as neodymium ones.

Lyra is a good example about when JC started with his Atlas/Etna models and latter on he presented the new same models in low output fashion and owners and reviewers gone with a smaLL PREFERENCE FOR THE LOWER OUTPUT MODELS.

I remember what happened in the past with some of the LOMC cartridges I owned, example: AT MC 1000 that was marketed along its dedicated SUT AT 1000T for its low 0.1mv output or the Ortofon MC2000 that appeared along its dedicated SUT T-2000 for its very low output of 0.05mv and the same was with Audio Note design. 
All those cartridges came with very high quality level performance but not easy to handle for phono stages, certainly not tubes designs.

Latter on I remember my first Colibri with a not so lower but certainly not something approaching the Etsuro output, this Colibri had 0.21mv and performed excellent in quality kind of sound. Latter I bougth two other Colibri samples but VDH only offered with higher output and I have to say that nothing like the " original " 0.21mv polymer cartridge body.

Anyway, good that both of you are satisfied with.

R.