SUT Advice - Which Ones Are The Best?

@itsjustme   Excellent points!

Not to be difficult, but to get everyone on board with the simple facts rather than vague goals of "simple signal path": 


how does replacing many active components with one passive component, that in fact performs an impedance transformation rather than delivering pure voltage again, "simplify" the signal path???  In my view it vastly complicates it.

if you think an MC RIAA stage is a single stage, you are generally mistaken. It's a bunch of gain stages -and from MC to line in, typically three, with each having multiple active devices. Both the aggregate gain and number of stages can be reduced by placing the RIAA filters in the feedback loop of quite a hgih gain and complex stage, but now we have introduced a complex, global feedback loop which i personally find undesireable.


vs ONE passive device.  yea, it has complications too, but its much simpler.

I think in a perfect world @rauliruegas is correct...the goal is to simplify the signal path and not add a SUT if at all possible. The problem is that unless you're using a top-tier SUT there is a good chance that a quality SUT combined with the MM-stage may outperform the onboard MC stage.  I have seen this in many of my phono stages but I've never owned a truly high-end phono.  A/B comparisons in my gear history shows improvements to SQ when using a SUT.

There is no way that your Kleos can in any way sounds with better quality level through a SUT in your system when you own a very good phono preamp that handled any LOMC cartridge.

When you add a SUT to your specific system you are adding an additional stage with severe limitations in frequency range against your KTE unit and other issues down there but additional you need to use an IC cable with additional connectors at both ends of the cable from where the cartridge signal must travel through and in all that " travel " the signal is degrading and developing additional ( every kind. ) distortions: you are contaminating that beloved MUSIC signal.

Well, since I’m in the middle of refining a MC/MM (jumper it to your liking) RIAA gain stage design I’ll bite. You think a gain stage, amplifying a 0.05-0.5mV signal by another 10-20X has no distortion? Do you realize how lower the power supply noise must be? Or how high the PSRR must be to make that irrelevant (which takes some doing)?

I will take two wires and a rally, really good transformer any day. Now you may ask "so why are you designing a low noise gain stage?" - answer: simplicity and cost. A good SUT (hate that acronym) is quite costly and heavy and somewhat complicated for many reasons that are peppered throughout this discussion.

I’m no necessarily arguing for a SUT, but i’m also not convinced that the active stage is a no brainer. Mitch Cotter agreed, and he was no mathematical slouch.
G

@rauliruegas,

On this one I respectfully disagree:

I run a Zyx Universe through a Zyx Artisan stage. When inserting an Altec TBB-103 based SUT that Bob made it gives a substantial leap in performance: faster, more soundstage and definition of instruments. Ruling out SUTs as a way of improving vinyl playback contradicts what many cartridge designers are saying.

Dear @snackeyp  : In good shape: why do you want to degrade the valuable and sensitive cartridge signal  ?

There is no way that your Kleos can in any way sounds with better quality level through a SUT in your system when you own a very good phono preamp that handled any LOMC cartridge.

When you add a SUT to your specific system you are adding an additional stage with severe limitations in frequency range against your KTE unit and other issues down there but additional you need to use an IC cable with additional connectors at both ends of the cable from where the cartridge signal must travel through and in all that " travel "  the signal is degrading and developing additional ( every kind. ) distortions: you are contaminating that beloved MUSIC signal.

Yes, through the SUT will sounds different and probably you can like it but what you like it is a true inferior quality level.

The SUT " party " of other gentlemans here is with all respect a party where you don't need to participate, their system specific needs are different from yours.

Anyway you can try and can participate too in the " party ". Is your call.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

I also bought a Silk Audio SUT from Thailand.  They were very easy to work with in assembling a unit for me.  (They also sell the transformers separately.)  Mine looks and sounds great!

I run a Bob's Devices Cinemag Sky40 with my SPU's and an Auditorium A23 with my DL-103's

70s era Mitch Cotter strapable transformer like i have  LOL?

(but am not presently using since I'm in the hell of trouble shooting a configurable FET/BJT cost effective module- noise gremlins lurk everywhere when the effective gain from the needle to the speaker is 20,000X)

I recently picked up a SUT from Ned Clayton for my Denon 103R. Cinemag 3440AH transformers with four winding ratios - 1:9, 1:12, 1:18 and 1:36. Quality product and was reasonable at under $400. He has an eBay store where you can browse what is for sale or email him directly. 

I currently run the Bob’s Devices 1:20/1:40 with the Denon 103R and a Hana Mono SL; an Icon Audio 1:10 with the Hana ML; and the Miyajima ETR Mono with Zero’s and Infinity. The Miyajima does have a switch to select impedence in addition to primarily and secondary coil taps. Between the three I would call Bobs Devices the most transparent, the Icon Audio the most lush, and the Miyajima the most compete. If the Miyajima Stereo fits, that’s where I would go. 

I only have limited experience with SUT's, auditioned an Ortofon SUT once but unfortunately, there was a gain mismatch with my then AT33 PTGii cart so I wasn't convinced that adding one would be an advantage. Then, a very experienced audio buddy of mine told me about http://www.acoustic-dimension.com/silk-audio/silk-audio-supermalloy-mc-220A-step-up-transformer--pag...

Made in Thailand, the few reviews I chanced across online were encouraging, pricing also made it attractive. Bought it blind and based only on that one recommendation and it turned out to be a great addition to my analog chain. I've compared the Silk SUT with the MC section of my phono pre (which uses permalloy transformers) many times and hands down using a SUT into the MM stage of phono smokes it every single time.

w that much gain you do not  unless you like the sound of miles of wire…only slight hyperbole in trade for what is likely a FET input.

one popular trade is a lower gain all tube combined w SUT.

May be a stupid question but if you have a phone stage which pro ides 65db and has multiple options for loading ohms as well as settings for both MC and MM why would you need a SUT? I have Manley Chinook phono pre amp and am curious?

Thank you

Bobs gives you the best sound. I have compared many more expensive SUT but the Bobs just sounds better.

@jasonbourne52 gives good advice in terms of trying different devices to dip your toes in.  I got a Denon AU-320 for around $200 -- and it has brought phenomenal performance-for-$ results.  And like someone else mentioned, these items don't particularly age or wear out (yes yes, some exceptions like oxidization can happen).

You may well end up with one of the true high end and exceptional SUTs... but won't it be fun to begin with a lower-risk option such as a used SUT for just $200-250, and then see where the journey takes you?  And if you are looking at $2k+ SUTs later on, that's really just a rounding error in total cost and will make a fun comparison  :)

auditorium23 make a very highly rated SUT for low output MCs

Cinemag publish that as i recall, unless tgere is a hidden R lurking….

JCarr, thank you for the erudite post. For most of us, the needed gain is easily estimated, and the internal impedance of the cartridge is available from the maker, but I know of no instance where the primary inductance of the SUT is accessible to the end user. How does one acquire that data point?

Lots of great responses.  I really appreciate it!
Peter

not snark, but in my experience more than a few audiophiles don't much care about phase. I do.

nice to have Jonathan weigh in.

@pindac there is a lot of wisdom in your post re; system matching and synergy 

best to all, excellent thread

I got my 1st MC cartridge not long ago, and after research and advice here, went with this one:

https://www.ebay.com/itm/164633673789?hash=item2654ee803d:g:WLUAAOSwcnVf-M6S

they are getting expensive, and harder to find

a. PASS lets you use it for a MM or MC High Output thru it, bypassing the transformer

b. 3 inputs, front selectable, then off to a single MM Input.

c. 4 optional x-factors/impedance loads, for my first, and future MC cartridges
(front switchable, not rear or internal dip switch changes).
...........................................................

This model, FRT-5, has 3 inputs, PASS, and it’s Transformer is designed for MC cartridges in a range of 3 to 10 ohms

https://www.ebay.com/itm/334079978776?hash=item4dc8b7ed18:g:iNcAAOSwPNpg8nR7

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

Entre ET-100; 3 inputs, PASS, 3 Optional Loads, front switch

https://www.ebay.com/itm/393529405956?_trkparms=ispr%3D1&hash=item5ba02e3204:g:XHcAAOSwHmlhJMuD&...

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

Denon, 2 inputs, PASS, 2 optional loads

https://www.ebay.com/itm/393583791431?hash=item5ba36c0d47:g:jrAAAOSwug5hR7ZR

One of the nice things about SUT's is that they are passive devices and hardly subject to aging under normal use. And the 'technology' hasn't changed much, if at all. This means you can buy used without hardly any risk at all.

There are two 'big' choices you have to make:
- copper or silver wire for the transformers. Silver is obviously more expensive, but not necessarily better (very dependent on the cartridge)
- a dedicated unit for a specific impedance range or one with a selector switch to accomodate a wider variety of cartridges (usually choice between low impedance (typically 3-6 ohm) and high impedance (20-30). People usually prefer dedicated units, because the selectability involves extra switching.

There are many great ones out there, but a good choice for copper wired SUT is Entré ET-200 for 2-10 ohms (3,5 ohms ideal) and 30dB gain, designed by Matsudaira of My Sonic Lab. This is not a rare unit and regularly for sale around $600-700. The current My Sonic Lab SUT will not be much different except for the price.
A good choice for silver wired SUT is the Ortofon series for their '000' series MC's, the T-2000, 3000, 5000 and 7500. They all have the same specs (impedance range 3-6 ohms, 30dB gain), except T-2000 which has even higher gain to accomodate the ultra low output MC-2000. These nits can be found between $1000-1500 and are definitely worth it when compared to the 'adventurous' pricing of silver wired SUT's made today.

I forgot to add that I have a fifth SUT on hand: a pair of Sony ST10’s that are the smallest I’ve ever seen. They are square cross-section, about two inches long, an RCA plug at each end - one male and one female. They are each a single channel and plug directly into a phono stage’s RCA jacks. Amplification factor of 10X. No ground wires. Rather neat! Bought from an eBay seller for $175.

@jcarr thanks for the detailed response. When you say low impedance what number are you looking for?

It is sometimes said that an SUT should be matched to the cartridge (or the other way around).
The reason typically given is the need to have an appropriate amount of SUT gain to bring the cartridge's output up to a level that is comfortable for the chosen phono stage.

However, there is another less-known but equally important reason, which is that the low frequency bandwidth and phase response of the SUT depend on both the inductance of the SUT's primary windings, and the net impedance that the primary windings will see, according to the following formula:
f = Z/(2*Pi*L)
where f is the frequency where the amplitude is 3dB down compared to higher frequencies,
L (in henries) is the inductance of the SUT's primary windings
Z (in ohms) is the net impedance

The inductance of the SUT's primary windings should be measured with the secondary windings left open. (Note that a completed SUT may contain internal load resistors across the secondary windings, therefore it is risky to assume that simply because the SUT is not connected to a phono stage, the secondary windings are truly open.)

"Net impedance" in this particular situation means the phono cartridge's source (self) impedance, in parallel with the impedance that is reflected back from the SUT's secondary windings (when connected to a suitable phono stage). Usually the net impedance will be dominated by the cartridge's source impedance.

The mathematical formula tells us that in order to improve the low-frequency capabilities our options are to lower the source impedance (choose a cartridge with less self-impedance), increase the primary inductance of the SUT (increase the number of transformer windings, increase the dimensions of the transformer core, or use a higher-permeability material for the transformer core).}

In a nutshell, the larger the self-impedance of a cartridge, the more primary inductance will be required from the transformer in order to keep the same low-frequency extension or phase response.

Conversely, if the cartridge has small self-impedance, less primary inductance will be needed for sufficient low-frequency extension or phase response.

Although the target frequency for "f" in the formula above could conceivably be set to the lowest frequency expected to be reproduced, if good phase linearity is likewise a goal, this will require a considerably lower target frequency.

Caveat: although good low-frequency performance from a transformer requires sufficient primary inductance, since high inductance (in the form of more turns, or more wire length per turn, or higher-permeability core materials) tends to pose problems for high-frequency performance, single-mindedly selecting a transformer with as much primary inductance as possible, isn't recommended either.

Summary: When choosing an SUT, be sure that the gain is appropriate for the output level your phono cartridge.
Also be sure that the SUT's primary inductance is suitable for the coil impedance of your cartridge.
When connecting a SUT and phono stage together, try to choose as low-capacitance cable as possible, using as short lengths as possible.
Generally SUTs work better with low-impedance cartridges.

I use Hashimoto HM-3 and Cinemag 1251.
I am quite familiar with other SUT Brands and Head Amp's used within my own system and other owned systems. 
All my experiences I have taken part in will allow for me to detect that a  SUT will add a richness to a replay. Even though this trait is difficult to detect on certain Brands of SUT,  it is a noticeable trait when a SUT is A/B compared to a Head Amp'.
I have to date not heard a SUT that has a comparable transparency that a Head Amp' can produce.
In my system I am comfortable with each presentation and at present feel that the Cinemag 1251 has the Interface and Presentation that is most suited to my preference, it has a design that enables it to project the Upper Mid's and produce a very controlled Tight Bass Note.    

I have four SUT’s: Bellari, Denon and two custom-builds using vintage mic transformers. Presently one of the custom jobs is paired with the Coral 777 Sleeping Beauty lomc on the FR29 arm/Ariston RD11 TT. All these SUT’s have there own "flavor" - they all sound "good"! The Bellari was bought new and was the most expensive. The Denon is in use with the Denon 103R on the Pioneer PLX1000 TT. Previously it was used with the Bellari. The other three came from eBay sellers and averaged ~$200 each. So no need to spend a lot of money! I like to have a variety to play with different lomc cartridges!

Cinemag, then Bob but personally I prefer the FET in the front end of my Herron to deal w my Lyra.

I have not heard the Zesto, but i have heard the preamp and they have ears and build great sounding gear….

For adjustability the Zesto Andros Allasso is among the most versatile, but you pay over $2,500 for that adjustability of gain and loadings. I have this SUT in my main system and it’s a nice unit.

For my second system I bought a used Rothwell MCX for $270 to pair with a Hana SL (0.5mv) and it's truly a great pairing it is. The Rothwell uses a Lundahl transformer and provides 20dB gain which is perfect for me. There are so many carts on the market (including Kleos) that are about 0.5mv and like ~400ohm loading that I sometimes wonder if I purchased too much flexibility with the Zesto.

Of the Bob’s Device I think the SKY20 is the one I’d get with it’s 1:10 and 1:20 configuration which would fit most of my foreseeable needs.