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Topic: The TX-103 optimization kits...

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Posted by Antonio J. on 12-30-2004

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I'm a phono moron, but having had several phono preamps, I think I can understand what finds Romy right in the EAR 834P, which I love. I'm not as skilled and crazy as to try to make all the Thorsten mods in it by myself, but I've tried some tube swapping and I find the sound of this thing quite good with some Mullard and Telefunken tubes.

I have been searching info about the ET SU-1 and it seems impossible to find any of those step-ups to get rid of the one into the 834. Are there other alternatives, which not being as rich sounding as the SU-1, can be an interesting step over the 834's built in one? Perhaps the S&B or the Bent's? or perhaps someone can point me to somewhere I can get an ET....

Regards.


Posted by Wellfed on 12-30-2004
Bob Graham of Graham Engineering can provide you with a silver wire transformer that sounds great to my ears.  More accurately, I don't hear it detracting from my enjoyment.  I use mine in conjunction with his silver wired phono cartridge so there is probably system synergy involved.  I am unable to tell you how this stacks up against the ET unit.

Posted by Brian Clark on 12-30-2004

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 Antonio J. wrote:
Are there other alternatives, which not being as rich sounding as the SU-1, can be an interesting step over the 834's built in one? Perhaps the S&B or the Bent's?


The Bents ARE S&Bs Antonio but custom wound using John Chapman's supplied wire. I have a pair of S&B TX103s which I will press into service sometime in the not too distant future. Everyone I know here in the UK who has tried them has been impressed - no, make that VERY impressed.

Brian.

Posted by Chirag on 12-30-2004

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Hi guys,

these do seem quite interesting, but much of the written hoopla i've seen is coming from some of the less interesting characters on another BBS.

from a fairly capable system i heard last week, the S&B's set for maximum gain seemed to work quite well with a big old technics table, old SME and some cart i don't remember.  the system did have a massive hole in percieved quantity/quality above 3k so i cannot be completely confident in trying the S&B's in my own setup, but they definitely showed serious promise.

has anyone tried the the big Jensen MC's? its a name i don't see come up too often, but they don't impress me as incompetent.  a nice 27db gain, 75 ohm Jensen 347 could show promise.

best,
hirag


Posted by Romy the Cat on 12-30-2004

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Antonio, you might information about Expressive Technologies transformer at here:

http://www.goodsoundclub.com/Site_images/SU-1.jpg.

I have linked it form ‘My Playback’ section, also in there should be link to a Stereophile article about SU-1 from beginning of 90s. It was in a king of customary-foolish article where a typically idiotic-reviewer (I do not remember who was it) plagued the ET-1 transformer into a low impedance input of the Curl’s Blowtorch and then he complained that when violins went to crescendos his wife cactuses lost their thorns.

The ET went out of business and I do not think you will fish those transformers, although the accidents are always possible. I know there is a guy in UK who has one ET-1 sale but he wants somewhere around 7500 pounds… quite aggressive price I think.  I sold my ET-1 a few months ago and I do not know where to get more. (BTW, talking about the irony: the dirt that runs Audiogon banned me from there because he believed that I should not sell a transformer for more money than the value of his entire trailer. What a cheap profound idiot!!!)

I would like no one subscribe a notion that it is necessary to search for the ET-1 (or any other “better” component). ET magnetics were fine but it was good if you are a specifically interested in that “goodness”. Also, it is very important to understand that this specific interest in the “goodness” has nothing to do with the actual benefits a person can get out audio. Yes. ET-1 does some unique things to sound but after you have it on your shelf then you forget about it and still listening the recording instead of the ET-1’s benefits. What I am trying to say that all those ET-1 advantages (or the advantages of any other “superior” audio components) has meaning only when we do our audio-talk. For music listening all those audio-talks are very much irrelevant.

Alternatives? Many people recently use S&B. The 103S are les interesting then ET-1 (the S&B unfortunately does just gain, nothing else) but for the money S&B do OK. In fact, I feel that S&B better then many other transformers. For instance the S&B is way better then the Graham’s transformer, although when I had Grahams it was a preproduction prototype and perhaps they did better later on … Yet, although the S&B is OK transformer but I still feel that the hype around S&B is blown primary due to low requirements and low demands of the transformer users…

Rgs,
Romy


Posted by Antonio J. on 12-31-2004

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Thank you very much for your responses guys. I'll see if I can get a S&B to try with the EAR and listen how the music benefits or not from it.

Romy: I understand things in the same way you do, I mean that I mainly listen to the music, you may remember when I had a serious disappointment with my system's sound, but that was fixed by the Bidat. Now I try tweaks and upgrades, but I'm not looking for "more" I just pay attention to the music and when I listen I can forget about "sonics", but this doesn't "fix" the fact that I know that my system should do some things different to really sound like I want it to sound. Perfect sound? I don't think so, but it would be "the sound to forget about sound". The matter here is that one cannot know for advanced if one tweak or upgrade will take you into the desired direction (there's not a single person out there that can really know it because each of us has it's own taste, expectations and needs to be fulfilled to get true musical enjoyment), thus some testing is required, but there are too many brands, models, and devices out there that having some clues about what is worth trying is very very welcome.

Regards and Happy New Year to all you,

Antonio

PS: I have e-mailed S&B and I received an answer from Jonathan Billington, adressing me to this site: http://www.mfaudio.co.uk/ They build the SUT using their transformer as Bent does. Do you know them?


Posted by Brian Clark on 01-05-2005

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MF Audio is the consumer product offshoot of S&B

Brian.

Posted by Antonio J. on 01-05-2005

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MFA e-mailed me aknowledging that I was perhaps going to try the DIY way getting a "raw" transformer from S&B and offered me assistance. The "problem" is that their unit with a gain selector and load selector is way too expensive for my budget (1500 UKP), while the raw transformers are about 250 euros each. The Bent Audio alternative looks interesting, but I don't know if the copper transformer or the silver one would be a better choice for what I want to get from my vinyl rig. John Chapman is very helpful and said the silver one is thinner sounding and the copper one is fuller, but what I want to improve by getting a stepup is not exactly changing the frequency response, but having a clearer overall response, more spatial deffinition while preserving the coherence and "wholeness" the EAR already has. Something that shows in a clearer way the integrity of the harmonics linked to the source of sound, apart from the other sources in the stage. I'm concerned for the silver transformers being too analytical spoiling the sense of coherence. Any experiences?

Regards.

Posted by Romy the Cat on 01-05-2005

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Antonio, I never understood this concept of “gain selector”. If I remember correctly S&B had 10, 20 25 db options via re-wiring of the primary coil. It is not complicated to place primary in some kind of rotary 3-position switch but it would be completely unnecessary. Presumably all those aftermarket S&B resellers try to convince buyers that by they would “have a flexibility to select a gain whatever they wish” but I find that it is quite a bogus benefit. Fist: it is VERY difficult to fine a switch that would commutate 0.3mV signal without any sonic degradations (at list I was not able to find any). Second: people need one permanent gain for one given cartridge/phonocorrector and no one doing the switching after a necessary gain was found (people who use multiple needles and multiple arms usually have multiple phonocorrectors). Third: by flipping the primary coils and changing the gain we change loading impedance and therefore we observe not only the gain effect but also the variations of cartridge’s coil damping. Therefore, if you’re willing to use S&B then get them raw and considering that the cable between the transformer and phonostage is the most critical of all then just mount those S&B directly to the binding posts of your phonocorrector. The S&B despite of very simple mu-metal can are quit quiet and it can easily work in this application. I would go for 20-25db and then just tune the loading resistor. To have those “luxury” options that Bent Audio and few other offers I find not only unnecessary but also “bad for sound”.

The Cat

Posted by Brian Clark on 01-05-2005

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Yes, keep it simple.
Products made for sale in showrooms are loaded with bells and whistles to impress and dazzle the gullible. More stuff for the salesperson to browbeat customers with.
Also manufacturers like to throw their net wide to maximize their "catch".

Brian.

Posted by Antonio J. on 01-05-2005

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I see, so I'd better get plain copper trannies from S&B directly, and plug into the EAR's inputs. I'll ask you how to set up loading with some resistors I guess. I said I'm a moron ;-)

Regards.

Posted by Thorsten on 01-24-2005
Hi Roman,

 Romy the Cat wrote:
the S&B unfortunately does just gain, nothing else) but for the money S&B do OK.


Then it does exactly what is asked of it, I asked JB to design it for me PERSONALLY as a "wire with gain". I have been on previous occasions been unconvinced of many stepup transformers, be they sowter, amplimo, EAR or jensen.

The only ones I got to like where old Mike stepups from Neve Mixing Desks and some ancient and I mean ultra-ancient Ribbon Mike stepups pulled from an old grampian console. Both of these where of course virtually single pieces and even they retained some colorations.

The TX-103 has come very close to a "wire with gain", which is more than I can say about most other passive or active steups. Not everyone wants or needs a wire with gain, well as the BBC commented, other suppliers exist.... ;-)

Ciao T

Posted by Thorsten on 01-24-2005

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 Antonio J. wrote:
MFA e-mailed me aknowledging that I was perhaps going to try the DIY way getting a "raw" transformer from S&B and offered me assistance. The "problem" is that their unit with a gain selector and load selector is way too expensive for my budget (1500 UKP), while the raw transformers are about 250 euros each.


The fully build stepup is priced for retail distribution in your local shop. As such it has dealer and distributor profit margins build and is a product build with general compatibility in mind etc. For anyone who can solder well and who does not mind the absence of a "finished product" finish the raw transformers are available too. You might be surprised to know that MF-Audio actually does make proportionally to the work required makes about the same income as S&B does for a TX-103 and JB is not getting rich from it.

One might also consider that the nearest competitor, namely the EAR MC3 Stepup costs more than 1/2 of the MF Audio unit and offers less adjustability, the sound has been commented on elsewhere.

 Romy the Cat wrote:
Antonio, I never understood this concept of “gain selector”.


It is not a "gain selector" as much as it is a selector to match the cartridge source impedance. Very low impedance cartridges (many modern MC's) should be used on the highest stepup setting (1:20/26db), as that matches the transformers operation correctly. On the other hand, MC's like the Denon DL-103 do not sound under such conditions as their internal impedance is much higher, so they should be connected ideally with the lowest stepup (1:5/14db) as that matches the impedances best.

Failure to match impedances well will invariably colour the sound, I would say worsen it.

 Romy the Cat wrote:
If I remember correctly S&B had 10, 20 25 db options via re-wiring of the primary coil. It is not complicated to place primary in some kind of rotary 3-position switch but it would be completely unnecessary.

 
I disagree. In order to be able to get the best out of an expensive cartridge and stepup one MUST have the ability to both match the input connection of the transformer and to apply varying loads.

The normal approach to handeling primary impedance matching is to use multiple taps on the primary and to simply leave the unused part of the primary unconnected. That usually impacts on the sound and not in a positive way.

Therefore the MF Audio Stepup (which you might call my design if you so wish) has a Selector for the input connections and for loads down to the nominal 10K secondary impedance.

 Romy the Cat wrote:
Presumably all those aftermarket S&B resellers try to convince buyers that by they would “have a flexibility to select a gain whatever they wish” but I find that it is quite a bogus benefit.


No, the point is actually that unless you wish to actually design a transformer specifically for a given cartridge you must be able to select the correct primary impedance OR you must accept sonic losses, which BTW are by far greater than the ones caused by the switch.

 Romy the Cat wrote:
Fist: it is VERY difficult to fine a switch that would commutate 0.3mV signal without any sonic degradations (at list I was not able to find any).

 
Maybe. The switch that is used proved itself sufficiently transparent that there was in several systems, including much more elaborate ones than my own, no material degradation between a hardwired and a switched version.

 Romy the Cat wrote:
Second: people need one permanent gain for one given cartridge/phonocorrector and no one doing the switching after a necessary gain was found (people who use multiple needles and multiple arms usually have multiple phonocorrectors).

 
Yes, you need only one primary impedance and one gain and one load for a given combination. However, if you alter this combination you need to change. I felt giving users the ability to do this change direct and for themselves is of value.

 Romy the Cat wrote:
Therefore, if you’re willing to use S&B then get them raw and considering that the cable between the transformer and phonostage is the most critical of all then just mount those S&B directly to the binding posts of your phonocorrector. The S&B despite of very simple mu-metal can are quit quiet and it can easily work in this application.

 
I agree. However there are enough people who refuse even to consider something where they may need to take the lid off in order to adjust something.

 Romy the Cat wrote:
I would go for 20-25db and then just tune the loading resistor.


I would choose a primary connection that is actually apropriate to the internal impedance of the cartridge, eg. for Cartridges in the 3-10R region 1:20, for those in the 10-30R region 1:10 and for pickups above 30R 1:5.

 Romy the Cat wrote:
To have those “luxury” options that Bent Audio and few other offers I find not only unnecessary but also “bad for sound”.


Sorry, but in order to make that call you would have had to have compared an MF-Audio Stepup to a hardwired 103, which you have not done. We have done it and found the sonic impact rather slight, if notable on VERY CRITICAL audition.

Ciao T

Posted by Romy the Cat on 01-24-2005

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 Thorsten wrote:
Then it does exactly what is asked of it, I asked JB to design it for me PERSONALLY as a "wire with gain". I have been on previous occasions been unconvinced of many stepup transformers, be they sowter, amplimo, EAR or jensen.

The only ones I got to like where old Mike stepups from Neve Mixing Desks and some ancient and I mean ultra-ancient Ribbon Mike stepups pulled from an old grampian console. Both of these where of course virtually single pieces and even they retained some colorations.

The TX-103 has come very close to a "wire with gain", which is more than I can say about most other passive or active steups. Not everyone wants or needs a wire with gain, well as the BBC commented, other suppliers exist.... ;-)

Well, I agree that “just gain” itself is a noble task and that there are not a lot of transformers that it without screwing many other things. However, I have seen the results (and ET transformers is the example) after which the "wire with gain" not considered anymore as an “interesting” accomplishment. From the place of my today’s understanding the benefits and the abilities of MC transformers I would say that a good transformer must besides to be a "wire with gain" be able to increase substantially a subjective dynamic range of the system. I am not talking about a minor difference but about the very-very aggressive increase of dynamic range that would be similar of moving from 88dB sensitive speakers to 112dB sensitive. The TX-103 unfortunately does not do it and therefore I said that it does “just gain”.

The caT


Posted by Romy the Cat on 01-24-2005

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T, although I am not in disagreement with what you suggest but I have to admit that your expectation of user applications dose not make sense to me. I’m taking the use of a transformer in a system and getting a result out of it instead of building a universal product available for resell.

I person has one cartridge, installed at one arm and a person has it for 3-5 years (some people much longer). Why the person needs a severely sound-worsening gain switch or an ease-changeable loading resistor (foolishly placed at the secondary coil instead being placed at the grid of the input tube)?

After the person have found the correct combination between his cartridge, loading and gain then it will never change and the person do not need all of this “accessories”. Therefore all those “added values” that Bent Audio and others stick into TX-103 are juts a leisure for the Morons who makes those changes each weekend and then compare their full of “wisdom” notes at AA.  Is it the tarter customers for the Bent Audio?

If people happen having multiple arms and multiple cartridges then they most likely have multiple transformers and multiple phonocorrectors (or multiple inputs with the defend loads…)

So, I have no idea who was a target market for those TX-103 optimization kits and I find them totally unnecessary, even “bad for sound”.  After all necessary configuration found these entire things should be permanently soldered and never touched again until the needle or the corrector change.

The Cat


Posted by Thorsten on 01-24-2005

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Hi,

 Romy the Cat wrote:
So, I have no idea who was a target market for those TX-103 optimization kits


There is no "TX-103 optimisation kit". There is a commercial stepup product. It was designed to be sold through current, existing delaerships and to people to whom the recommendation:

Remove the Stepunits cover.

Unsolder the following solder bridges according to the diagram 1 below and resolder them according to diagram 2 or 3 and evaluate which sounds best to you and then solder the whole thing in place.

We could of course have fitted plug in jumpers to a PCB for such people and Socket pins to insert loading resistors. Of course, most jumpers sound a lot worse than a good switch, and they still have this "take off the top" problem. 

MF Audio might offer a fixed ratio stepup at some time, but you cannot expect Dealers to reconfigure them for customers (I'd not let most dealers within a mile of a soldering iron) so one would have give the Dealers a switchable version they can lend to the customer (and do so for free or at significant discount) and all that strikes me as a lot of hassle. Therefore the commercial stepup is likely to remain switchable, intending to give the customer the confidence that he can take the stepup home and get the best from it by simply twisting some knobs.

As said before, I AGREE that this is suboptimal, but it seems to fit the market more or less well enough.

And honest, I'd rather have a product out there that the user can easily find the best system match than one that will not match many systems and where the customer cannot be bothered to invest the time to tinker and solder for a few hours and them promptly proclaims on the net his "Dominator X" $ 5 active headamp is miles better and people should not bother with my product....

So, the current MF Audio stepup is what it is.

Anyone wanting to just buy bare transformers, braid the input wires and twist the output wires, apply some screen to the output wires and then solder an RCA in-line socket to the input wires and an RCA Plug to the Output is welcome to obtain the TX-103 from one of the various DIY Distributors (Steinmusic Germany, DIYHIFisupply Hong Kong, Hornet HiFi Croatia and Bent Audio Canada) and to do so.

All the required info to so (for anyone actually capable of doing so anyway) is on the Stevens & Billington website (I know, because I wrote it)...

Of course, perhaps S&B & MF Audio would be best off dropping the supplies to the DIY Market, changing the relatively inexpensive and functional casework for something nice, solid and heavy that screams "High End" and charge three times as much for products and offer only "optimised" versions which require a large deposit to allow audition. Maybe then people would take the products more serious. I personally would not like such an approach much and I doubt too many others would be happy. 

Ciao T

Posted by AnonymousUser on 04-29-2006
Hello Romy

I read with great interest your site and enjoy your point of view. 

But I have a question for you.
There are two Expressive Tech SU-1 for sale on Audiogon, but the face plates look different.

I ws wondering if they are the same with the exception of the face plate and if they are not which should I buy.

Paul

Posted by Romy the Cat on 04-29-2006

Paul,

As far as I know the Expressive Technologies have only tow models: the regular transformers and toroidal transformers. The toroidal version (SU-2) is not available publicly which left that whatever the Expressive magnetic available out there it would be the only SU-1 version that Expressive even produced. The outer box should not be important as the SU-1 has 4-5 outer boxes, one inside another, like the Russian Nesting Dolls. The transformers themselves are remarkable small, in fact insultingly small for this box. I have no idea what they sell at Audiogon and what the history of those units. The Expressive was a small company that made the transformer by the small production runs of 10-50 units. It is possible that they had a run with different face plates or somebody remodeled them. I personally have seen only plane-vanilla black units with the Expressive Technologies “embroiling” at corner. If you are interested to buy one then you should more be concern that the Expressive would work with your phonostages. This transformer might be very finicky ….

Rgs,
Romy the Cat

PS: I moved your post form the open forums to the audio section. I hope you do not mind.


Posted by Paul Costa on 04-29-2006
Hi Romy      

Thanks for your reply.

I am in the market for either a new pre-amp or phono and line stage.

I know they need around 47k for optimal loading, but what else might I be concerned with.

Did you have a look on Agon at the two there.  The one I was thinking of buying he says is from 1987.  I amy pick it up myself to make sure everything is ok with it.

Paul

Posted by Romy the Cat on 04-29-2006

 Paul Costa wrote:
Thanks for your reply.

I am in the market for either a new pre-amp or phono and line stage.

I know they need around 47k for optimal loading, but what else might I be concerned with.

Did you have a look on Agon at the two there.  The one I was thinking of buying he says is from 1987.  I amy pick it up myself to make sure everything is ok with it.
Paul,

I would like do not downsample myself down to the purchasing advisement. I feel to board to do it. There are plenty morons out there who would be happy to advise you, regardless their sense of the subject…

Anyhow, staing further away form your Audiogone frustrations: generally, the 47k recommendation is irrelevant as it would depend how much you are wiling to load your cartridge.  If I remember correctly the Expressive would like to see low input capacitance, 100 pf would be optimum. In reality everything is more completed and I have seen how Expressive (I had 3 SU-1 and 2 SU-2) behave very differently with different phonostages (tried with few). If you are local with the saler then leave him money bring the Expressive home and try it with your phonostages. If it Expressiveise Sound then you would nee 3 seconds to detect it. If you do not say “Holly shit!” after second note you heard then your phonostage was not good to begin with and even the Expressive will not help you. I can not say, unfortunately, which specific property of phonostage to look for.  Yes, BTW, keep your cable after the Expressive as short as possible and as good quality as possible. The cable after the Expressive and before the phonostage is the most sonic inflicting cable in your entire system.

Rgs,
Romy the Cat


Posted by Paul Costa on 05-08-2006
Hello Romy

I had a friend pick up the Expressive from the seller for me.  I am a little disapointed in the physical apperance as there are a few scratches and the seller thinks I a crazy for saying so.

I haven't tried it yet as my friend still has it and I am four houe away in a car ride.

But as for cables, when you mean quality do you also mean a well shielded cable or one that you think sounds good.

Also what about placement do I have to be careful of what I put it next to.

Paul

Posted by Romy the Cat on 05-08-2006
When I said “cable” then I meant whatever cable might mean, the sonic qualities and whatever comes with it. You cartridge with it 2mV drives a cable to a transformer, for instance 1M that has impedance, capacitance and so on. The transformer has 26dB-28sB gain and what it goes it multiply the presents of the after-transformer cable in 26 times. As the result the cartridge see 1M before-transformer cable and 25M of after-transformer cable. Each sonic characteristic of that cable that you might observe user normal conditions would be also 26 times more right in your face. This cable is the most critical of all. There is another thing. The transformer helps with voltage but loosing current. Most of cables, if the current loaded “sound” much better. In the after-transformer cable, the current is insultingly low, not to mention that it has very low current initially from the cartridge…. To insult the injury I would ad that some of the cables could not be burned by higher current to sound OK at the low current…. Anyhow, you should not be worrying about it for now as you should be able to hear the ET contribution without going into any fancy cabling arrangements

Rgs,
Romy

Posted by Romy the Cat on 04-18-2008

After years of using the Expressive Technologies SU-1 and SU-2 step up transformers I come across to a fact this morning that the Expressive was reviewed by Robert Harley in June, 1992. I read the Expressive’s preamp review but I never seen this one. I will not comment on the Robert ’s founding and just provide the review. I just mention that something was very sick in Robert Harley’s mind when he loaded the SU-1 transformer to Vendetta Research phonostage. Vendetta is MC-level corrector with maximin input impedance of 200R. What the hell he anticipated to hear loading his cartridge with 200/625=0.32R. It was .32R!!!!

I reprint the article here in order to preserve the writing for posterity as who know tomorrow the Stereophile will be sold to a big real-estate agency and they will be publish review about colonial houses.

Expressive Technologies SU-1 moving-coil step-up transformer
By Robert Harley  (Stereophile, June, 1992)

http://stereophile.com/phonopreamps/692su/

What's this? A review of a $3000 moving-coil step-up transformer in this digital day and age? Yep. Although the market for such a product is small, the fact that the Expressive Technologies SU-1 step-up transformer enters previously uncharted state-of-the-art territory warrants these pages of editorial space. Furthermore, LP playback appears to be alive and well at the upper end of the high-end spectrum, a market segment addressed by the SU-1 (footnote 1).

Before getting to the SU-1, a few words about Expressive Technologies are in order. In many ways, they are like the small tweaky outfits that started the high-end audio business; they have a zeal for achieving the best possible sound without regard for user convenience or what the product costs. Unlike shaky garage operations, however, Expressive Technologies builds their products to the highest mechanical standards and fit'n'finish. Further, because the company is a labor of love by three audiophiles who have achieved financial success in other fields, Expressive Technologies is likely to be around for some time.

The SU-1 moving-coil step-up transformer is an offshoot of Expressive Technologies' research into designing a very ambitious electrostatic loudspeaker. Part of that design effort included building a step-up transformer for the electrostatic panel. The knowledge gained in transformer design was applied to stepping up a moving-coil cartridge's output signal. Incidentally, the SU-1 step-up was designed by a Bell Labs researcher who holds a PhD in analog circuit design.

The SU-1 step-up is one of only two products offered by Expressive Technologies. The other is the IC-1 interconnect. Because virtually all SU-1s are sold with two pairs of IC-1 (for reasons described later), this review is in essence an assessment of both products. In addition, I will comment briefly on the IC-1's sonic qualities when used with other products.

The SU-1 is definitely not what one expects a moving-coil step-up transformer to look like. At 19" wide, over 5" high, and weighing 35 lbs, the SU-1 is clearly a serious product. The rear panel holds two pairs of gold-plated RCA jacks and a ground terminal. There isn't much to talk about inside the unit; the SU-1 is a black box that contains two other black boxes—the left- and right-channel transformers. Build quality is excellent.

A few other technical notes: the SU-1 works best with low-output moving-coils, especially those with output voltages of less than 0.5mV. The relatively low-output (0.3mV) AudioQuest AQ7000 cartridge I used was a good match for the SU-1, while many of the newer high-end moving-coils have output voltages of 0.18mV, making them good candidates for use with the SU-1. However, cartridges with a high output impedance (above a few ohms) should be avoided. Not all phono stages work well with the SU-1; the phono stage input impedance should be high (47k ohms is ideal). Phono preamp gain is also a critical factor in how much difference the SU-1 can make to the system. High-gain phono stages don't need the stepped-up voltage, and some may be overloaded by the SU-1 when driven by even moderate-output moving-coil cartridges. The ideal conditions for the SU-1 are a very low-output moving-coil and a 47k ohms input impedance moving-magnet phono stage.

Listening

The SU-1's effect on the musical presentation varied from the dramatic to the subtle, depending on the phono preamp used with it. I'll start with the dramatic, heard when auditioned with an Audio Research SP11 Mk.II. The combination of the fairly low-output AQ7000 and the moderate-gain SP11 really benefited from the SU-1. First, the dynamic contrast was greatly improved, with a wider range between loud and soft. The background was "blacker," and high-level transients were sharper and more lifelike. In addition, there seemed to be greater resolution of dynamic gradation, the music taking on finer degrees of dynamic shading. Overall punch and slam were greatly improved; inserting the SU-1 in the phono chain was like giving the system a shot of steroids. Drums had more impact (especially kick and snare), contributing to a greater feeling of life.

Because much less gain was needed in the SP11's line stage with the SU-1, the noise floor was noticeably lower. Soft passages were more clearly delineated, rather than having a light hiss superimposed on them. This was especially apparent with records cut with low signals and music with very wide dynamic range. This improvement alone may be worth the price of admission.

I also found the SU-1 increased the "see-through" transparency of the presentation. There was a greater clarity that provided a clearer view into the soundstage. Soundstage depth, width, and focus were all improved by the SU-1. The impression of instruments and voices hanging in three-dimensional space was heightened, as was the feeling that a slightly opaque veil had been removed from between me and the music. The SU-1 was the antithesis of murky and congested.

The SU-1 also made instrumental textures more liquid and smooth. The treble, in particular, was more gentle and relaxed. Despite the softer presentation, there was a distinct impression of hearing more detail and information. The SU-1 uncovered another layer of minute detail and subtlety in the music. The enhanced detail, however, tended to reveal the subtle fabric of finely woven textures, rather than merely emphasize etch and grain.

The bass also benefited from the SU-1, becoming rounder and more liquid, with a greater naturalness. Acoustic bass had a warmer, less sterile and stultified character. Pitch definition improved, allowing greater resolution of individual notes. This was especially apparent during Ray Brown's playing on the Bill Evans record Quintessence (Fantasy F-9529). The instrument had a "fuller" sound, and was just more natural and right. Overall, the SU-1 step-up and IC-1 interconnect did wonders for the AQ7000/SP11 combination.

Next up was the Mod Squad Phono Drive. With both moving-magnet and moving-coil inputs, and front-panel selectable loading, the Phono Drive provided a wider range of conditions. I compared the sound of the AQ7000 going directly into the moving-coil input vs the SU-1 in the signal path connected to the moving-magnet input. This is a typical real-world condition; the SU-1's voltage gain replaces the additional circuitry of an active moving-coil stage.

Like my impressions with the SP11, adding the SU-1 was a revelation. The Hales Signatures seemed to have another octave of bass extension. The greater weight and power in the bass was not a subtle improvement. Transient leading edges were much more sharply defined, giving the presentation a greater sense of immediacy. The drums and percussion on the LP Roland Vasquez and the Urban Ensemble (Arista/GRP 5002), for example, took on new life and drive.

The SU-1 also had a dramatic effect on soundstage depth and apparent hall size. The presentation became deeper and more spacious, with a feeling of instruments floating in three-dimensional space. On the Robert Lucas album Usin' Man Blues (AudioQuest AQ-LP1001), for example, the space surrounding the harmonica and vocal bloomed to give a wider and more open perspective. There was a greater sense of the loudspeakers falling away and being replaced by images hanging in space. The sound was just more palpable and real with the SU-1. After hearing the SU-1, it was not easy to go back to listening without it.

To see what the effect of the SU-1 would be on an excellent MC stage, I used it to drive John Curl's Vendetta Research SCP2B (footnote 2). Despite the fact that the Vendetta SCP2B is designed to accept a moving-coil output without a step-up device, it was not overloaded by the SU-1 when driven by the relatively low-output (0.3mV) AudioQuest AQ7000 cartridge. However, as the Vendetta has more gain than the SP11 Mk.II, the improvement in S/N ratio was less meaningful. The Vendetta was quiet with or without the SU-1. I didn't hear the dramatic increase in dynamic contrast with the SCP2B that I did with the SP11, and with the Vendetta's variable input impedance adjustment set too low, the sound was rolled off in the treble and lacking life. The presentation was also a little on the lightweight side, the opposite character heard with the SP11. Not a recommended combination.

I must point out that I was unable to audition the SU-1 with any interconnects other than the IC-1 because of high hum levels with other interconnects. Whatever the grounding arrangement, I got an unacceptable amount of hum without the IC-1 interconnect (which has separate ground wires).

While I'm on the subject of the IC-1 interconnect, which costs $595/meter pair, terminated, I'll take this opportunity to relate my experiences with it. First, I can say without hesitation that the IC-1 is the best-sounding interconnect I've auditioned. I've had much experience with it over the past several months, and recently experimented with various interconnects between the Mark Levinson No.30 digital processor and the Audio Research LS2. In all cases, the IC-1 was clearly superior. There was a more natural portrayal of instrumental and vocal timbres. The IC-1's crystal transparency provided a more realistic feeling of the actual instruments' sound. There was also more inner detail and greater resolution of fine textures. The IC-1 presented another level of detail and nuance in the music. The bass was full and rich, yet tuneful and articulate. The treble was more laid-back than many interconnects, yet never sounded lacking in life. In short, the IC-1 excelled in every area, especially the first two noted: natural presentation of timbres and resolution of inner detail.

Despite the IC-1's superb sonics, it's not for everyone. Not only is it thick, bulky, heavy, and very difficult to bend, it's absurdly so—like a garden hose filled with ice (footnote 3). If you're going to set up your system once and not change interconnects, the IC-1's unequaled musical characteristics will make the effort worthwhile. Those who, like reviewers, constantly change equipment and interconnects, are cautioned about the decidedly user-unfriendly nature of the IC-1. Why is it the best-sounding stuff always seems to be the most difficult to use?

Conclusion

In suitable systems, the Expressive Technologies SU-1 step-up transformer can dramatically improve the quality of LP replay. The lower noise level, increased dynamics, more spacious soundstage, greater transparency, and more natural presentation of instrumental textures rendered by the SU-1 were nothing short of stunning. In fact, I found it hard to go back to the SP11 and Phono Drive without the SU-1 in the chain. These impressions will not hold true for all phono stages, however. Because the degree of improvement rendered by the SU-1 varies greatly with the phono section, prospective buyers are urged to audition the SU-1 with their preamp and cartridge before making a buying decision.

Would I spend $2950 for the SU-1? Without hesitation. It really was a quantum improvement, one I believe justified by the SU-1's not insignificant price. I should reiterate that using Expressive Technologies IC-1 interconnect in the phono chain is essential, both because of the potential for hum and the synergistic sonic effects of the two products. The cost of two pairs of IC-1 should therefore be factored into the SU-1's price.

If you love LPs and have a low-output moving-coil and a preamp with a high impedance input, the SU-1/IC-1 is a "must hear" product. But I'll warn you: Once you hear your favorite LPs through the SU-1 step-up and IC-1 interconnect, you may not want to live without them.

Description: Moving-coil step-up transformer: Voltage gain: 28dB. Turns ratio: 25:1. Input impedance: 75 ohms. Recommended preamp input impedance: 47k ohms, 100pF. Frequency response: 0.1Hz–250kHz, +0, –3dB. Phase shift: <3° at 20kHz. Group delay variance: <100;us (20Hz–20kHz). Noise: >–100dB (referenced to 0.5mV). Maximum input voltage: 1V. Maximum output voltage: 25V.
Dimensions: 19" W by 5.4" H by 8.25" D. Weight: 35 pounds (net).
Price: $2950 (1992). Approximate number of dealers: 5.
Manufacturer: Expressive Technologies, P.O. Box 6401, Holliston, MA 01746-6401 (1992). Company no longer in existence (2008).

Review System

I auditioned the SU-1/IC-1 combination over the past few months. Phono preamps used in conjunction with the SU-1 included the Audio Research SP11 Mk.II and a Mod Squad Phono Drive, all driving (independently) an Audio Research LS2 line-stage preamp. Turntable was the Well-Tempered with its tonearm modified by LP Labs (see Vol.15 No.1, p.224).

Loudspeakers were primarily Hales System Two Signatures, augmented with a Muse Model 18 subwoofer. Power amplifiers were my long-term favorites, the VTL 225W Deluxe monoblocks, or the two solid-state amplifiers reviewed in April (Parasound HCA-2200 and McCormack DNA-1. Interconnects were the Expressive Technologies IC-1 in the phono chain, Straight Wire Maestro between preamp and subwoofer, and AudioQuest Diamond between subwoofer and power amplifiers. Loudspeaker cable was a 3' bi-wired run of AudioQuest Dragon/Clear (with the VTLs) or 8' runs of AudioQuest Sterling/Midnight (with the two solid-state amplifiers).—Robert Harley

Measurements

When I measured the SU-1, the results appeared to be more related to the test setup than the SU-1's intrinsic performance. Just as there was a large variability in sound quality depending on the phono preamp used, the measurement results were highly dependent on the test conditions.

I initially measured significant rolloffs at the audio-band frequency extremes—down 2dB at 20kHz and nearly 3dB at 20Hz. These rolloffs would be highly audible, yet no rolloff was suggested by my auditioning. The cause of the measured rolloff was twofold. The 25 ohm source impedance (the lowest possible setting) of the Audio Precision System One's signal generator formed a voltage divider with the SU-1's 75 ohm input impedance. Because the transformer inductive reactance presents a much lower impedance at low frequencies, more and more of the voltage is dropped across the source impedance as frequency decreases instead of across the transformer input. Hence the bass rolloff (footnote 1).

The AP System One's relatively high output impedance (compared to a low-output moving-coil, typically less than three ohms and sometimes a few tenths of an ohm for the ultra-low output types) was also responsible for the treble rolloff. A transformer's output impedance is a function of the source impedance driving the primary and the transformer's turns ratio. Specifically, the transformer's output impedance is equal to the square of the turns ratio multiplied by the source impedance. With a source impedance of 25 ohms (the System One's generator), and the SU-1's 25:1 turns ratio, the output impedance thus becomes very high (nearly 16k ohms). Further, the capacitance the secondary winding drives is also a function of the input capacitance: the source and interconnect capacitance are also multiplied by the square of the turns ratio. A few hundred pF at the input results (in the SU-1's case of a 25:1 turns ratio) in several tens of ;uF the output must drive. This high output impedance and high capacitance form an RC filter across the output, dropping high frequencies across the RC network instead of across the load, and rolling off the treble (even with the System One's 100k ohms input impedance).

JA remeasured the transformer, driving it with the Krell KBL line-level preamplifier to get a low enough source impedance (2.2 ohms), though this does make the test signal a little noisy. His frequency response, taken at 5mV input, is shown in fig.1. The solid lines are the left channel; the dashed, the right channel. To show the effect of load impedance, JA used the Audio Precision's inputs set to 600 ohms—the curves that droop above 4kHz—and 100k ohms—the curves that peak above 50kHz, reaching about +8dB. (Into the lower load, of course, the absolute level dropped by 10dB or so.) The measured voltage gain at 1kHz into the 100k load was almost exactly the specified 28dB.

Fig.1 suggests that the SU-1's balance will be highly dependent on the associated components, primarily the cartridge's output impedance, the interconnect capacitance, and the phono stage input impedance. Indeed, this was suggested by the auditioning. Potential purchasers are advised to audition the SU-1 in their own systems before making a buying decision. Basic guidelines, however, can be offered. The SU-1 will work best with low-output moving-coil cartridges (both because of their low output impedance and need for higher gain) and 47k ohm input impedance moving-magnet phono stages. The combination of the AudioQuest 7000 cartridge (0.3mV output and 2.5 ohms output impedance) and the SP11's 47k ohm input impedance was a good match for the SU-1. (The Lyra Clavis and Parnassus have an output impedance of less than 1 ohm and may benefit even more from the SU-1.)

The putative Achilles' heel of step-up transformers is their distortion and overload characteristic. Well, the SU-1 proved exceptional in this regard. Fig.2 shows the THD+noise in the transformer's output for output levels ranging from 0.1V to 50V, equivalent to input levels of 4mV to 2V. The three curves shown are for 20Hz (top), 20kHz (middle), and 1kHz (bottom): in all three cases, the sloping curve from left to right represents the system's noise floor; as the signal rises, the slope down eventually changes to a slope up, indicating that the distortion products have risen above the noise. At 1kHz, you can see that this change happens at a whopping 15V output, equivalent to an input of 600mV. With reference to the standard MC output of 0.5mV, this is equal to an overload margin of 61.6dB! The phono stage input will clip long before the SU-1. Even at the frequency extremes, the "bend" in the THD characteristic occurs at very high input levels, equivalent to margins of 44dB at 20Hz and 31dB at 20kHz. (The reduced margin at 20kHz is due to the RIAA curve pre-emphasizing this frequency on the LP by almost 20dB compared with the level at 1kHz. This factor also makes the reduced margin of the transformer at very low recorded frequencies less of a problem, though it must be remembered that warp information comes through at full level.)

The final graph (fig.3) shows the manner in which the distortion changes with frequency. To get sensible readings above the noise floor, I drove the transformer with a 100mV signal. Somewhat surprisingly, the left-channel distortion in the bass region was higher than the right-, though at the kind of low-frequency levels typical of an MC cartridge, there won't be any distortion! The left channel also shows a slight but still negligible rise in distortion above 25kHz. The flat curves in the center represent the distortion in this region dropping below the noise floor.—Robert Harley

Footnote 1: The relationship between inductive reactance (a force which opposes current) and frequency is stated in the formula XL=2pifL. This relationship is linear; double the frequency and the inductive reactance doubles. At DC (0Hz) there is no reactance and the source sees only the DC resistance of the transformer primary.

Posted by Axel on 07-24-2009
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Hi Romy,
did you experiment with either primary or secondary SUT loading using your various carts? If so would you mind to share any of your findings?
Thanks,
Axel
PS: Not sure if you have any 'knowledge tree' info about MM carts, or are you still of your earlier opinion: "Not good enough"?

Posted by Romy the Cat on 07-24-2009
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 Axel wrote:
…did you experiment with either primary or secondary SUT loading using your various carts? If so would you mind to share any of your findings?

Or course I did, anyone did. I am not sure what findings you would like me to share as they are no different then anyone else’s. I am not a big fun of primary loading, put in this way I see no needs for it with my transformer and my cartridges but fine-tune secondary loading is a very standard practice. My both stereo arms (Ortofone Jubilee and Ortofone SPU Classic with ellipse) are loaded with 57.6R and my mono arm (SPU Classic Mono) is loaded with 42R

 Axel wrote:
PS: Not sure if you have any 'knowledge tree' info about MM carts, or are you still of your earlier opinion: "Not good enough"?

I do not use MM cartridges.

The Cat

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