With the exception of the occasional strain gauge or moving iron cartridge, most cartridges are either moving coil or moving magnet designs. The typical moving magnet cartridge has a high output whereas the typical moving coil cartridge sports a significantly lower output. There are exceptions of course. Some moving coils are higher output (north of 1.0mV) and some well known cartridge makers, notably, Grado, have been known to produce a lower output moving magnet or moving iron cartridge.

For quite some time audiophiles have displayed a distinct preference for moving coil cartridges, which are said to be faster, more informative and significantly more extended at the frequency extremes. However, by my lights, many audiophiles confuse a somewhat tizzy, etched, lightweight presentation with high resolution and speed. And so, many moving coil designs strike me as a bit too much bone and too little meat. Still, there is no denying that the best moving coil designs are nimble, informative and transparent. They can also be vivid and immediate. By comparison, many moving magnet can sound fat and sluggish.

However, among the advantages of moving magnets is their apparent warmth, and their compatibility with a variety of different arms and phono preamplifiers. In contrast, low output moving coils require more gain than the average phono preamplifiers can provide – at least quietly – and mate successfully with fewer arms.

Some audiophiles have tried to get the best of both worlds by purchasing high output moving coil cartridges. The idea is to secure the performance of moving coil cartridges and the compatibility of moving magnets – especially the ability to use the typically quieter moving magnet stage of a phono preamplifier. I’ve tried my share of high output moving coils, and my experience has been that one is more likely to get the worst of both worlds than the best of each. High output moving coil cartridges do not load appropriately into the average moving magnet phono stage, and the sound of such cartridges has always left me cold – perhaps for that very reason.

In the past few years, I have listened to and owned only low output moving coil cartridges. My favorites have been two versions of the EMT (Roksan and Brinkmann) and the SPU Classic – especially the Shindo modified version, which so bests the standard Classic as to render it pedestrian by comparison. Judging by the brisk sales of Shindo SPUs and various upgrade purchases, my view is shared by many others who were previously contented owners of a Classic.

If you prefer tube phono stages (who doesn’t?), then one problem with low output moving coil cartridges is that the number or type of tubes that are required to provide the necessary gain is likely to result in a lot of noise. Typically, the noise will obscure micro detail and micro dynamics, while adversely affecting imaging and transparency. On the other hand, I have rarely enjoyed listening to solid state phono preamplifiers. I have admired the performance of many, but fallen in love with none. You pay your money, you take your choice: cold and distant or noisy. I’m from NY City. I can handle noise, but nothing cold and distant. If I have to choose, I’ll live with some noise. Like any sensible person, I’d prefer not to have to.

One solution to this dilemma is provided by so-called step up transformers. Some of these are standalone components while others are included in the phono stages of full function preamplifiers. Though few full function preamplifiers have internal step up transformers, my Shindo preamplifier does; indeed, all but one Shindo preamplifier comes with an internal step up transformer.

A standalone step up transformer is very much a specialty product in several ways. Most standalone step-ups are purchased to compliment the moving magnet phono stage of an existing preamplifier, and so when one purchases a step up, it is normally loaded into the already existing moving magnet stage. Rarely, but sometimes, someone will purchase a step up transformer even though his preamplifier already includes a phono stage capable of being driven by a low-output cartridge.

An external step-up can be configured to work optimally with particular cartridges. Transformers excel with the cartridges even if such a strategy means that their performance may be compromised when used with other moving coils. In contrast, the typical low output moving coil stage of a preamplifier is designed to work well enough with a wide range of cartridges and is thus not optimally configured for any cartridge. A user may be particular fond of a particular cartridge and having a step up that is configured for it may make a significant enough difference in performance to warrant substituting a standalone step-up for the one that is available on board.

Over the past two years, I have had some considerable experience with various step-up transformers from both the Shindo and the Auditorium 23 line-up. I have become familiar with the step-ups that are internal to the Monbrison and Catherine preamplifiers of the Shindo line, as well as with the standalone Arome, which is said to be roughly equivalent to the step up that is inside Shindo’s top of the line Petrus preamplifier. In my reference system, I run the Shindo SPU into the Arome step up into the moving magnet input of the Catherine. I have compared this combination to the internal step-up of the Catherine which I have compared to the internal step-up of the Monbrison. I have not used the Arome with the moving magnet input of the Monbrison.

In addition, I have employed three Auditorium 23 step-up transformers: the basic step up designed for the Denon 103, the one under review here which has been configured explicitly for the SPU, and the brand new, top-of-the-line step-up recently designated the world’s best by a prominent French audio magazine (and that after competing with some of the best and most well known alternatives, at least one of which I have owned and continue to). My experience to date with the top-of-the-line A23 step up has been very limited; even so, it has left an impression on me that I am not likely soon to forget.

I employed the basic A-23 step up designed for the Denon with both the Denon 103 and two versions of the EMT. While its performance with the Denon 103 was exemplary – compensating for the cartridge’s two main limitation (restrained dynamics and an apparently rolled off top end) – the Denon step up was a spectacularly good match for both EMT cartridges with which I used it. I had been using a Well Tempered Reference TT with a Shiraz (modified EMT) cartridge. I loved the combo, but the overall presentation was just as various reviewers of the Well Tempered had consistently reported it to be: a bit less dynamic than desirable and a bit shut down on top, perhaps a tad deprived of air and extension on top. Running the EMT through the A23 Denon 103 step-up changed my conception of the Well Tempered completely. It took the performance of this great value TT/arm/cartridge combination to a performance level comparable to the best I had heard. The Denon 103 step-up transformer sells for $975.00 and at that price provides an upgrade in sound that is worth several times its cost. I am not claiming that this is the effect it will have in every environment, but I can recommend it as the best single addition one can make to a Well Tempered/Roksan Shiraz combo.

As I mentioned above I have had a lot of experience with step-ups for the SPU Classic: the Monbrison, Catherine, Arome step ups from Shindo and two step ups from the Auditorium 23, including this extremely reasonably priced ($1,295.00) unit being reviewed here. When this step-up arrived, I placed it into the reference rig which included the Shindo Garrard 301 with modified SPU Classic cartridge, the Catherine full function preamplifier, the Shindo 300B Ltd amplifiers, a variety of cables and interconnects and several speakers, but mostly the A23 SoloVox and original JBL Hartsfield top loaders from 1953.

The A23 step-up may be small and easy to place, but it packs a hell of a wallop. In fact, getting the measure of this step-up was surprisingly easy. The A23 SPU step up is incredibly dynamic and extended, from top to bottom. It is neutral, extremely vivid and present. While it is by no means lean or bleached, it is not as weighty as the other step ups I had on hand. It is primarily about speed, openness, extension, clarity and presence. I have reason to believe that its designer, Keith Aschenbrenner, voiced this unit around the basic SPU Classic, which like the Denon 103, is all about tonality in the same sense that the folks at Audio Note UK claim their components are. Both cartridges favor the body of notes over the leading edge and weight over speed.

The A23 Denon 103 step up is a perfect complement for the cartridge of the same name. Played through it, the Denon 103 maintains its body and weight, but its apparent speed and resolution improve dramatically, especially throughout the upper registers. The A23 step up for the SPU has the same impact and would be a perfect match with the standard SPU Classic.

In contrast, the Shindo modified SPU Classic is already significantly more balanced and extended than the original. It also does a far better job on transients and micro dynamics. The net effect is that when mated with the Shindo SPU, the A23 step-up walks a tightrope. The dynamic realism is to die for. The presence and clarity are breathtaking. By comparison to the Shindo step-ups which are voiced around the Shindo SPU, the A23 can sound a bit less well-developed harmonically. But we are talking about very minute differences here, differences that would go unnoticed by most but which I am aware of just because I have spent so much time with all of these step-ups.

In fact, the difference is much more apparent when the Shindo SPU is played through the high end, cost-no-object step-up. In a recent comparison, this step-up took the measure of five of the leading step-ups in the world and I could see why. It maintained all the body and weight of the Shindo step-ups but presented the music with the same speed, clarity, presence and extension of its less expensive soul mate.

The A23 step-ups are, as a group, remarkable. The two relatively inexpensive versions – the one for the Denon 103 and this one for the SPU – are no-brainers. The Denon actually works with several cartridges. I found it to work magically with the EMT cartridge, even bettering its performance with the Denon. The SPU step-up is a perfect match with the basic SPU and anyone contemplating a purchase of an SPU should consider this step up virtually mandatory.

On the other hand, if you are contemplating purchasing the Shindo SPU (which is as good a cartridge as I have owned), then you may find the less expensive A23 step-up inadequately refined and nuanced. To get the most from that cartridge, you will have to take a deeper financial plunge. The internal step-ups in the Shindo preamplifiers were more suitable, if a bit less dynamically persuasive alternatives, to the A23 step up. On the other hand, the Arome is better still, and if my brief audition of it is any indication, the top of the line A23 step-up is better still: merging the harmonic and structural virtues of the Shindo step-ups with the speed, clarity, extension and life of the A23 step-ups.

The good news is that all of these step-ups are terrific values at different price points. Find the one that makes most sense for your pocketbook, the investment you have made in your system and those features of music reproduction that are most important to you. Fortunately for me, I don’t have to choose – at least not yet. And as long as I don’t have to choose, I am not going to. However you choose, you won’t go wrong. And that’s a pretty enviable position to be in.

The A23 SPU step-up is a best buy and if you are in the market for an SPU cartridge, you simply must audition it. My guess is that if you try, you buy.

Jules Coleman

review contents

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specifications | associated equipment

This review originally appeared in American Wired