MC phono stage without transformer?

MC stepup transformers introduce distortion based on hysteresis losses inherent in any inductive device. These distortions will mask a certain amount of detail and it is unavoidable.

In addition, the transformer, again like any inductive device, can ring, which is another kind of distortion (harmonic) that blocks detail and also makes things brighter. Ringing can be controlled to a certain degree by proper loading, but now things get a bit tricky as you have to make sure the cartridge is loaded properly as well. Of course you can ignore these things if you like but that means you won't get all the performance that the rig has to offer; its worth paying attention to.

OTOH there are phono sections that are completely MC capable; at least IME the very best stepup transformers are a degradation to the signal with such preamps. They are a great problem solver if your preamp is not already MC capable.

Tpsonic, the problem is that a lot of really musical cartridges have low output- 0.2mV to 0.3mV. Many tube preamps have troubles with cartridges this low.

One of the better SUTs we auditioned was made by Jensen, outstanding in the world of transformers with decades of experience.

We found that loading was paramount to reducing the artifact from the transformers. Jensen was well aware of the issues and has a loading chart for their devices along with a lot of popular cartridges.

Despite having the loading optimized, you could always hear the insertion of the SUT. Admittedly, it was more on the subtle side, but over a period of weeks and months you got to be more and more aware of it. Switching back to running direct (our preamps are designed for low output MC), there was an immediately noticeable improvement in air around the instruments, a greater sense of delicacy and obviously improved detail.

I suspect that having a direct-coupled output on both the preamp and the amps helps us hear extra detail, but one thing is for sure- it was the sort of thing that anyone in the room could easily hear and it was very repeatable.

I agree with Raul on nearly every point save that of the fact that tubes can work very well indeed with low output cartridges, direct.

Rccc, while it is true that there are transformers that were in the signal path in a lot of the recordings you favor, it is misleading at best to say that these are the **same** transformers as in the case of an SUT. Mic input transformers have different requirements as do line output transformers or the output transformer of the tube cutting amp for the LP.

You might be curious to know what an LP could sound like if some of **those** transformers were eliminated; the answer is "better!"

"High end audio" supports a diverse community: tubes, transistors, horns, CDs, LPs, headphones... there are people who are trying to get the best sound they can, those who buy only on cache, those who only care about the music and those for whom the experience of live music in the room is their only goal.

Raul and I represent two aspects of this community wherein we have the same goal of no-holds-barred experience of live music in the home, but he is solid state and I do it with tubes. In both our cases, since we are able to work with some of the best equipment available, the experience of the degradation that transformers bring is easily revealed. This is not so easy for those who have to struggle with a budget, who have sorted out how to get their hands on a low output cartridge but not figured out how to get the gain for it: the SUTs represent a compromise and as good as they get, they will always continue to **be** a compromise.

Raul and I would prefer to work without compromise to the best of our abilities.

A serious problem we all face on audio forums is that audiophiles all use the same terms but we don't have a good measure of the intensity of experience that comes with each term, regardless of the term. So at some point a leap of faith is required and often that leap runs short of expectation :)

In a nutshell, the more resolution you are able to get out of your system, the more artifact you will hear from SUTs.

Eldartford, of course no-one should be surprised that I don't like transformers :)

I did, however, outline some of the difficulties that one faces, bandwidth, ringing (distortion) and hysteresis losses (yet another kind of distortion).

You can dance through the parameters, trying to dodge the silver bullet and some good compromise is available. For example, by sacrificing a little LF bandwidth, you can reduce hysteresis losses, but they will still be there. Ultimately you are still dealing with a compromise.

This is not to say that a phono section with enough gain to start with does not represent some sort of compromise. For example, I prefer the sound of tubes, and tubes have a reputation of making more noise. What I found is that you have to treat the tubes the same way you treat transistors: fully-differential, with proper constant current sources, in order to make them be quiet. I found that making the proper constant current source was a huge part of that recipe.

So- we can get them to be quiet enough with the lowest output cartridges and at the same time the phono section is easily transparent enough to easily hear the insertion of the best SUTs we can lay our hands on. Now we all know that at the phono input, connections are very critical so for our evaluations we had to solder everything in. What seems to be coming out of this is that the more complexity, the less bandwidth and the less transparency.

So we endeavored to build a simple phono section. It has only two stages of gain and employs differential passive EQ. I don't know how much simpler it can get, in fact I've seen a lot of MM stages that have more complexity.

I guess the point is that my dislike of transformers is not **just** because I'm an OTL manufacturer, it really stems out of having worked with audio transformers a lot (and while they have always had some nice advantages, such as ground isolation): they always have an audible artifact. I really wish they did not, but there appears to be nothing that can be done to change that. You just have to avoid them if you can, that's all.

Raul is incontrovertibly correct about RIAA EQ. **Anyone** who says otherwise is not only wrong, but likely trying to sell you something :)

If you want to hear the recording engineer/musician's intention, your RIAA EQ should be correct. Incremental differences of a fraction of a db are readily audible, as the EQ covers a spectrum rather than a single frequency.

Again, just as in the case of detail, the better your system the more profoundly you will experience this. BTW I do not equate the cost of a system with how good it is!

Sirspeedy, Once the stereo LP was introduced, everybody began using the same EQ curve, which was defined by the RIAA. That curve was nearly the standard in the mono LP era with very little exception. It was during the 78 period that every label had their own EQ curve. Older tube preamps like the HK Citation 1, Marantz model 1 and the like had EQ switches for these curves.

There were a number of manufacturers of stereo LP matering electronics, for example we have the Westerx 3D cutting system outfitted on a Skully lathe. The limiter module allows you to create high frequency reduction through a series of switches. These are often reserved for master tapes wherein the mastering engineer is allowed to exercise some judgment. In addition, every LP mastering system has a 'signature' sound relating to the mastering head and the sonic character of the electronics.

But they all are based on the same EQ. Changing the EQ to taste or the like has some advantage with LPs that are poorly recorded (in this case the majority of DG classical would be a great example). For me this is very much like the CD problem: if I want the music, and its only on CD, I deal with the CD colorations because I want the music. Dealing with poorly mastered LPs is the same thing.

In a nutshell, IOW, a properly mastered LP, regardless of country of origin or label will sound its best with the standard RIAA curve. If not, there is a problem in the recording process.

Establishing a proper reference in this area is a hefty problem; one that we had to face down before we were able to make any significant progress, one that every high end audio manufacturer faces whether they know it or not, and one that every record label faces whether they know it or not (and a lot of them don't!).

One thing that I can tell you about that process is that to get to a real reference, you **have** to remove any sources of coloration that will obscure the recording. To us that meant transformers, interconnect cables, and other compromises in the signal path, like Class A vs Class B. Having gotten to a point where these sources of coloration are minimized it becomes very easy to hear what something like even a decent SUT does to the sound. That puts us back on-topic right? :)