Dedicated phono-pre for MM only?

This thread has been informative and I'm better understanding some of the nuances of phono stage design, both MM and MC architecture.

And I'm beginning to see the value in having a dedicated MC phono preamplifier if LOMC cartridges are preferred. Why bother with 40 dB gain and 47K loading for MM cartridges. The design would, at most, have binding posts to change loading resistors. Being able to change the amplification (gain) would be handy but not necessary if the output voltages of the preferred cartridges were within a fairly close range.

Is such a phono preamplifier available?

Tom

Oops. Meant to include a thank you to Axel and Lewm for answering with understandable information. And Axel, I didn't intend to sidetrack the thread with my question about dedicated MC phono preamps. Just seemed like a similar question in that having phono stages designed specifically for the type of cartridge engine makes sense.

What I'm not sure about is whether you'd be able to hear the difference (as Lewm suggests) between a dedicated minimalist design vs a preamp with variable gain/loading options. I often read that it does make a difference, that having switches or plugs or jumpers degrades the signal, but as Lewm also suggests, if the problem is that noticeable, why do even high end manufacturers provide gain/loading flexibility in their phono preamps?

Tom

Hi Tom,
you say:
>>> Just seemed like a similar question in that having phono stages designed specifically for the type of cartridge engine makes sense. <<<

I have the idea that Raul will be the person to explain to you in his words why he has opted for two **dedicated** phono-pre option in his 3160 and NOT a one-serves-all (just with a jumper to switch from 40 to 60dB).

Having read all my and Kirkus' comments should have made the point, but let's see if Raul can put it into a 'nut-shell' for us.

Greetings,
Axel

In my view, one of the hard to resist features of the 3160 (Raul's product) is the completely separate MM and MC phono stages, not to mention the fact that both are balanced circuits (or at least I know that the MC one is balanced).

Raul might respond to Tom's question about why "high-end" phono preamps have switchable load resistances by saying that there is a demand for it among end-users, for the sake of convenience, not optimal sound quality. Most end-users of such products want remotely switchable everything, so they don't have to get off the couch. Raul wants optimum performance as his end-all and be-all. What I meant to infer when I said that most of us would not know whether switches degrade the sound is that most of us have not done the experiment properly in order to make a judgment. Most of us have one phono stage which either does or does not have switches in the signal path. And no one (other than Raul) has come forward to say that removing switches from phono inputs has made an audible improvement in sound. Or that adding same caused a deterioration. For my part, I own an Atma-sphere MP1 in which I have made considerable mods to the phono stage. The MP1, like Raul's preamp, has no switches in the phono input, but one can change load resistance by installing resistors between two screw terminals on the outside rear of the chassis. Purist that I am, I have never used those screw terminals for loading or for anything; I solder my load resistors right at the grids of the input tube (or the gates of an MAT02 NPN transistor, in the case of my modified unit). Oops, I am off-topic.

One thing that comes out of this so far, thanks to Kirkus and Quiddity, is the concept that there truly IS a difference, primarily at the input voltage amplifier stage, between an ideal MM phono and an ideal MC phono. One topology does not ideally fit all. I'd still like to hear more from Kirkus on balanced mode with an MM cartridge. Anyway, I've decided that I do want a separate dedicated MM phono stage, which is kind of where I started but now I have more info to go on.

Hi, Lewm, nicely stated explanation. And after reading Raul's responses again I see what was implied, that convenience may override preamp performance. I can certainly understand the convenience factor.

But Axel, I'm confused a bit by your comment that the 3160 has a jumper to change from 40 dB to 60 dB of gain. Are jumpers considered to be acceptable, that is, they do not degrade signal path, at least in the amplification portion of the circuit? Or did I interpret your comment incorrectly?

Tom