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Dedicated phono-pre for MM only?

Hi All,
the subject of phono-pres, specifically 'adapted' to MM came up in some related postings.

IF, and only if, MMs are much to ones liking --- why spend your buck on some 'halve backed' 60dB plus, MC gain requirement, stage? Why not consider put the $$$ into a TOP 40dB gain stage of either SS or tube?

Raul had more thoughs on the subject as he mentioned before, and might share, why he knows that a TOP MM compared to MC stage circuit requirement might NOT be -one suit fits all-.

There could even be a nice argument to fit a tube gain stage only into an otherwise SS only system!?

Again, the $buck saved on the 20dB plus circuitry could be translated into the BEST circuit for an MM.
I realise, that most such stages were simply fitted inside some older TOP pre-amps, (e.g. Jadis...).
I have not come across a **dedicated** , current 40dB stage neither in nor outside a pre-amp.

Thank you,
Axel
axelwahl
axelwahl OP
788 posts
 
Hi Lewm,
sorry for having nicked your question, not that I knew. It just becomes the next relavant issue after you get 'closer' with the 'MM prered' thing.
>>> Ideally, I would build an MM phono stage myself, based on a single-ended LCR type of RIAA equalization or based on a true balanced circuit design. There are several schematics available for either topology <<<

Now you nicked MY question, it's actually behind the 'Allen Wright' inquiery. He apparently has some VERY well thought out designs. I think your point is a good one, and that's what I'm planning to do. Build my own and meanwhile listen to my 326 phono-boards (and use them as a referance to improve on)
Thanks,
Axel
lewm
13,204 posts
 
Allen has publicly disclosed his FVP5 and RTP3D designs. In fact, the front end of his RTP3D (using the MAT02 transistor that he mentions in TPCB2), is the prototype for the input stage of my phono section these days. The FVP5 is single-ended and the RTP3D is balanced. So far as I know he has not messed around with an LCR equalization stage. I've never heard the RTP3D or later version per se, but based on my own results with a facsimile of its phono gain stage, I would predict it is one fabulous piece. He uses a pair of resistors between the emitter(s) of the bottom transistor(s) (MAT02 or other) in the input dual-differential cascode and the CCS to control total phono gain. (Believe me, with the MAT02, which has a Gm of 500!!!, you will have gain up the wazoo.) The FVP5 would be easiest to build and may be all one needs for great MM reproduction. Does he sell it as a kit?
axelwahl OP
788 posts
 
Lewm
>>> Does he sell it as a kit? <<<
I have actually send him an email.
I'll see what comes back.
Thanks for the feedback also.
Axel
lewm
13,204 posts
 
I see no mention of an FVP kit on the Vacuum State website. I do see mention of a new phono stage, the SVP2, but it is rather costly for use as a dedicated MM phono section. Has anyone heard the JLT1? The price is acceptable, but I know nothing about how it sounds.
axelwahl OP
788 posts
 
Hi Lewm,
following FYI, (in answer to my query to A.W.):
>>> The balanced phono stage with "floating" RIAA is not usable as a stand alone unit, as it cannot drive a interconnect cable, and requires a fixed 50k ohm loading to have correct RIAA eq. <<<

And:>>> What is your favorite MM cartridge? <<<

Well, I tried to answer that, and even with the few MMs I have it is not so easy to tell. Right now I've switched to a 'Townshend Elite EEI 500 (parabolic)' and it immediately shows, it can do punchy bass and pretty clean treble.

So now, what's your favourite MM cart?

It'd be just interesting to hear, since I've buried the SUT for the moment :-)

Axel
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