[felixscerri]

G'day all, and a Happy New Year all round!  You know I guess that I'm mostly thinking out loud here but the best and the worst thing about playing records is the 'complexity of it all', and sometimes getting the little and seemingly inconsequential things right can make the world of difference!  Yes it's true. 

Whilst the (OEM stylus) Shure M97xE has been my favourite phono cartridge for many years, it has taken me quite a while to get it working 'just so', and it's taken a little synergy as it were, to do it! 

I've built a simple DIY phono stage that for some reason works superbly with the M97xE for reasons that make no real sense, but work well....it does! 

This simple DIY phono stage that I built only for typical high output moving magnet cartridges:  http://diyaudioprojects.com/Chip/Opamp-Phono-Preamp/  Although it is a simple full feedback op amp based design, it sounds tremendous and seems perfect for the OPA2134 dual op amp.  I've 'rolled' a few different dual op amps in the design including the LM4562 and none perform as well as the OPA2134 (including noise figure)!

The 'finishing touch' with the Shure M97xE is of course electrical loading, and 47 k loading is fine but the value of loading capacitance is critical!  Having a good capacitance meter is a very useful piece of test gear to have and having 47 k with 280 picofarads (total 'overall') capacitance loading sounds superb and 'musical'.  250 to 300 picofarads is about the optimum range of loading capacitance in my observation.  Sometimes yes it takes a while to get it right, but persevere!  It's worth it!  Regards, Felix.     

[neobop]

Happy new year Felix,
Thanks for posting a link to your favorite.  No more 62K load?

Wondering if you've come across a DIY LCR phono, one that uses an inductor in the RIAA EQ circuit? 
The only DIY one I've seen uses tubes. 
neo

[felixscerri]

G'day mate, yes 62 k does certainly extend the upper treble but is essentially 'impractical' to implement as it were, unless one is DIYing.  In any case 47 k at 250 to 300 picofarads is what Shure intended with its 'Audiophile Response Curve'.  This optimum value of capacitance loading also applies to 62 k loading as without it a very audible midrange droop develops. 

One Shure curiosity though is the Shure recommended load capacitance range is 47 k at 200 to 300 picofarads, which is way too broad in my opinion.  250 to 300 picofarads (in total) is indeed optimum and I think that all record playing people should have a good capacitance meter, and learn how to use it!   

On the LCR designs well I have the Lounge Audio LCR MKIII phono stage which is excellent!  It is not a DIY unit and uses an LCR RIAA network in conjunction with high speed op amps.  Regards, Felix.