Perhaps the 600 ohm "standard" stems from the pro side when making records in applying RIAA EQ, which was made using LCR network, inverse curve of course.
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LCR phono stages we know about
Lately, I have become enthralled with LCR phono stages, based on some personal listening experiences and on the fact that many designers I respect are involved in LCR phono design. However, I don't really feel that I have a complete picture re what's out there in terms of commercial products. If you own or have heard an LCR phono stage and have an opinion, please name the product and feel free to render an opinion of it, compared to other phono stages of any type with which you are familiar. Thanks.
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Good point. That's where Dave Slagle jumped in, to design and build chokes that will work well in "high-impedance" LCR designs. Dave can create very precise modules. One of our readers has done a little digging into the Emia phono stage. Apparently it is NOT an LCR type. Rather, it is a novel CR type wherein the high value resistor(s) in the signal path have been eliminated. In fact, my correspondent says he was told that there are NO R's or C's in the series signal path between the input stage and the output stage; All Rs and Cs are shunted to ground. (I am only the messenger here.) Thus the plate of the input tube is direct-coupled to the grid of the output tube, with all the filter components shunting to ground. I can only say it sounds great, no matter what the topology. But I really do not know how one can avoid having either an R or a C in the series signal path and still get to proper RIAA equalization. On the other hand, the two designers are smarter than I. |
Hi Lewm, Nearly a year back, we did a phono shootout, including a Thomas Mayer LCR phono, please see some of the write up in the following thread (mainly in the 2nd and 3rd page from the most recent) http://www.1pekingroad.com/zaspx/replies.aspx?PageNo=2&topicsno=4&subjectno=1849&uppersubjectno=1849&sortby=updatedate&orderby=desc |
Thekong, Thanks for mentioning the Thomas Mayer LCR phono stages. I had been meaning to do so as well. He seems to sell an LCR phono in kit form, using Dave Slagle LCR modules (aka "Intactaudio"). Very tempting. As to this shoot-out, it is not very helpful, although it seems the participants were having great fun. For one thing, several different SUTs were used with the Mayer LCR; I think the SUT will a major effect on sonics, if not THE major effect. I am somewhat familiar with the Scott Frankland phono stage mentioned. IMO, it is good but not a contender among today's best options. But you've added Thomas Mayer to our list. I wonder what he charges for that kit version? |
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