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.
lewm
Jazdom, Hi. Can you say more about the Kahn phono stage. I presume the name refers to our mutual friend in Silver Spring. But maybe not.
John, I own a Silvaweld phono stage, designed and produced by the same Mr. Park who later went on to produce the Allnic products. He evidently had a huge change of heart after Silvaweld went under. Silvaweld phono stages are all RC types, use a capacitor as the first element in the filter, thus avoiding high value resistors at that point in the signal path (or any resistor, for that matter). However, using a capacitor has it's own theoretical issues, since capacitors are also imperfect devices; one might say they are more imperfect than resistors in fact. So the Silvaweld circuit is a far cry from the LCR used in the Allnic H3000 (or H1500). The Silvaweld also uses a JFET input to add gain for MC cartridges, followed by an all-tube RIAA correction network that by itself develops sufficient gain for any MM. In contrast, Allnic phonos use built-in SUTs for this purpose. I use my SWH550 only for MM cartridges, so I bypassed the JFET permanently, and then I rather drastically modified the tube circuit downstream, with some help and advice from a more knowledgeable DIYer. (Kept the capacitor-led RIAA as is.) The result is shockingly good. I have a neighbor up the street who just got hold of a LCR MM made by Dave Slagle and his business partner. I do not know the commercial name. I heard that the other day and am VERY impressed. I am familiar with my neighbor's system and had heard it previously with two other very good phono stages, Coincident and Dolshi. By comparison, the Slagle unit sounded very open, airy, effortless. He's made some other changes in his system along the way, so one cannot attribute all of the improvement to the new phono stage, and I would not say that the new phono "kills" the previous two, but.... it's very beguiling.

So, here's a list of some of the LCR phonos mentioned above:
Allnic H3000, H5000 (not a real-world possibility for me), H1500
Lounge
"Kahn" Experience Music
Ypsilon
Zanden (did not previously know that was an LCR type)

I know there are others in between the extremes of cost ($32K for the H5000 vs $250 for the Lounge [maybe the Ypsilon is even more costly than the H5000]), but my mind has gone blank. The Dave Slagle design costs ca $5000, plus the cost of any added SUT for MC. There's another one available via eBay from the orient that has received favorable mention. I am really curious about the H3000 and am on the look-out for a used one.

For the really far out theoreticians, I have read about LR-based RIAA filters, which use no capacitors at all. Apparently that's very tricky to execute because the values of the inductors must be very precise in order to achieve good RIAA compliance.
Addendum. After composing that long treatise, I did some surfing to find out more about the Slagle LCR phono stage owned by my neighbor. It turns out that the phono stage is called "Emia" and is marketed by Dave and Jeffrey Jackson, in collaboration.
Here

Further, the "Kahn" Experience phono stage is also a product of this same collaboration, only it's more expensive than the Emia.

So these two would be important players in the LCR game, albeit hardly mass-market.
Lew, the Vida Aurorasound has received a bit of attention in Asian markets. Reportedly around $5K. I have not seen or heard it at the shows.
Dave, I looked it up. Not much info regarding the innards. Seems to be solid state. Does not seem to have adjustment for load R and C. However, it does have a mono switch. (I don't know how you can build a phono stage with high end pretensions and not include a mono switch.) As you know, I'm partial to tubes, but I'd like to hear this one. Do you have direct knowledge?

Audio Note UK also makes few models of phono preamps that employ LCR network.

Typical LCR network is sandwiched between two gain stages with the first stage being able to drive low input imepedance, typically 600 ohms like the Tango circuit, so a cathode follower is often employed and some purists might argue against it. But who cares... whatever works and whatever sounds good.

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