MC phono stage without transformer?

Palasr,

The Slagle autoformers are being used for the TVC.

A post from John on his Audio Circle forum regarding the step-up transformers:

"Finally I have a new transformer I am happy with. It's a unit wound by Magnequest that we worked on together over a good part of the past year. We tried quite a few options and this one really stood out from the rest and it felt good to land on something like that! Just now getting the shielding can's on order and arranging a production run with Magnequest so it'll be the end of June or so before I get the stuff needed to make the first production run.

Pricing should be the same as before - or very close. The 1:10 / 1:20 gain switch will be standard now."

He had a couple at VSAC so he is probably very close to full production.

Ralph is absolutely correct in that transformers have their problems. Designing one that gracefully hides their limitations is quite the challenge, with some of the main contenders being Lundahl, Bent (Slagle), Jensen, Tribute, Audio Note, et. al.

Now, designing a phono stage capable of accepting a .25mv cartridge and producing musical output is not a trivial affair either, and Atmasphere, Nick Doshi, and Essential are some of the main contenders in this arena.

I've heard entrants from both camps produce very musical results.

A while ago, I did a bypass test with a pair of Lundahl step-ups (LL 9206) into my full-function Quicksilver preamp. The Quicksilver is MM-only capable with total gain (including line stage) being 58 dB. The good news is that it is extremely quiet, and the gain structure of the rest of my system permits me to get reasonable volume when fed by my Dynavector XV-1s.

Running the Lundahl, there was the slightest bit of audible smearing, but all in all, it was remarkably close to running straight in to the Quicksilver which is a very revealing phono/pre.

Some MC capable phono stages have separate MM inputs. You would be advised to try this test yourself if you have access to one. Run a step-up into the MM stage and compare it against running straight into the MC stage.

For the price of the Lundahal (while not perfect, it is faithful to the music), you'll learn quite a bit about what may or may not work in your system context.

Also note that Jim Hagerman makes a solid-state head amp, which I believe is called the Piccolo. It's another option for those with MM-only phono stages. I've yet to try one, so I can't comment on it.

The problem you will face is in auditioning in your current system context. You may well find yourself preferring one architecture over the other, only to discover later (with an equipment swap), that your results change 180 degrees. This isn't the first time you've heard this, but in the case of analog, the number of variables you're dealing with make the analysis exponentially more difficult to sort through.

Cheers,
Thom @ Galibier

Ahh ... I missed Clio09's comment, noting that John Chapman is using Magnequest for his Bent/Mu step-ups (and not Intact Audio/Slagles). John is using Intact Audio (Dave Slagle) autoformers for his TVC however. I heard a pre-production unit over the weekend.

Sorry for the confusion.

Cheers,
Thom @ Galibier

Dan-ed, It may not be possible to avoid using load resistors with certain cart/trans. Im merely showing a resource for another solution. With some trans the cap is supposed to suppress the ringing although jensen is the only one Ive come across so far that gives precalculated networks for a given load. Ive been experimenting with a variety of trans various loading options and so far no resistor (or cap) has sounded the best but only after finding a trans that is a good match (nat imp and gain) for my cart. The search goes on. I also found that the high priced trans were not necessarily the best for a given combination. If I wasnt into experimenting and diy solutions Id just call Kevin at K&K and go with his recommendation.

Thanks, Rccc. That makes more sense, a zobel to correct load imbalance that may be contributed to ringing with some trans. I also agree that no components at all should sound the best. Good luck with your search. I've also begun to take a more DIY approach as of late, except I've started at the speaker end and am working backward.