Looking for the best MC-Amp (to my ears)!

[Audiofanatic]

I'm looking for the best phono amp (to my ears) to build and I realize that my taste/choice is not the same as you guys or perhaps it is? But to tell you the truth, I'v tryed these and still didn't find the one that makes me happy.
-ONO
-Pearl
-Spectral DMC 12
-Krell KRC and KPE
-Audio&Techniek Tube DIY MM stage with the SUN AUDIO SAT-1000 Transformer.

The one I'm using now is the PLINIUS M14 (from a friend) and to be honest I like the softness of the Pearl the most. But it does not reach the deep bass of the Plinius M14.

Frank, or an other forum member, can you help me?

I want to try the Tube MC Headamp Frank sheared with us, with the Plinius on MM. What do you think of this combination?

I have the Delphi MK III with the IKEDA tonearm and the Shelter 901 MC.

I hope It's not confusing to you guys.


Thank you very much.


Best regards,


Audiofanatic

[Notorious]

I have Audio Research SP-11 and I'll never part with it.. But while my SP-11 was on service, I could borrow SP-10 which is full valve amp, and I thought when, and if my SP-11 ever gives up on me, I'll buy SP-10. It's an old amp, but a true beauty.. Really great thing..

[analog_sa]

I want to try the Tube MC Headamp Frank sheared with us, with the Plinius on MM. What do you think of this combination

An interesting question is whether the MC input in the Plinius is an add-on (like in Ono) or the gain of the entire phono is switchable. In the former case it will, indeed make sense to use a separate tube pre-pre.

The best types of phono preamps to my ears are variations of the Arthur Loesch circuit - 3 stages with split passive RIAA with separate PS for each stage. A very high quality transformer (amorphous or nickel) may be even better than an active MC input stage.

I am curious about the Allen Wright circuits - a different and interesting approach.

Does your assessment infer that the Pearl is superior to the Ono?

[Audiofanatic]

Hi,

I'm Just saying that I like the sound to be tubeee!

The Ono sounds (again, to my ears,) to analitical
The Pearl sounds smoother more natural and yet not so tight in the lower region. Am I asking to much?

I want a combination of both world. Is this posible?

Best regards,

Audiofanatic

P.S. the PLINIUS has no ad on stage, but can be done by soldering the tube input on the boards MM input.

[analog_sa]

PLINIUS has no ad on stage

In this case you may or may not experience an improvement using an additional tube stage as you are effectively complicating the signal path. As i am deeply suspicious of the concept of smoothness ( it seems to imply less resolution) i don't have further suggestions. Ime tubes bring 'smoothness' only when improperly applied.

regards

[Upupa Epops]

topology is three independet ams topology with split RIAA correction - I very agree with analog_sa . This topology : first amp - tau 1 + tau 2 - second amp - tau 3 - output amp is realy the best in listening test and very good with noise. As first amp you may to use AD 745 or any goog opamp with differential input maded with 2SK170 or 2SK147, certainly in this case for MM. For MC you must use "pre - pre " with AD 797 or to use good step up transformer - again I agree with analog_sa .

[fdegrove]

Hi,

Ime tubes bring 'smoothness' only when improperly applied.

And I'd second that one hundred percent.

In case Audiofanatic wants to go valves all the way, I'm most willing to help out....

Cheers,

[Panelhead]

If you like the sound of the Pearl, why not add a gain stage to the input. Several others have done it with good results. The input stage of the Pearl is a great circuit to start with.
Mine is a pair of matched 2SK170BL, each sitting on a 22 ohm resistor. The pair is cascoded with a ZTX450.
Power comes off the Q5 second regulator of the Pearl. Through a 10 mH choke, 1000 ufd cap, then 700 ohm resitor to the ZTX450. The output is cap coupled with a 1 ufd stacked film and foil cap into the 47K input of the Pearl. The board fits right in the back of the case.
The sound is much better than it was running a pair of AN UK step up transformers. I think the MC stepups work better with tube phono than with solid state. I think it has to do with drive current. When you step up the voltage, the current gets stepped down. The resulting current cannot drive the combined gate capacitance of the 4 2SK170BL in the Pearl.

George

[Audiofanatic]

Originally posted by fdegrove
Hi,



And I'd second that one hundred percent.

In case Audiofanatic wants to go valves all the way, I'm most willing to help out....

Cheers,

Hi Frank,

I may go for a tube, but only in the Head amp. Not the full amp.

If you think you can convince me to go full tube, send me a private mail to convince me.


Best regards,


Audiofanatic


Welterusten, late again!

[Saurav]

I think the MC stepups work better with tube phono than with solid state. I think it has to do with drive current. When you step up the voltage, the current gets stepped down. The resulting current cannot drive the combined gate capacitance of the 4 2SK170BL in the Pearl.

OK, this has been bugging me all weekend long So how does one go about determining this? I have a Pearl, and I added input transformers to the chassis. I think mine are set up for 1:10 voltage gain (or current step-down). I tried finding datasheets for the 2SK170 transistors, and it looks like they have 30pF input capacitance? Could someone confirm that? The Pearl uses 4 of these in parallel, so that's 120pF. Which is pretty darn high, I think.

So how does one determine whether a specific cartridge, when its current has been stepped down a specific amount, is good enough to drive this capacitance? It boils down to a tradeoff between the reduced current drive with the transformer vs. the increased noise with an active head amp stage, right. Though if you can keep your noise below the surface noise of the vinyl then it doesn't matter...

120pF, 20KHz, 2.5mV, I can calculate the required slew rate from that. How do I find out how much current my cartridge is delivering?