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-   -   Better MC Pre-Pre solution for low internal coil resistance- not only for Pearl phono (http://www.diyaudio.com/forums/pass-labs/153395-better-mc-pre-pre-solution-low-internal-coil-resistance-not-only-pearl-phono.html)

tiefbassuebertr 15th October 2009 04:35 PM

Better MC Pre-Pre solution for low internal coil resistance- not only for Pearl phono
 
1 Attachment(s)
The presently MC prepre of the Pearl phono stage (configured as high input impedance common emitter line stage with input at gate of the j-FET) is the ideal choice for MC cartridges with internal coil resistance above 100 ohms. If I have a internal coil resistance arround 15 until 40 ohms (like some models of Lyra and Audio Technica) I get better results (more tight and clear so as more sonic dymanics) with line stages in common base topology like Hiragas prepre, see
Hiraga MC Preamp
or the Mark Levinson JC1 (see pdf schematic)

what could be the reason for this?

Holger Barske 15th October 2009 08:54 PM

Disagreed. Even with low impedance sources, the Ono/XP-15 is one of the quietest phono preamps I have had my hands on.

analog_sa 15th October 2009 09:19 PM

The Hiraga circuit is a great sounding classic. Not so sure about the JC1 with the 1000uF at input.

If noise is not an issue i would take a single resistor loaded common cathode fet (or even better - a triode) instead of the Pearl arrangement.

tiefbassuebertr 16th October 2009 05:02 PM

Quote:

Originally Posted by HBarske (Post 1951020)
Disagreed. Even with low impedance sources, the Ono/XP-15 is one of the quietest phono preamps I have had my hands on.

You haven’t understand my question.
Additional I don’t know about the phono preamp “ONO/XP-15”
I know only the models
- “Aleph ONO”
- “X-ONO” (successor Aleph ONO)
- “XP-15” (currently available and successor for “X-ONO”)
Maybe you mean one of this models.

The Pearl Phono stage (not a commercial product)
http://www.passdiy.com/pdf/pearlphono.pdf
use as MC prepre a line stage in common emitter resp. source topology, i. e., a voltage controlled input. For me it is definitely clear, that MC prepre versions, which use a common base topology, that means current control input (unfortunately, very few commercial models), give better sonic quality by MC cartridges with low internal coil impedance (but I don’t know, why; and a possibility for configuration to both topologies it would be very helpful).
Because I haven’t schematic of all three mentioned models, I will not rule out, that one of the above Pass models use a prepre topology which use a common base topology (because one of the earlier preamp model of master developer Nelson Pass uses also a common base respective gate topology – see PDF file at bottom). Perhaps this is the reason of your statement.

The type number “ONO/XP-15” is total unknown for me – please send me a weblink about this, if it should really exist.

tiefbassuebertr 16th October 2009 05:04 PM

1 Attachment(s)
PDF Threshold SL-10

Holger Barske 17th October 2009 10:34 AM

Quote:

The Pearl Phono stage (not a commercial product)
http://www.passdiy.com/pdf/pearlphono.pdf
use as MC prepre a line stage in common emitter resp. source topology...
The Pearl is intended to be used with MM or high ouput MC cartridges, not with classical MC cartridges. Despite from the fact that the input stage is far from optimal for MCs (you are right on that one), overall gain is a little low for MCs.

tiefbassuebertr 1st November 2012 09:07 PM

I am looking for commercial products in the kind from post #1.
Thank you for advices.

tiefbassuebertr 7th June 2013 09:06 AM

even tube amplifiers with such topologies (GND-GRID) like that one from post #1 are present - go to the schematics from follow URL:
Teflon coupling capacitors & More No-Gain—No-Pain Tube Buffer Circuits

I know only this commercial products:

1) Audio Space Reference Two phono preamp and line stage amplifier
SoundStage! Equipment Review - Audio Space Reference Two Preamplifier (4/2008)
Audio Space Reference 2 Linestage Preamplifier | The Absolute Sound

2) Audio Research MCP33
http://www.diyaudio.com/forums/tubes...-mcp-33-a.html (go to post #4 for schematics)
REFERENCE COMPONENTS-MOVING COIL STEP-UP DEVICES

Who knows additional brands and models for MC step-up pre-preamps in this kind ?

Mr. dB 7th June 2013 06:31 PM

Didn't Nelson's preamp for Nakamichi have a common-base FET input for the MC stage?

sq225917 7th June 2013 06:49 PM

Just build a Paradise and be done with it. silent and with lots of gain.


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