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No. 26 - MM or MC board?

Hi - I am trying a ML 26 preamp w/phono stage in my system, (Denon 103R cart.). I set the gain internal switch to 58dB or 38db and cartridge gain to 100 Ohms which I beleive is the recommended load for the Denon (instruction come in Japanesse so I can´t tell).

The point is that eventhough sound level is acceptable at the 1 o´clock position in the volume knob, there is not enough dynamics compared to the line level input (CDP in this case) and far from my previous Michael Yee phono preamp signal.

Could it be that this particular No. 26 has a MM board?
The 100 ohm setting is wrong for the Danon 103r?

Thanks for sharing your experience and knowledge here.

Fernando
flg2001
twl
3,251 posts
 
100 ohms is a fine place to start the loading on the phono stage for a Denon 103R.
You might do some experimenting with + or- about 20% from there, to see how you like it.

It sounds to me like the phono gain is a little bit low, based on your description of lacking dynamics. The 103R has an output of about 0.27mv, so it needs plenty of gain in the front end. Unless your linestage has about 25db of gain, then I think the available 58db setting on the Levinson is a bit too low for best performance with that cartridge.
flg2001's avatar
flg2001 OP
543 posts
 
Thanks to Michael and Twl. I will check the links provided.

I also have an unused passive stepup transformer (cotter I believe) which may plug in to see if I get a better reproduction in terms of dynamics.

Twl: If it is a MC board what I have in the 26, then it would be a 38dB gain setting, which is not in the 25dB you mention but closer to the 58dB if it is a MM board.

Fernando
twl
3,251 posts
 
The higher gain is the MC board, and the lower gain is the MM board. The 38db or 58db relates to phono section gain only, and the linestage also has a gain figure(typically between 10db-20db). The phono gain and the linestage gain are added together to get total gain in the front end.

If you add in the step-up transformer, it will also be added into the front end gain. I've found that the total front end gain with the DL103R is good at about 80db total front end gain. My system has a Cotter step-up(20db), 46db phono gain, and 20db linestage gain, for a total front end gain of 86db. This worked out very well for me when I was using the DL103R in my system.

Remember, that when you use a step up transformer, you load the cartridge AT THE TRANSFORMER at half the normal amount(40-50 ohms) instead of the 100 ohms. You then use the normal 47k loading at the phono section input. The Cotter is difficult to adjust loading on(soldering jumpers), so I hope that the one you have is the "Type S" version of the Cotter Mk2 tranny.
flg2001's avatar
flg2001 OP
543 posts
 
Thanks Twl, very important advise from you that I will surely consider, specially the added load settings using the step-up.

I will let you know how it sounds with and without the step-up, taking into consideration that the current 100ohm setting is OK for the Denon if feeding directly to the No. 26.

Fernando
rauliruegas
9,123 posts
 
Dear Fernando: The name of Mark Levinson was constructed around their power amplifiers not for their pre-amps and certanelly never for the phono preamp. The 26 is not a good phono preamp. My advise is that you stay aways of that ML 26.

BTW, while you insist with the 103R you will be out of the game named: " analog sound quality reproduction ". You can't do nothing about with that cartridge. Please grow-up, you can do it.

Regards and enjoy the music.
Raul.
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