A comparable phono preamp

If you are willing to stay with MM or moving iron you could not too much better than an Audio Research LP 1 which you will have to pick up used unless there is a NIB to be found somewhere. I use one in one of my systems and it is exceptional for the cost. Look it up.

+1 for Rogue Ares. Very flexible due to wide scale of gain adjustments and tube rolling friendly. Outboard linear PS. If you lucky enough you could get upgraded Magnum version of Ares for around $1500 used. 

@avanti1960 1++  You are probably overloading the NAD which would result in the sound you describe. You really do not want a MM cartridge output higher than 5 mv. Avanti's suggestions are fine but probably more expensive than you would like. It would be less expensive to go for something like a Parasound JC3+ and a lower output cartridge like one of the high output Soundsmiths which put out about 3 mv. 

Take a look at what Darlington Labs has to offer. MP7/SU7 combo starting at $1000. Read what people are saying. I've been very pleased with my MP7 and Keith is great to work with!! Not upgrading any time soon...

I highly recommend the Sutherland offerings. They have models to meet a variety of budgets and provide tremendous value with wide range of impedence and gain adjustments. 

As avanti mentioned is appears that you may need lower gain capability with the HIGH OUPUT Linn cartridge.

If you are interested in an inexpensive stop gap (while maintaining use of the Linn cartridge) you might look @ the Schiit Mani-2 phono preamp (make certain it's the updated "2" version).

It's well reviewed, gain can be set as low as the mid 30's (to see if this is the problem) and it's $150.

You could also compare it to your current phono pre in regard to analog/digital transfer.

The last tube phono preamps I tried in my meager setup were an Audion Sterling and an EAR 834P (MM only), so I'm not up to date on what's good now and/or what models have user adjustable gain.

DeKay

I would need to spend 10 to 12000 and would rather spend that on better interconnects and speakers.

Hmm, better cabling obviously makes a difference BUT strongly feel that a primary upgrade ( table /arm /cart / phono ) will be a better investment in this case, as described...

As for budget I am not sure 2000 to 3000 for a phono preamp and maybe tube to match the tube preamp I went with the rogue rp7 because of its outstanding  sound it was equal to preamps twice its price. I may upgrade the amp to a tube amp at some time there is something about tube. Other then a better cartridge I am not going to upgrade the turntable. I been told by many that to improve my turntable and notice the difference I would need to spend 10 to 12000 and would rather spend that on better interconnects and speakers.

In the UK, I have been at an event where the Modwright PH 9.0 ’SE’ was demonstrated in a line up along side a broad selection of Valve and SS Design Phonostages.

This is the Fullest / Warmest SQ, I have heard in the past 10 years + , where there is still a perception present that the Bottom End is not muddy or bloomed.

The Speakers used at the event were over $100 000 to purchase.

It is difficult to project if the same experience is to be perceived in other systems, it might be best if an investigative trial could be arranged.

I only mention this model, as I know it relatively easy to come by in the US.

I’ve had turntables for over 50 years. As I upgraded my components, it became increasingly clear that the phono stage was a critical component. I tried inexpensive Phonostage after Phonostage, slowly increasing the cost (used at first). My rule of thumb now is, one should invest as much in a phono stage as a preamp, amp, streamer or turntable… a generality.

Depending on your long term goals of your system. If your long term intent is to build ever better versions of your system… then it will best suit you to get a very good Phonostage now. This will allow you to hear the best your TT and cartridge have to offer. If you are just shooting for something comparable with your current TT and future cartridge budget that amount.

I recommend Audio Research (alternatively Conrad Johnson, or VAC). The Audio Research is very detailed without being hard, great midrange bloom, complimenting the vinyl playback media. My highest recommendation would be a used ARC PH8. To me it is the sweet spot of cost and outstanding performance. I owned many models before and after. I now own a REF3. If you cannot afford that drop back to a PH6 or PH7. They have great resale value, are audio-hill grade equipment and are highly reliable. But of course you buy for the sound quality. 

Budgie for sweet 

Puffin for totally adjustable.

Not sure if I'd call MC an "update"

Different for sure.

Your Adikt cartridge has a 6.5mv output which is 30 to 60% higher than typical MM cartridges.   You need a phono preamp that has low enough gain to avoid conditions which sound as you are describing with your NAD.  

The typical gain for your cartridge by the book is 34 db. Very few preamps have gain this low- most begin around 40db of gain which could be too much.  

The Luxman E250 has 38db gain for MM which should be fine.  

The Chord Huei has user adjustable gain from 25 db to 35 db which should also be fine.

Both are of very high sound and manufacturing quality.  

"phono preamp that will give me that warm natural sound"

It's a no brainer to include the Rogue Ares in your search.

 You will get suggestions all over the map, stating this is "better" or over that, but you know it's a subjective thing in the end.

http://rogueaudio.com/Products_phonopreamps.htm

@mal11963 what's your price range? Looking for ss or tubes?