Preamp for NADC370,please

Hi,I have been looking for a preamp(around 600$)in replacing the preamp section of my NADC370 Integrated amp;expecting for sonic upgrade(softer highs,heavier bass).
My systems (1)AhTjoeb4000 CDP;(2)Quadral Ascent850 spkr;(3)Analysis Plus Oval 9 spkr cable;(4)TruthLink-IC(harmonic tech).Your opinion and suggestions is highly appreciated and thanks a lot
The C370 is a nice piece for the $. Do a foreplay kit at $150 basic and about $300 w/ mods or a "Bassie" kit at for a few buck more. Both are easy DIY kits that will get you better sound than retail and one learns a lot too. Lots of folk like tube pres.

Good luck
I remain,
While I have not heard the C370, I recently bought the C350. Nice sound for the money, but not good enough for me. I had already tried a more expensive ss integrated amp and that didn't cut it either. Since I had already sold my preamp (this was a downsizing exercise), I figured I would use the preamp section of the NAD for awhile. Not wanting to spend a lot because I do not listen to this particular system much, I bought one of those 80 watt AMC tube amps you see auctioned here and on ebay. I got a significant improvement in the sound. Bass was a little deeper, but not as tight. However, the midrange of the AMC is in another league compared to the NAD and just about any other ss amp I have heard under $2k. The AMC does not have as soft a high end as some other all tube amps (it is a hybrid design) so it may not work for you, but I think it is an excellent value and worth investigating. A tube preamp may also help you, but I am not sure what will yield the most bang for the buck.
How about Parasound H-PH 850 or Musical Fidelity X-PRE ? which one is better match with the NADC370 ? Once again,your opinion and suggestions is highly appreciated and thanks a lot
Simon: Did you ever replace/upgrade the jumpers on the 370? If not, then I would try this first (as it is a weak link). Commercial reviews of the X-Pre state that it really needs the addition of the MF X-PSU to perform well. This has been said of all the X-gear that uses the little stock wall wart, for a power supply, and makes sense. Also what tubes are you running in the CD player? This could be another possible upgrade? Based on your goals of "softer HF's and fuller bass", certain 6dj8/6922/7308 type tubes can supply this sound and some not. Smooth HF's suggests tubes from the Amperex/Philips/Mullard group with Amperex white label USA's being my favorite all around tube (6922 or 7308 - both are good).
Thanks Dekay for your info. BTW,I have replaced the jumper of my NADC370 with TruthLink IC(same IC I used for CDP connection, only half-shorter,0.5 m).Do you think replacing the JAN Philips 6922 stock tubes of the CDP with Amperex 7308 would do it(softer highs,heavier bass)? It seemed that there is no sense of using MF-X PRE without pairing it with the X-PSU is'nt it ? The ads of Parasound HP850 preamp stated that it is supplied with 1900 uf cap?? so that it would deliver extensive punchy bass,I wonder if this is true?? Perhaps you and any one might comment on this and thanks
After spending some more time listening to the preamp section of the NAD C350 into the AMC tube amp, I am starting to think the NAD's preamp section is a bit rough and electronic sounding. I am either going to get some mellow interconnects (I am using revealing ones at the moment) or another preamp. While a good tube preamp will probably give you the best sound, I used to own a Classe DR-4 which was a very rich sounding piece, better than at least one hybrid tube preamp (Audio Note Zero) that I compared it to and certainly better than the NAD. A used DR-4 should be in your price range and will likely be better than the Parasound or the X-Cans.