Solid State replacement for AI Modulus 3A.

Why don't you try a few different tubes(brands) if you haven't already. They make a bigger difference in sound quality than most tube preamps. I have used two of these preamps and never have felt they were lacking in detail and certainly not in resolution. I have compared these to some pricey preamps and went back to the Modulus. Are you using the tape in or aux for your cd source (not the cd in?)
I also will say this (and I'm not trying to knock your CD player) but the Arcam can be beat in exactly the areas you suggest. Have you tried different CD players just to see if you hear a difference?
I just don't think you will come close to bettering the Modulus in this price category. You will get some tube coloration(if you want to call it that) with any tube preamp. I have always found the CJ's to be more "Colored." (and somewhat darker) for example. I don't think the BAT lower end stuff is all that good in comparison.
Might try a passive preamp. I feel they give the best resolution,etc. for the lowest costs if it will work with your system. However, I don't feel the dynamic contrasts are as good as an active line stage.
You might take a peak at the Aleph P preamp or (ha) the Adcom GTP 750 which is a Pass design. Both pre's are musical and have high levels of resolution but you lose some of that real sweetness(musicality.)
I'm sure, as usual, you will get more suggestions. These are units I have personally lived with so I know their performance.

Read in HiFi + that Sugden Masterclass pre-amp, sound as good as any at any price. New was $3000, you might find one used for less than $2k?

Bigtee,

I am using the CD in and not the tape inputs. Can you recommend brands of the tubes you tried that you find to be excellent? Thanks.

Aaron

I recently sold an ARC LS12 that I thought was an amazing preamp for the money, not because I didn't like it but because I had to sell a whole system to make room for our new daughter. Definitely try to listen to one; they didn't get much press but are definitely a product to be reckoned with in this price range. Based on what you are looking for, I would say you would probably be ecstatic with this unit.

www.audioresearch.com/LS12.htm

Aaron, You need to switch inputs to either the tape in or aux input. The CD input has a pair of resistors in the signal path that roll the highs somewhat and are not as transparent. I personally use the tape in which appears to be a direct path. There is an appreciable difference in sound quality.
As for tubes, give Art Ferris a call. He sent me a pair of very nice sounding Sovtec's that are quiet and extremely transparent. Also, a pair of 6H23 Russian tubes from Kevin at Upscale Audio sounded extremely nice. Look on the Audible Illusions site under technical questions. Art discusses tube brands and their effect on the Modulus's sound. You also need to replace the tubes about every year if you use the pre a good bit. The usual first signs are a roll off in highs with a perceived lack in resolution and transparency with, usually, an increase in tube rush.
Lastly, if you haven't, flip the four dip switches inside the preamp to take the capacitors out of the circuit. This firms up the bass and adds to the resolution.
I'm currently uses a 01 model and have ordered a new L-2 linestage with remote. It is reported to be the best yet---we'll see. Hope this helps. Feel free to e-mail me if you have any other questions you feel I might can help you with. Phil