Improve the sound of my CD Player?


I have a Marantz 67SE going to my Lexicon DC1, I’m using the digital out because the DC1 converts everything to digital anyway. From what I’ve read here, and other places, I should do other things first before getting a new transport. This is where I am looking for help, what can I do to improve the sound of my system – short of replacing the DC1, (don’t want to spend that kind of money yet). If I get an inexpensive DAC I assume I will have to have the analog output go to my amps (Monarchy Deluxe 100) because sending it to the DC1 will defeat the purpose of the DAC. If I do this I would guess the DAC would have to have a volume control. I do not have much experience with 2 channel so any suggestions would be very much appreciated.

Thanks,
Phil
pj5648
Ljgj...thanks for your answer...one more question.. do you know what the difference is between the $99 taddeo on their web page and the $49 Acoustic Research "TDS" device for sale at audio advisor?
I went to the Audio Advisor site and did not see any device by Audio Research of a similar nature. If you are referring to the TDS unit that changes the harmonics and comes in two versions - I am familiar with the TDS Audiophile version. I owned one. It does give you a definite night and day difference in sound but not all for the better in my opinion. It also introduces noise into the system by boosting various frequency levels to bring forward a brighter and more forward sound that I am sure some people may like. I did not.
I went to the Audio Advisor site and did not see any device by Audio Research of a similar nature. If you are referring to the TDS unit that changes the harmonics and comes in two versions - I am familiar with the TDS Audiophile version. I owned one. It does give you a definite night and day difference in sound but not all for the better in my opinion. It also introduces noise into the system by boosting various frequency levels to bring forward a brighter and more forward sound that I am sure some people may like. I did not.
Ljgj--Acoustic Research,,,not Audio Research, but thanks--and I think I am confused--I figured TDS and Taddeo were the same company or process, but you distinguish between the two. So it was the Acoustic Research TDS unit at Audio Advisor that I was asking you about and if I am getting this right (I hope!) you are saying TDS and Taddeo are not the same thing, and Taddeo is good (basically) and TDS is a mixed bag. Thanks for the clarification and saving me a mistaken purchase!
Sorry - yes it is a newer version of the TDS unit I had. it will definitely make a huge sound difference in your system than the Taddeo. You may like it - I thought it did too much messing with the frequency curve for my taste. It use to sell for 199 and 350 I believe in another double version. For 49 it may appeal to you if you can send it back if it doesn't. The taddeo is a lot more tame.