Do I need a preamplifier

Some say the less the better. Do I really need a preamp if my power amp has a vol poti? i.e. go straight into the poweramp from my source. Seems to work well my cd player. Would like to the same with my phono stage using a switching box to switch between the 2 sources.
Depends completely on the quality of the potentiometer in your amp. You should probably try to demo a couple of preamps and compare.
The Creek 22 passive preamp has remote volume and switching and a very good reputation for about $500.
CIaudio makes a nice one for $300.00.I was thinking going that route.
a preamp contributes to the voicing of a stereo system.

listen to some preamps and note the change in the spectral balance. you may or may not prefer the change.
Thanks folks. I have an OTL Eternal Arts amplifier and have a switch box. So you state Mrtennis that a pre will change the spectral balance. Is there any chance that the soundstage will improve as this seems to be only thing lacking? otherwise i will get a good phono pre perhaps tube if I can find a quiet one.Any suggestions?
If you don't need the added functionality that a full-function preamp would provide (tape outputs, balance control, mono switch, etc.), my feeling would be that you don't need one.

If your power amp includes a volume control, it essentially incorporates a preamp function, apart from source switching and those other functions. While the possibility exists that adding an active preamp would produce a subjectively more pleasing sound, that would be, if it occurred, the result of euphonic coloration that was masking problems elsewhere, and that would be better addressed elsewhere.

-- Al
You have it right, Al. IF your CD player output stage is up to driving an amp directly and IF your amp has proper impedance etc. then you will get the most accurate, purest sound this way. But not everybody likes it. A friend of mine agrees with this but adds a tube preamp because he likes the euphonic coloration this particular unit adds. I can see the preamp altering the sound stage but it is harder to see how it will supply what isn't there in the first place. It may spread the sound out to give an illusion of more separation but it will be an illusion. In the review of the Creek I mentioned above the reviewer compared it to his own preamp, a modified SP 10. One of his amps did not work well with the passive but on the two that did he noticed an interesting effect. On one amp the two were very similar but the SP 10 appeared to be slightly fuller in the bottom. When he listened just to this range he discovered that the SP 10 was filling up the space between the notes that the Creek was leaving empty. On the other amp he tried the Creek was noticeably cleaner. The moral is, try it and see if you like it. Keep the cable between the CD and amp as short as possible. If I has soundstage problems I would try some different cables. This afternoon a friend of mine and I were listening to his system and substituted 4 different cables between the transport and DAC. The difference was striking. They sounded quite different. We were using Cardas, Van den Hul, Wyde-eye and another of his. The sound stage moved forward and backward to a suppriseing degree. Although we disagreed about which we liked we were able to agree on what each was doing. I would try using different cables rather than trying to find a preamp to correct the problem.
Thanks folks. Will continue without. Receiving my Kuzma/313 player today and am considering getting the Naim Superline / hi-cap phono stage , perhaps a koetsu red cartridge, alternatively the Benz LP.