Alt Bike Culture - Excessive bottom bracket friction

I just had a bike put together for me by a friend of mine who lives a couple hours away. Its a vintage frame that's been converted into a single speeder. I have a brand new Phil Wood bottom bracket in it, and when I ride at low speeds its incredibly smooth, like I'm riding on a cloud. When I start pedalling faster, however, I definately feel some friction coming from the bottom bracket, like its vibrating slightly. It only happens while I'm pedalling. Sometimes I think I can hear it, althougth its mostly a sensation that I feel. Its very slight, but I spent a lot of money on this bike and I feel that it should be perfect. As far as I know, the chainline is perfectly straight. Does anyone know what could possibly be causing the bottom bracket to vibrate, or what could be causing unneccesary friction? Thanks.

Obviously, this thread was intended for the "bicycle mechanics" forum, sorry for the mix-up..

I just had a bike put together for me by a friend of mine who lives a couple hours away. Its a vintage frame that's been converted into a single speeder. I have a brand new Phil Wood bottom bracket in it, and when I ride at low speeds its incredibly smooth, like I'm riding on a cloud. When I start pedalling faster, however, I definately feel some friction coming from the bottom bracket, like its vibrating slightly. It only happens while I'm pedalling. Sometimes I think I can hear it, althougth its mostly a sensation that I feel. Its very slight, but I spent a lot of money on this bike and I feel that it should be perfect. As far as I know, the chainline is perfectly straight. Does anyone know what could possibly be causing the bottom bracket to vibrate, or what could be causing unneccesary friction? Thanks.
If the cups of the Phil Wood bottom bracket are over-tightened, they will feel gritty, or feel like it is turning hard(er).

Since I don't have a Phil Wood tool, I took the bike to a few bike shops hoping that they would have one. I explained the situation and suggested that maybe the cups were overtightened. Two shops said that with a sealed cartridge that is impossible, although they also admitted little to no expirience with a Phil Wood, so I don't completely trust them. I then took the bike to Urbane in Toronto, and they don't think its the BB at all, rather they just think I need some grease in the crank bolts and chainrings, or something to that degree. Hopefully that will help, if not, perhaps I should order a new Phil tool and try to re-adjust the cups myself. Thanks for the advice.