I just got a new Series 2 and have the same problem with the configuration you have.
No cable box, 2-way splitter, one to TV one to TiVo. TiVo back to TV using sVideo and/or RCA video output. TV is fine video quality, menus from TiVo on TV look stunning. LiveTV from TiVo looks bad. I tried called TiVo tech support. After trying a bunch of things I now have cable going into TiVo and using RF/coax to go back to TV (not the way I want things set up) but the video quality on live TV going through the TiVo is as good as it was before.
I told the customer service rep (nicely) that if the video coming out of the sVideo/RCA video out was crappy then I thought my TiVo was not working properly and should be replaced (BTW I bought a refurbed unit from TiVo to save $50, maybe a mistake). If the video-out was crappy then anything I would want to copy to a VCR or DV camcorder or to my PC would be crappy.
I was escallated to a CSI (some more senior support engineer) who basically told me that he thought that it was a cable signal problem. He claimed that the sVideo/RCA output was less forgiving to a poor signal. I'm pretty technical and know how graphics/video systems work an this seems a little suspect to me but I have given in so far and just ordered an Electroline EDA 2400 XSP on Ebay
from CableTV Amps (search Electroline splitter on eBay since this dang text editor won't let me even spell out a url!). This is the amplifier from the same company that Comcast uses.
I have 4 cable runs coming off of a RadioShack splitter right now where the cable comes into the house and the TiVo is as the end of the longest run with several splitters along the way so I figure for $60 this can't hurt. I will also probably run a new line from the amplifier directly to the TiVo. I also have a cable modem coming off of the splitter and it works fine - I don't want to mess that up.
Has anyone else experienced this discrpency of video quality when using a coax connection vs. s-video/rca video output? Does the CSI's explanation make sense. Aren't the video out ports on a different DAC then the coax?
I would really like to use my old configuration.
Also, any recommendations on the best cable to use to run from the amp to the TiVo? It is about 50 ft.
Thanks,
MJKBoston