No Vocals from Grateful Dead RSD LP

Hello -- this problem has me perplexed. I purchased the Grateful Dead LP on RSD and when I played it, I didn't get any vocal output. So I emailed the distributor (Rhino), which sent me another copy. I put it on last night and ... no vocals! All my other vinyl plays perfectly. My system is a Thorens 165 turntable w/Grado Sonata cartridge, Dynaco ST70 power amp, Dynaco PAS 2 preamp, Budgie phono preamp, and Dahlquist D-10 speakers. I plan on going to a record store here and they have turntables and I hope they will allow me to play the album to see if I get any vocals from another system. However, any idea/troubleshooting to find out why I"m having this the problem with this LP? Thanks!.