I agree with the above that the 850/86x are much better than 830. Can't comment on the 831.
With regards to direct connection, I had a 850 connected to a BAT VK200, then a BAT VK60. Loved it. Then my dealer talked my into bringing a BAT VK50SE preamp home. Huge improvement. everywhere. So, on a cost basis, the Wadia smokes it directly connected IMO. On a absolute basis, a really good preamp is better.
At the same time I added a turntable and another source, so the preamp was needed there...however, if you have the $$'s try one on the wadia...
With regards to direct connection, I had a 850 connected to a BAT VK200, then a BAT VK60. Loved it. Then my dealer talked my into bringing a BAT VK50SE preamp home. Huge improvement. everywhere. So, on a cost basis, the Wadia smokes it directly connected IMO. On a absolute basis, a really good preamp is better.
At the same time I added a turntable and another source, so the preamp was needed there...however, if you have the $$'s try one on the wadia...