Tube Buffer


Despite using balanced XLR output from DAC to Peachtree Grand Pre, I find digital harshness remains until I engage the Peachtree's dual 12AU7 tube buffer section. However, the Grand Pre sucks as an analog preamp and needs replacing for that reason. I love the functionality of the Musical Fidelity M8Pre, which also has a good phono section, but I fear that as a solid state device it will simply pass the harshness down the chain. Rogue Audio RP7 is a tube preamp which would presumably kill any digital glare, but has no phono stage. The Rogue RP5 is a lesser device overall, but does include a phono stage plus, of course, tubes. Questions: (1) sonically, how much better is the RP7 than the RP5 (considerably, according to TAS)? (2) Does there exist some relatively inexpensive tube buffer device which can be placed between DAC and the solid state M8Pre? Really not in the market for an outboard $2k phono preamp.
hickamore
I owned a Rogue RP-5 tube preamp and it is a great preamp. The phono section is very versatile and TAS also LOVED the RP-5 which they tested a couple of years ago. Unless you run all balanced, I see no reason to get the RP-7. I had great results changing out the 4 JJ stock tubes with Mullard CV4003 tubes per recommendation of Rogue. The preamp was always dead quiet, even with the Mullard NOS tubes. It is a very musical preamp and it even has a remote.

The problem is the Peachtree Audio you have.  My friend had the 225wpc integrated and it sounded cold and harsh unless he used the tube buffer output.   He ended up trading it for something else but I don't know what he bought.
Maybe I missed it but what power amplifier are you using? Aside from the general tube "warmth", what you might be experiencing is an impedance mismatch between the preamp output and the amplifier input and engaging the tube buffer could possibly correct this potential mismatch. Do you know what is the preamp output impedance with and without the tube buffer and the amplifier input impedance?
Just a thought... 
tomic, stereo5, kalali, many thanks for sharing your knowledge.

I'm pleased to know the Rogue RP5 beats the Peachtree sonically. I had been thinking more of functionality, but this is more than a bonus. And I will never quite be ALL balanced in the RP7 or Musical Fidelity M8Pre sense.

Impedance mismatch with Parasound Halo A21 power amp had occurred to me, but I haven't the technical knowledge to verify one way or the other. Parasound disclose the input impedance. Peachtree out, with/without tubes, I don't think so. How do you suppose the RP5 would match up with the Parasound?
uber, what a find! Will definitely check this out. At last a wager one could afford to lose. Thank you.