Reproduction of acoustic instruments with tube amp

I agree with Marakanetz. A used BAT VK60 on this site should be in your price range. Most of the music I listen to is chamber music or acoustic guitar, and they both sound great with the VK60. I don't think you can go wrong.

I too find Dburdick's findings surprising. The VTL ST-85 should be able to drive the Sparks no problem. I haven't heard the combo myself, but when I recently auditioned the new Thiel 1.6's with both my own c-j MV-55 and the store's VTL ST-85, I thought the latter was outstanding for acoustic (and electric) music, with a vast soundstage and very 3-D imaging. It did strike me as possibly a touch overripe through the midrange, but not excessively colored for enjoyment, and still quite transparent for the money. In that system (with Transparent wire), it frankly made my c-j sound small and pinched. Fortunately, the MV-55 sounds better at my place (Thiel 2.2's, Cardas Cross) - full, spacious, and neutral (and it far outshines my previous SS amps, especially with acoustic material). If in Dburdick's system the VTL didn't offer separation and definition with acoustic music, I would suspect a wire mis-match and/or poor tubes as possible culprits.

It sounds like I just haven't heard a really good tube amp. I also suspected bad tubes in the VTL (bought used) but didn't want to spend the time/money to find out. I have had similar experience with other tube amps though as well so I guess I just gave up. I guess I'll have to give it another shot and look for a CJ or BAT here on A-gon. Thanks again for the friendly advice. I'll have to do some research to learn a little about tubes and the characteristic sound of each!

Some things to think about:
1. Your Plinius is a good amp - you might want to consider putting a tube pe amp in front of it. Both BAT or Blue Circle (BC3) would be good choices.
2. I am not familiar with your CD player, but it is also a likely suspect. After all, is it the most direct link to the source of the music. You might want to consider upgrading it or experimenting with an outboard DAC.
3. You did not mention your power cords, speaker cable, or interconnects. If you are using inexpensive models of these it might be time to consider putting some cash into this part of your system. Experimentation with cords and cabling can yield remarkable results.

Don't be too quick to blame your Plinius, it is a worthy piece of equipment, and may just need to be to be a bit "better fed".