Preamp upgrade

What improvements and sound characteristics are you looking for?

As you own a Bluesound Node, I would recommend getting a better DAC.
I put an Ayre Codex with my Node and the sound quality was greatly enhanced. Add an AQ Thunder power cord to the Codex, and you will hear further refinement.
-Just reporting my experience...
Bob

Hi fellow Tucsonian. The A21 is a very good amp and you should match it with a very good pre-amp. Lots of choices, maybe a QuickSilver?. 

Maybe simply try the P6? ARC tube pre’s go well with the A21...

If you are only streaming ,no turntable, then forgo a preamp and add a DAC to you Node and go direct from DAC to amp. RME ADI 2fs is a great DAC with preamp out and I don’t think adding any preamp in the $1500 to $2,000 range is going to touch it. For $1,500 you can get the RME with a Teddy Pardo power supply and have a great front end. Get a better power cord on your Node, and go balance out from the RME to your A21.

 I’ve listened to your P5 only at local dealership so can’t critique it too hard but it bet pulling it out and getting a DAC with preamp out will be a huge improvement. I have a BS Vault 2 and know firsthand the DAC in the BS players aren’t that great but ok. I have been running direct without my ModWright LS 36.5 in the chain and I’m not sure playing digital sources I’ll throw it back in until I want to play some vinyl so I’ll keep it as it’s still a great preamp. I think you’re spending the money in the wrong place regardless if you want a preamp until you get a better DAC as you are probably going to hear more  with a better preamp that the Node on its own is average sounding and not all that great. The BS players are pretty good at streaming but adding a DAC is a must. There’s other DACs out there with preamp out, but definitely read up on the current RME fs version.

deHavilland gear is renowned. Lots of choices for nice, well made, tube preamps (Quicksilver, Erhard, Rogue, Black Ice, more) and then a good R2R Dac in combination (Denafrips, MHDT, more). I think $2k could just about do both, maybe up to $2500.

Mmm. Maybe I can help. I have an ARC tube hybrid preAmp. Not for sale but can allow you to listen with. I live in Tucson on the Eastside and just started to get back into this stuff.

Oh and I just found this place 
https://www.erhard-audio.com

they are local!