I'm considering replacing my passive preamp with a tubes. Is it worth it?

Some thoughts....

There is a big controversy between passive vs active preamp. My thoughts are based on what kind of source you have. If you have a DAC with a nice tube or Class-A output stage, it could be that a passive preamp may be your best choice. It really depends on how the DAC I/V and audio stage translates those DAC pulses into waveforms.

Since you have a Bluesound as your DAC (or iPhone), putting in an active preamp can really help translate more body and mid-bass/bass frequencies. In a sense, it can give the waveforms a lot more muscle.

Unless you’re actually looking for more of the colored tubey/bloomey sound, I would look more towards the stronger/clearer sounding tube preamps. Or look at a nice solid-state Class A preamp. I cannot advise on tube preamps (not my area of expertise), but some solid state amps include the Krell KAV-280p (can be found close to $1k sometimes). The Krell KAV-280p is the oldest Krell I would recommend, but it’s excellent.

There’s a PS Audio PCA-2 up for sale on audiogon. It looks nice with a hefty power supply.

My experience with Bryston preamps (BP-20, SP2) is that they are very clean/clear with lots of attack, but no decay. If you’re looking to get a lot of midrange or mid-bass body, Bryston is somewhat weak in this area (in my opinion).  It’s just not as strong as the Krell is.

It could be challenging to find a good Class A preamp around $1k, but you can do it if you look.

Class A preamp

George,

Are you absolutely sure about that?  If you're talking about tube preamp, I could probably see that as being true because of the nature of how tubes work.  However, solid-state preamps do not necessarily have to be biased into Class A mode.  It's a specific circuit design that does this.  This is true for both monolithic op amps and fully discrete analog circuits.  I have found that if the manufacturer has not specifically stated that their device is Class A, I will assume it's Class AB.