Difference in 300b and 845?

More oomph (technical term) for one thing. I've had 845 SET monoblocks in my system for 8 years and when I hear a 300B amp here, it lacks the authority to move me. Which of course depends to a large extent on the speakers' sensitivity, and maybe yours, like mine, need the extra power that 845s provide.

Also, 845s seem to have a different quality of sound, hard for me to describe, than 300Bs. Certainly each has its adherents, and you might well end up liking your 300Bs better.

Finally, it's a question of WHICH 845s. The various 845 tubes in current production do sound different, and unfortunately I've found that the Shuguang Pavanes -- which cost twice as much as the more common 845A and 845B versions -- float my boat. I don't even want to hear the NOS stuff.

The sound of an 845 must invariably reflect its higher wattage "dissipation". They also seem to have an overall richer tone. I suppose upon reflection, this may be the result of mid bass and bass emphasis. I am quite fond of this rich tone, but I am not sure if it is a "coloration" or not.

For both tubes, the circuit and the execution quality of same in the amp are highly influential. Both are triodes commonly used in single-ended amplifier topology. While it's possible to get a 300B amp with disciplined bass, and it's possible to get an 845 amp with very high resolution and classic SET midrange, *generally* what you're missing by not having an 845 based amp relative to 300B, is superior drive, dynamics and broadly usable deep bass and slam. The 845 tube usually outputs 3X the power of a single 300B in SET use, and sounds like more. But particularly, bass quality is, all other things being equal, more natural, more defined, more impactful and more dynamic with the 845 than the 300B.

With equally good components and design, 300B amps generally reveal finer detail, having higher resolving traits than an 845 counterpart amp. But an 845 SET amp has plenty of midrange single-ended and triode magic, with generally more linear bass. What you're missing most in 300B that 845 delivers is compelling drive.

Phil

Phil, thanks for the info, So I have a Viva 300p and Zu Presence speakers

I have plenty of volume but my woofers never move

Does that mean the speakers are not functioning at a optimal level?

Do your woofers move on your Presence?

thanks again,Scott