[slefley]

I have 1978 version LS3/5A, 15 ohm speakers currently working great with mono ACA amps.  I listen near field at around 85 db max. Has anyone tried a setup like this with a 300B amp?

[galyons]

No personal first hand experience. The published sensitivity is 82.5dB 1w/1m at 15 ohms. Most 300B set amps will provide 6-10 amps into 8 ohms.   Does the amp have a 16 0hm output tap? That would maximize the available power.  If not, 8 ohm taps would suffice.   So the amp should drive the speakers for near field listening.

Cheers,'
Geary

[NickMimi]

Yes, i have played my Falcon 15 Ωhm LS3/5A’s using a low power 300B in a small room, near-field. Usually under 70db, very relaxed setting. I have absolutely enjoyed the experience.

[JLM]

Had a 7 wpc solid state amp serving 90 dB/w/m, 30-20,000 Hz, 8 ohm loudspeaker that did remarkably well.  But bumping up to 40 wpc turned the loudspeakers from polite gentlemen wearing sport coats into NFL linebackers in tuxes (much more resolution, improved grip on the drivers, greater dynamics).

[mick wolfe]

I have 1978 version LS3/5A, 15 ohm speakers currently working great with mono ACA amps.  I listen near field at around 85 db max. Has anyone tried a setup like this with a 300B amp?

If those ACA mono's are 8 watts per channel and they're currently working for you, a 300B amp will be more than fine. In fact, it think it will play even louder with greater sense of ease. Just my experience in regard to solid vs. tubes given equal power ratings.

[mick wolfe]

Make that "solid state" vs. tubes. It appears I haven't had enough coffee yet.