I am not familar with your amp, but I know of a few members here that use those speakers, but don't vistit the forums ever. So tell me the wattage and I'll ask them what they think.
Not sure but I think your speaker has a sensitivity of 88db (1 watt at 1 metre). Is your model number the SP2/3? 88db is not good for a 2A3. Generally you will not get good performance with that rating. Folks differ with what they want but I would want high 90s at least. It doesn't make much diff what the wattage rating. I believe it is 100. If 100 was the sensitivity rating you would be all set.
I do not think you will be happy with the combination if my numbers are correct.
I have the Spendors (think they are great). I have not tried with 2A3, but have used 300B SE. It was sufficient about 95% of the time in my medium sized room, backing off the gain and listening a little quieter than I would have liked (I listen normally at moderate levels) made the amp usable with the rest. You are talking about 3 watts to the 300B's 10 watts, so my suspicion is that you are probably right on the cusp. This is a situation where I would try and borrow the amp you are considering or a similar amp to find out for yourself if you can live with it. Since SE amps are such a specialized item, I would try to find a dealer who would let you borrow one for a few days (give your dealer a break, he needs his "demo", offer to borrow it on Sat at closing time and return Monday and take GOOD CARE of it!). The other alternative; I believe Wright Sound (who makes some highly regarded amps) offers a trial period and makes a 2A3 amp, check his website for details (I have no connection to them...).
3ox: I was not knocking the speakers. I am sure they are great sounding when paired with suitable amp. 3ox is right make sure you listen in your room before you buy. I do not think that you are going to find yourself on the "cusp" however. Listen to 2A3s with effecient speakers and then your Spendors. Most modern speakers were not designed for use with 2A3s. A lot of this depends on your ears which will change overtime. I would be surprised if you would be happy with the Spendors for long. Frankly, I think 300bs pushing them would be on the cusp. Again, only my ears.
Didn't think you were knocking the Spendors, Clueless. And a 2A3 would not be MY first choice generally for an amp for the Spendors. But that's what Wda specifically asked about. The numbers say 88db/eff. plus 3db (pair of speakers) minus a little (you will be listening further than 1 meter away!) meaning a 3 watt amp will play about 90db peaks which to me is reasonably loud, but you can certainly run out of steam sometimes. I use, among others, a Leak Stereo 20 (P-P 6BQ5's, about 15 watts or so) and don't run into trouble. The Spendors fortunately have a fairly benign impedance curve (mostly over 8 ohms) so they do lend themselves to tubes. 300B's at 10 watts will do about 95db or so which is a little more like it. But your mileage may vary! Kevin
It will give you a taste of what the 2a3 will do, but in the long run you'll be looking for either a different amp or speaker. I'm currently running a 2a3 with an 89dbw meadowlark and it's close at low volume, but not advisable. Given your room size and musical tastes, either start thinking about new speakers, or look for more power in a 300b.