How many watts per channel are enough?

Sufficient, but just barely.
89db for speakers is rather inefficient.
I would say no way.. but if you never ever want to crank it up, you might get by with 34 watts.

To play softly only takes a watt. the trouble is the moment you add in any real bass notes and are slightly louder ...zoom you are using way more watts.
I do not have the link wit this info, but my speakers use about 1 watt up to 20 watts at lower listening levels.. Then a moderate level with bass the wattage jumps to 80watts.. as soon as I crank it up a little the wattage needed is 400 watts..

Same for your 89db efficient speakers.
I think you should look for a more powerful amp.
Or more efficinet speakers.
If you had 92db efficient speakers. you could easily use the amp you want.

To be sure, you'll run out of headroom real quick once you start pushing that
volume knob into loud territory. That's why they make efficient speakers and
powerful amps!

I'm a fan of efficient speakers for sure. Even those *honest* 93dB/Watt speakers
I had were a little on the low side for me. I found the step up to 95dB or 96dB to
be very worthwhile. Unfortunately, the efficiency ratings assigned by
manufacturers seems to be oft abused and "fudged". Speakers should be
measured anechoic, not just on a single frequency that happens to be a
significant peak, and (ideally) not at the expense of decent bass extension. In-
room efficiency ratings are...misleading.

I've seen a posting from a well known system/room optimizer who measured a
set of "famous maker" 97 dB/Watt speakers at 3dB LESS than a 96dB/Watt
speaker from a different manufacturer.

It is hard to tell without having experience with the amps

the reason I say this is because I once had a Stingray amp (rated at 40 watts) and it was quite lively driving my Maggie 1.6 speakers however, Rogue 120M (120 watts) sounded a bit dull and lacking dynamic range. Both had new tubes.

maybe the archives have more info on the ability for each amp to drive a real life load.

fwiw

good luck

Agree with Liz. You've got a nice sized room. I'd be looking for 50 to 75 tube watts at the very minimum. I think a good rule of thumb with amps is to err on the high side. Of course, I'm not talking about 400 wpc mono-blocks. But in your case, I advise erring on the side of more watts.

Btw, I listen to classical music too. Just listened to Beethoven's 9th. Before that, Prokofiev's Symp #1. The drums rolls are really dynamic. I think a 34 wpc amp will run out of runway real fast trying to keep up.

I use the PL 5 with Opera Platea floorstanders (86 db sensitivity) in a 26' x 15' X 9' room. I use either EL 34 or 6CA7 tubes, which give you a few less wpc than if you use KT88s. I listen to CDs almost exclusively. The front end is a Musical Fidelity CD PRE 24 cd/ preamp.

It comes down to four items to consider:

1. how loud you play your stereo
2. what types of music you listen to
3. how noisy is the street you live on
4. do you live in a private house or an apartment house

I live in NYC (Queens) in an apartment house on a major road which connects to the LIE and supports a major bus route and a fire house.

With all that said, the PL5 will play plenty loud if you listen at low to moderate levels. If you like your music loud, you are probably looking at a solid state amp or a more expensive (and powerful) tube amp.

Rich