Magnepan 1.7s in a 10x13' dedicated room?

I agree with Zd542. WIth your listening tastes and the room size, *plus* the way Maggies like tubes (assuming your amp has 4-ohm taps), your 35 wpc should be OK.

Consider: the Maggies are rated at 86 dB at 1 meter distance with 1 watt input. That's for a single speaker in an anechoic chamber. When you add the second speaker, it brings it up to 89 dB. When you add the reflections of the room (esp. a smaller one), you add at least 3 more dB. You should be getting close to 90 dB at 1w input at your listening position, especially since you get less volume dropoff from a line source (e.g., Maggies) than a point source (most dynamic speakers).

From there, you double the power required to raise loudness in increments of 3dB. By the time your 35 wpc amp is maxing out, it should be making around 115 dB at your listening spot, which is LOUD.

Rodman9999, what's your point?

I posted "From there, you double the power required to raise loudness in increments of 3dB."

I was adhering to the "double the power for a 3dB increment" principle all along. Start with factory spec 86dB at 1W input in an anechoic room; factor in a second speaker (+3dB=89 dB at 1 wattt) and room gain (another 3-6 dB) and you could get 95dB at 1 watt input per speaker as the stereo in-room starting point. From there, 1x2x2x2x2x2=32 watts as the result of five doublings, making for a 5x3=15dB increase. So in a small room you can hit 105 (my intended figure) to 110 dB (depending on room gain) with around 35 watts x 2, making 70 watts.

06-22-15: Rodman99999You still are trying to figure your power
requirements on a linear scale.

No I'm not, and the 10dB scale and the 3dB scale are not in conflict. It's not
an either/or situation. There are two common ways of looking at amp
power output vs. perceived loudness, and BOTH are logarithmic.

One scale looks at 3dB increases in SPL vs. doubling amp output. That's the
scale I'm using:

1w to produce 95dB
2w to produce 98dB
4w to produce 101dB
8w to produce 104 dB
16w to produce 107dB
32w to produce 110 dB

A doubling of power for a small linear increase IS a logarithmic relationship.

The other scale looks at 10dB increase in SPL (subjective perceived doubling
of loudness) requiring a tenfold output in amplifier power.

In that case, you'd have:
1w to produce 95dB
10w to produce 105dB
100w to produce 115dB.

Galen Carol starts with the 3dB/double the power scale and shifts after two
increments to the 10dB/10x the power ratio, but they're still both
expressions of the same logarithmic relationship between SPLs and the
power required to increase them.

By the 3dB/double the power scale, you need an eightfold increase of power
to see a 9dB increase in SPL. That's not all that different from a tenfold
increase of power to see a 10dB increase.

I'm only claiming a 15dB increase in SPL for a 32-fold increase in power
output. Search the web anywhere; in just about any discussion of amp output vs. speaker output in dB you'll see both relationships given time
after time: double the power for every additional 3dB, or ten times the power
for 10dB additional loudness.