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I like the look of the Raphaelite kit (the right hand picture) by the way. To put the price into perspective this link is to another kit that is twice the price (but very nice by the look of it)
http://www2.big.or.jp/~sunaudio/index_e.html
I decided not to go the kit route because I like learning all the engineering stuff that's required to design and build my own. This takes more time and effort and if I include the tools and things along with my time - a kit would be the more economical choice. If you just want a good amp to build there's much to recommend a kit - the hassle of cutting and drilling the chasis alone is a misery for some folk.
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Lightsabre, though many highly respected peers here have replied, I continue to believe that you need to embrace an understanding of power, watts and dB that so far seems to elude most people, most of the time.
First, power. Watts. P = I E (power roughly equals current I times voltage E)
Second, decibels: dB = 10 log₁₀ ( P₁ / P₂ ) … which is to say ten times the log (base 10) of the RATIO between two power levels. If say, 100 watts versus 1 watt:
10log₁₀ ( 100 ÷ 1 ) =
10log₁₀ (100) =
10 × 2.0 =
20 dB
Therefore, all other things considered, 100 watts would be 20 dB louder than 1 watt.
Third, sound pressure sensitivity: dB/W … you'd think this is decibels per watt, wouldn't you? It is avowedly not. It is the sound-pressure (in acoustic decibels) produced by a speaker measured 1 meter from the front face centered, when driven by 1 watt of incoming power. An 86 dB/W speaker will deliver 86 acoustic decibels of sound pressure (pretty loud, but not painfully so) from that speaker. But 0.1 watts delivers only 10 dB less, or 76 dB. Remember … 10log₁₀ (0.1 ÷ 1) = –10 dB.
By the same token, 30 watts driving the same speaker, all things considered:
dB = 10log₁₀ ( 30 ÷ 1 )
dB = 10 × 1.47
dB = +14.7
So, 86 + 14.7 roughly equals 100 dB of sound pressure. Assuming the speakers are quite linear. Which they might be!
Are you now starting to see why your original question about speaker sensitivity and “apparently” low wattage output of tube amplifiers is a bit misinformed? In short, for rather impressively high quality listening, and not just window rattlingly loud sound, “a few watts” is enough to deliver; its kind of like everything: quality amplification simply doesn't produce the peak or even the average watts of a lower quality solid state amplifier at the same price, but there is in the end only perhaps a 6 dB or so difference in the real amount of "loudness" that it produces.
And for many of us, giving up 6 dB of loudness to get eminently sweet amplification is a tradeoff not just accepted, but embraced. Like the difference between an Hershey's chocolate bar, and a fine stick of triply blended Belgian chocolate. Mmmmmmm… less, is more.
GoatGuy
First, power. Watts. P = I E (power roughly equals current I times voltage E)
Second, decibels: dB = 10 log₁₀ ( P₁ / P₂ ) … which is to say ten times the log (base 10) of the RATIO between two power levels. If say, 100 watts versus 1 watt:
10log₁₀ ( 100 ÷ 1 ) =
10log₁₀ (100) =
10 × 2.0 =
20 dB
Therefore, all other things considered, 100 watts would be 20 dB louder than 1 watt.
Third, sound pressure sensitivity: dB/W … you'd think this is decibels per watt, wouldn't you? It is avowedly not. It is the sound-pressure (in acoustic decibels) produced by a speaker measured 1 meter from the front face centered, when driven by 1 watt of incoming power. An 86 dB/W speaker will deliver 86 acoustic decibels of sound pressure (pretty loud, but not painfully so) from that speaker. But 0.1 watts delivers only 10 dB less, or 76 dB. Remember … 10log₁₀ (0.1 ÷ 1) = –10 dB.
By the same token, 30 watts driving the same speaker, all things considered:
dB = 10log₁₀ ( 30 ÷ 1 )
dB = 10 × 1.47
dB = +14.7
So, 86 + 14.7 roughly equals 100 dB of sound pressure. Assuming the speakers are quite linear. Which they might be!
Are you now starting to see why your original question about speaker sensitivity and “apparently” low wattage output of tube amplifiers is a bit misinformed? In short, for rather impressively high quality listening, and not just window rattlingly loud sound, “a few watts” is enough to deliver; its kind of like everything: quality amplification simply doesn't produce the peak or even the average watts of a lower quality solid state amplifier at the same price, but there is in the end only perhaps a 6 dB or so difference in the real amount of "loudness" that it produces.
And for many of us, giving up 6 dB of loudness to get eminently sweet amplification is a tradeoff not just accepted, but embraced. Like the difference between an Hershey's chocolate bar, and a fine stick of triply blended Belgian chocolate. Mmmmmmm… less, is more.
GoatGuy
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