Emission Labs 45 (Pair)
Sound Character of the EML 45
We are often asked to describe the sound of our 45 tubes. If you are looking for real triode sound, the 45 tube is very interesting. It is important that tubes and speakers fit together well. So low power tubes sound best at high efficiency speakers, and vice versa. Best sound of the 45 is developed at the very sweet first Watt. The 45 will reward you with best sound when you are using high efficiency speaker systems, starting at 96..99dB. At the same time, here comes a drawback for the amplifier and the tubes as well. Such speaker systems of 100dB and above will make smallest imperfections audible, and the amplifier must produce as little hum and noise as can be. This is difficult. When you are thinking of 108db horn systems this stresses the design limits of tubes and amplifiers a lot. A quick way to test the noise level of your amplifier-tube combination is, to measure the AC signal out of the amplifier with the inputs muted, but the speaker connected. Anything below 3 millivolt at 8 Ohms is a good achievement, and such an amplifier below 1 millivolt can be called a fine piece of work. If an amplifier will produce low hum with many different tubes, this is definitely a better design, than such an amplifier that is critical on the tubes. Of course, here the tubes play a major role too. At EML we have greatly reduced hum and distortion of all tubes, by a new filament construction. This was done by a real, physical filament center tap, that is positioned outside of the Anodes, but inside the glass bulb. The result was, we reduced the hum level of the EML45 even below that of many good NOS tubes.
Read More Here: http://www.emissionlabs.com/datasheets/EML45.htm