300B-XLS 'Blade'
Description
- 300B SE, Single Ended Tube Amplifier
- Tubes used : Emission Labs 300B-XLS, 12BH7, 6H30
- Neutral 300B sound with exceptionally fine detail and resolution
- Large size, Single Ended Output Transformer, for transparent sound reproduction and excellent dynamic behavior.
- With very low feedback design for increase damping factor.
- Exactly customizable in 3 stages for 4 ohm to 8 ohm speaker
- Suitable for loudspeaker boxes of 86 db or higher.
- Version: BLADE 1.0 --- 03.05.2019
Are you interested?
About the 300B-XLS tube, used here
This tube behaves like any normal 300B tube, if biased as such. So that is one first application, and many use it like this, for the more dynamic sound. This is due to the slightly heater current, compared to the standard 300B. (Read the Tung-Sol 5751 data sheet for similar explanation for the 5751 tube, compared to 12AX7)
A second application, also used many times, is using the 300B-XLS at higher dissipation. This allows the use of medium efficiency loudspeakers beginning at 86dB, and the sound stays fresh and lively. Unlike standard 300B would not have the dynamic power any more for such speakers. (Standard 300B requires appr 89dB speakers or better). It's a bit personal, how many dB a speaker would need a s a minimum, but why choose the tube such that you have the minimum (?!). Sure is, 300B-XLS can do 3dB more with the right schematic.
About the transformer, used here
Mr. Leven supplies his own transformer, and performance in his documentation refers to this.
Alternatively it is possible to use LL1623-120mA. See also here for dual impedance PCB's