Sub driver class A
• active lowpass subfilter
• balanced mono output
• decoupled channel summation
• zero stereo impairment
• Filter Class A with JFet cascade
• separate signal (0) and shield mass (S)
• Level and frequency via switches
• zero potentiometer, hum, noise
• sub driver: 100 x 58 mm, high 12 mm
• sub driver 58,-
• sub driver - supply: 100 x 100 mm, high 40mm
• sub driver - supply class A 98,-
• sub driver - supply - trafo: 100 x 175mm, high 40mm
• sub driver - supply class A - trafo 138,-
The sub driver generates the analog deep bass signal for the subsequent amplification from the stereo input.
Correction and pre-filtering are done without gimmicks.
The limit frequency, which is designed for a reasonable range, and the level for adaptation to the satellites are set.
We do not use inequalities, scattering or inhibiting layers of coal from Pots.
Two phase-shifted signals are available at the output.
An existing stereo amplifier can be used symmetrically - each stereo channel receives one signal, the speaker is then connected to both "plus poles" L + R.
Prerequisite: The stereo power amplifier has no capacitors in the signal at the output.
Any mono amplifiers are operated at one of the two outputs if they do not have a balanced XLR input.
The experimental setup shows the sub driver in a balanced arrangement with two SAC amplifiers.
Since the transformer for the output stages (not in the picture) also supplies a reduced auxiliary voltage, the sub driver with Class A power supply was chosen here but without its own transformer.
The class A voltages are looped to the side in the sub driver in order to be able to connect further pre-stage components.
SAC amplifiers for the drive of the satellites remove low-frequency loads by changing only one capacitor without additional active crossover.