Novel Preamplifier Circuit Configuration

An audio preamplifier for processing an audio input signal comprising:

• a first triode in a common cathode configuration configured to perform a first gain function accentuating one of low frequencies and mid-range frequencies in response to user input;
• a first biasing circuit coupled to the first triode configured to emphasize low frequencies and a second biasing circuit coupled to the first triode configured to emphasize mid-range frequencies;
• at least one second triode in a common cathode configuration configured to perform at least one second gain function accentuating one of low frequencies and mid-range frequencies in response to user input;
• at least one second biasing and coupling circuit coupled to the at least one second triode configured to emphasize low frequencies and at least one second biasing circuit coupled to the at least one second triode configured to emphasize mid-range frequencies;
• and
• a third triode coupled to the at least one second biasing circuits configured to perform a tone stack function in response to user input.

An audio preamplifier for processing an audio input signal comprising:

• a first stage including a first triode in a common cathode configuration configured to perform a first gain function favoring one of low frequencies and mid-range frequencies in response to user input;
• a first biasing circuit coupled to the first triode configured to emphasize low frequencies and a second biasing circuit coupled to the first triode configured to emphasize mid-range frequencies;
• a second stage including a second triode in a common cathode configuration configured to perform a second gain function favoring one of low frequencies and mid-range frequencies in response to user input;
• and
• a second biasing circuit coupled to the second triode configured to emphasize low frequencies and a second biasing circuit coupled to the second triode configured to emphasize mid-range frequencies.