# US 8,542,848 B1 · Musical instrument preamplifier

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,542,848 B1
- Document ID: US8542848B1
- Status: Granted
- Kind: B1
- Application number: 12/189,190
- Filed: 2008-08-10
- Granted: 2013-09-24
- Earliest claimed: 2007-08-13
- Applicants: Thomas Joseph Krutsick
- Inventors: Thomas Joseph Krutsick
- Web page: https://patentgrep.com/patent/US8542848B1

## CPC

- G10H 3/187: {for distorting the signal, e.g. to simulate tube amplifiers (changing the tone color by non-linear elements G10H1/16)}
- G10H: ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE

## Abstract

The present invention provides embodiments of a musical instrument preamplifier. It is especially suited to acoustic and electric guitars and basses. All components, including the power source, are contained within or on the body of the instrument. The preamplifier dubbed BPTD (for Battery Powered Tube Driver) contains a vacuum tube input stage and may utilize a second stage consisting of either a vacuum tube or semiconductor device, such as a JFET. Circuitry is included to bias the cathode heater and the preamplifier circuit with no dangerous high voltages present. The tube may be mounted on the instrument body to provide for a pleasing display.

## Claims

### Claim 1

A musical instrument preamplifier, comprising:
a. at least one vacuum tube having at least one grid, one plate, one cathode, and a means for heating said cathode;
b. circuit components for biasing said vacuum tube as an amplification device;
c. circuit components for coupling said vacuum tube to the musical instrument's sensor or pick-up;
d. circuit components for DC blocking/AC coupling to produce an output signal;
e. a simple power source to bias the preamplifier circuit;
f. and utilizing a voltage divider to bias the cathode heater;
g. whereby said components are contained within or attached to the body of the musical instrument.