| US6792120B1 | 2004-09-14 | |||
| US20040240147A1 | 2004-12-02 | |||
| US5012199A | 1991-04-30 | |||
| US4701957A | 1987-10-20 |
CLAIMS
What Is claimed Is:
This Is a very unique device In that St rlchens the tone of the electric bass guitar, especially In the lower octave and a half on the Instrument It Is also very effective for creating a richer tone for other bass register musical instruments. The use of a combination of paper In oil condensers, as described above, with a modern, mass produced thin film one Is particularly unique.
With Sl in the overdrive position the tone of an electric bass guitar can become much less distorted at louder volumes.
I claim:
±. An electronic bass register musical Instrument tube preamplifier. An in line signal preamptification device with a 1/4" input connection and a 1/4" output connection, one volume control, and one tube overdrive switch.
2. An electronic bass register musical Instrument tube preamplifier, as claimed on claim 1, and further Including the use of paper in oil signal capacitors in combination with a modern thin film "orange drop" style capacitor In a 12AX7 preamplifier circuit, as described herein, which richens the tone of bass register musical Instrument electronic signals.
3. An electronic bass register musical Instrument tube preamplifier, as claimed In claim 1, and further including the use of a tube overdrive switch, which drives the plates at either 40vdc or 48vdc, to further reduce distortion and richen tone.
4. An electronic bass register musical instrument tube preamplifier, as claimed in claim JL, and further including a source of DC voltage for driving the plates of a 12AX7 tube. (153vdc typically)
5. An electronic bass register musical Instrument tube preamplifier, as claimed in claim I 1 and further including a source of DC voltage for driving the heater In 1/2 of a 12AX7 tube. (6.3vdc or 12.6vdc)
6. An electronic bass register musical instrument tube preamplifier, as claimed in claim 1, and further Including a grounded metal box containing the components contained In the schematic diagram herein to eliminate RFI. |
ELECTRONIC BASS REGISTER MUSICAL INSTRUMENT TUBE PREAMPLIFIER DESCRIPTION
The Electronic Bass Instrument Preamplifier (hereinafter referred to as EBIP) Is an audio preamplifier section for electric bass guitar and other amplified bass register musical Instruments. The basis for the EBIP invention is not in the circuit schematic that It uses, but in Its use of paper in oil capacitors and In the use of these capacitors combined with a modern thin film capacitor in the circuit It uses one half of a 12AX7 tube, and there is a switch which allows the tube to be overdriven for a more enhanced effect. The input socket must be isolated from the ground for RFI (radio frequency interference) reasons.
Paper In oil capacitors have not been manufactured for use by the general public since the 1950's, but today there has been a resurgence of their use in high end audio equipment. In the following schematic Cl is a Mylar paper in oil capacitor. C2-C3 consists of two λ7uf copper foil paper in oil capacitors in series. C4 is a modern "orange drop" capacitor, and CS is a ceramic disc capacitor. All resistors are of the 1/2 watt value. The B+ voltage of 153vdc is only a typical voltage, and other voltages would work equally as well with some adjustments to the values of Rl, R2, and R4. A grounded metal box contains the electronic components of the EBIP.
The circuit contains one volume control In its last stage, and the EBIP Is designed to be placed in the signal circuit between the instrument and the amplifier.
The heater for the tube needs 6.3vdc or 12.6vdc. The heater circuit Is not shown in the schematic, but is incorporated herein as Is typical In such tube circuits.
The present invention has been described according to a preferred embodiment thereof. It Is understood that modifications can be applied to the form, disposition, and values thereof without exceeding the scope of the present invention.
BACKGROUND OF THE INVENTION
In or around 1960 a change in the tone of audio amplifiers was apparent The first transistor radios were being mass produced during this period, and a new process for manufacturing signal capacitors was developed and used. The new capacitors were smaller and easier to mass produce.
Most musical Instrument amplifiers were still tube amplifiers at this time, but they began to use the modern signal capacitors. This did not affect the tone of musical instruments in the treble register as much as it did musical Instruments In the bass register (eg. Tone controls on bass guitars no longer changed the tone very
noticeably, compared to what they would do when playing through an amplifier made before the advent of the new process signal capacitors.
In the late 1960's through the 1980's most musical instrument amplifiers began to be produced as solid state amplifiers. These amplifiers were not an Improvement In tone, but an Improvement in manufacturing process. By the 1980's certain amplifier and effects manufacturers began to introduce 12AX7 tube preamplifier circuits that were fairly effective in making the tone of treble register instruments richer and less distorted. Bass register instruments were not affected to the same extent, and new ways of playing the electric bass (eg. slap picking, etc.) were developed. Further development of digital effects processors has to some extent improved the tone of bass register instruments, and the preamplifier circuits utilized in Kennedy (US Pat. No. 4672671) and Kennedy et al. (US Pat No. 4644289) which make use of two sides of a 12AX7 tube, creates a richer and less distorted tone, much In the same way as the EBIP Invention.
The present invention has been described according to a preferred embodiment thereof. It is understood that modifications can be applied to the form, disposition, and values thereof without exceeding the scope of the EBIP invention.
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