USA Invention Patents: US 10,755,885 B2
USA design patents: US D893,460 S
Vacuum tube audio amplifiers can give very good and pleasant sounds. However, as these amplifiers are generally expensive, bulky and tend to have heat dissipation problems, they are typically designed as high-end products that are still impossible to become common household products. Compared with integrated circuit (digital) audio amplifiers, which are now more popular, vacuum tube audio amplifiers tend to consume larger space with fragile tubes; moreover, when operating, they generate intense heat while the high current is flowing through the filaments within the vacuum tubes. Thus, most of the vacuum tube audio amplifiers are designed to have top-mounted (mostly in high-end type products) or internally mounted vacuum tubes.
The traditional built-in vacuum tube speaker device uses a wooden shell, which is designed to enclose a prior art vacuum tube amplifier and probably a speaker in the device. The housing can protect vacuum tubes from colliding with one another and prevent the user from being scalded by the vacuum tubes when they are operating and generating intense heat. However, the housing makes it difficult for the vacuum tube amplifier to dissipate heat. As a result, the main drawback with the design of an audio device with internally mounted vacuum tubes is its heat dissipation problems; poor heat dissipation will shorten the lifespan of vacuum tubes. In addition, this prior art vacuum tube amplifier includes a metal grounding plate at the bottom part, arranged close to the circuit of the amplifier to reduce the noise generated from the circuit when operating. However, such arrangement causes the prior art vacuum tube amplifier to consume a lot of space and become very bulky. If testing operations need to be carried out, the vacuum tube amplifier with the above design will have to wait until it is assembled with the housing of the speaker device. The testing operations for the whole audio system cannot be performed until the vacuum tube amplifier and the housing are assembled together. The bulky device is thus disadvantageous for establishing an automation production line that includes a testing procedure.
Another prior art vacuum tube audio amplifier apparatus has top-mounted vacuum tubes, which can be separate from speakers to improve heat dissipation. Protective frames are used to provide simple protection for vacuum tubes. Still, the vacuum tube audio amplifier apparatus includes a metal grounding plate (may be a metal housing) at the bottom part for reducing noise; moreover, the apparatus needs to be connected to an external speaker device and thus the whole audio system will consume even more space. In addition, the vacuum tube audio amplifier apparatus has the vacuum tubes arranged on the top of the device to facilitate heat dissipation and system configurations. However, such design makes it impossible for the devices to be stacked up on one another like integrated circuit (digital) audio amplifiers, thus making them impossible to become common household products. Also, as the circuit board of the amplifier is positioned within the apparatus housing while the vacuum tubes are positioned on top of the apparatus housing, testing operations are difficult to be carried out with the non-modular design. Similarly, the testing operations for the whole audio system cannot be performed until the vacuum tube amplifier apparatus is completely assembled, and the bulky device is disadvantageous for establishing an automation production line that includes a testing procedure.
As described above, prior art vacuum tube audio amplifiers have drawbacks associated with space consumption, stacking and heat dissipation, and thus the materials used for them could be restricted (therefore with high costs). In view of the above problems, the present invention provides a device with rear-mounted vacuum tubes, wherein the device can be arranged in a vacuum tube audio amplifier apparatus. The device with rear-mounted vacuum tubes comprises a rear panel, a front panel and a housing. The housing is assembled with the front and rear panels along the horizontal direction. The vacuum tubes are arranged, through an opening of the rear panel, from the inside to the outside of the device, and mounted at the rear of a vacuum tube audio amplifier apparatus; thus, the heat generated by the vacuum tubes can be dissipated to the outside of the device (i.e., into the air). The device with rear-mounted vacuum tubes can be used in a vacuum tube audio amplifier apparatus. The device according to the present invention allows the amplifier apparatuses to be vertically stacked and facilitates mass production of the amplifier apparatuses. In addition, the device with rear-mounted vacuum tubes according to the present invention can achieve the objective of reducing the cost for the machine housing. As the vacuum tubes are located at the rear of the machine, heat dissipation can be improved and the lifespan of vacuum tubes can be prolonged, which, in turn, is favorable for the selection of the machine housing (selection of the materials will not be restricted in order to address the thermal endurance problem). Heat resistance is no longer a problem, and virtually all housing materials can be used, such as PVC veneers or plastic housings which are of lower cost.
In addition, the device with rear-mounted vacuum tubes according to the present invention can reduce the residual noise related to power supply and grounding, thereby eliminating the humming sound effectively; moreover, a metal grounding plate at the bottom part is not needed. Please also refer to U.S.A. Patented No. 10,135,402 B1 for relevant techniques; said application discloses that reducing the size of a vacuum tube amplifier apparatus can avoid leakage currents.
To address the problems described above, the present invention provides a device with a rear-mounted vacuum tube, the device comprising at least one protective cover, a rear panel and at least one PCB, wherein: the at least one protective cover comprises a plurality of heat dissipation holes, a containing space and an opening edge; the rear panel comprises at least one rear panel opening, the opening edge being joined to the rear panel opening; and the at least one PCB is electrically connected to at least one vacuum tube. Moreover, the PCB is mounted to the rear panel opening, so that the vacuum tube is arranged within the containing space of the protective cover.