GB2212331A

GB2212331A - An audio amplifier

Info

Publication number: GB2212331A
Application number: GB8726322A
Authority: GB
Inventors: Farad Azima
Original assignee: Mission International Ltd
Current assignee: Mission International Ltd
Priority date: 1987-11-10
Filing date: 1987-11-10
Publication date: 1989-07-19
Also published as: GB8726322D0

Abstract

An audio amplifier having a chassis 1 on which the amplifier components are mounted, the chassis consisting of a metal casting, preferably die cast aluminum, and being formed integrally with a heat sink 7 to which electronic power output devices can be directly thermally coupled. <IMAGE>

Description

TITLE: AN AUDIO AMPLIFIER The invention relates to amplifiers for high fidelity audio equipment. It is known that electronic apparatus of this nature can produce substantial quantities of heat during use and that this heat must be dissipated to protect the electronic components of the amplifier from failure due to their becoming overheated.

It is known to attach heat sinks to the power output devices of audio amplifiers to dissipate the unwanted heat and it is also known to mount air circulating fans inside the casing of the amplifier for the same purpose.

Some audio amplifiers have large heat sinks which are attached to the amplifier casing so that their heat dissipating fins are visible externally of the amplifier.

The known solutions to the problem of dissipating unwanted heat efficiently are often expensive to produce in production quantities and nevertheless problems with overheating are still common.

It is an object of the invention to mitigate these difficulties.

According to the invention there is provided an audio amplifier having a chassis on which the amplifier components are mounted, the chassis consisting of a metal casting and being formed integrally with a heat sink to which electronic power output devices can be directly thermally coupled.

From another aspect the invention is a chassis for an audio amplifier, the chassis consisting of a metal casting on which the amplifier components can be mounted, the chassis being formed integrally with a heat sink to which electronic power output devices can be directly thermally coupled.

In this way the whole of the chassis is directly thermally coupled to the output devices so as to increase the area available for heat dissipation. In the past even although the output devices, their associated heat sinks and the chassis were united by fastening devices such as bolts or screws, the thermal path was indirect and thus less efficient.

Preferably the chassis is die cast to avoid the need for subsequent machining and preferably the chassis is made from die cast aluminium. The heat sink is preferably finned in conventional fashion to increase its area of heat dissipation, and preferably the arrangement is such that the fins of the heat sink are disposed, at least in part, on an external surface of the chassis. If desired the fins may be arranged so that their extremities are flush, i.e. they do not extend beyond, the general outline of the amplifier casing. For this purpose, the heat sink may be disposed in a recess on one side of the amplifier casing.

Preferably the amplifier casing comprises a die casting which, together with the die cast chassis forms a housing for the electronic components of the amplifier. Preferably the chassis is formed as a tray having an opposite pair of upstanding peripheral walls and advantageously the pair of walls may be connected by a third upstanding peripheral wall at one end of the chassis.

The invention is diagrammatically illustrated, by way of example, in the accompanying drawings in which: Figure 1 is a perspective view of an audio amplifier chassis; Figure 2 is a further perspective view of the chassis of Figure 1, and Figure 3 is an underneath plan view of the chassis of Figures 1 and 2.

In the drawings a chassis 1 for an audio amplifier is die cast in one piece in aluminium in the form of a generally rectangular tray having a base 2 which is surrounded on three sides by upstanding peripheral walls 3, 4 and 5 respectively. The chassis has cast into it lugs (not shown) for receiving circuit boards or other components of the amplifier and an aperture 6 for an electrical power input lead. In addition cooling slots (not shown) may be cast into the base 2 or walls 3, 4 and 5.

Extending into the chassis 1 from one side is a large heat sink 7, the cooling fins 8 of which are disposed so that their extremities are flush with the plane of the side 5 of the chassis. The lower extremities of the fins 8 are arranged to be flush with the underside of the chassis. The heat sink 7 is arranged to present a flat face 9 towards the interior of the chassis and is adapted to receive power output devices which may be clamped or otherwise secured to the heat sink to provide a good thermal connection therebetween.

The chassis 1 forms the basis of the amplifier casing (not shown) which is completed by an upper part which is complementary in shape to the chassis 1 in that it comprises a rectangular section from which depend three peripheral walls which mate with the walls 3, 4 and 5 to form a box-like structure, the open end of which is closed by a front panel (not shown) on which the usual amplifier controls and switches can be mounted.

The chassis of the invention simplifies manufacture of audio amplifiers and provides efficient cooling of the power output devices in a cost effective manner.

Claims

1. An audio amplifier having a chassis on which the amplifier components are mounted, the chassis consisting of a metal casting and being formed integrally with a heat sink to which electronic power output devices can be directly thermally coupled.

2. An audio amplifier according to claim 1, wherein the chassis is die cast.

3. An audio amplifier according to claim 1, wherein the chassis is made from die cast aluminium.

4. An audio amplifier according to any preceding claim, wherein the heat sink is disposed, at least in part, on an external surface of the chassis.

5. An audio amplifier according to claim 4, wherein the heat sink fins are arranged so that their extremities are flush with one side and the bottom of the chassis.

6. An audio amplifier according to claim 5, wherein the heat sink is disposed in a recess on one side of the chassis.

7. An audio amplifier according to any preceding claim, comprising a casing having a die cast top which, together with the die cast chassis forms a box-like enclosure.

8. An audio amplifier according to any preceding claim, wherein the chassis is formed as a tray having an opposite pair of upstanding peripheral walls.

9. An audio amplifier according to claim 8, wherein the pair of walls are connected by a third upstanding peripheral wall at one end of the chassis.

10. An audio amplifier substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

11. An audio amplifier chassis consisting of a metal casting on which the amplifier components can be mounted, the chassis being formed integrally with a heat sink to which electronic power output devices can be directly thermally coupled.

12. An audio amplifier chassis substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.