Vermes
Advanced Member level 4
Assumption of the design:
- dimensions: 30x28x9cm
- cheap construcion
- using components which can be found in any lab (3 transformers, power amplifier boards on TDA2052)
The quality of sound was not so important, because of the conditions described above, although TDA2052 as power amplifier is quite sufficient, the same with correction board TDA1074 and idea of input selector board with sockets. TDA1028 and 1039 are perfect for that.
Pictures of construction of the PCB with inputs and selector:
Output sockets (for speakers) with „slowing” system:
Stabilized power supply +21V and symmetrical power supply 2x15V.
System of filters separating stereo signal to L and R (from 100Hz up) and sum of the channels („B”) with a limit above that frequency.
Headphones amplifier:
PCB with input switch provides voltage control for selectors on 1028 and 1029.
Pictures:
Faceplate and rear required mounting brackets (Al 10x10x2mm). They were riveted with aluminum rivets with conical heads, and then over treated with polyester putty. Thus there is no trace of application of paint. The same with bars of M3 screws, brackets for attaching the headphones socket, I and O slots in the front and a switch. Screws were recessed into the panel, tighten with a nut, and then (before being painted with a roller using alkyd black paint) – they were over treated and sanded.
Link to original thread - Coś z niczego, albo 2+1 w warsztacie (coś dla "wzrokowców")