Vermes
Advanced Member level 4
It is a cheap construction of guitar amplifier similar to small Fender 30W. Housing was made of 15mm thick plywood, but it also can be up to 18mm. 4 pieces 20cm (top and bottom cut to 32cm) were cut, sides cut in order to get the middle of 32cm x 26cm. Length of the sides depends on the thickness of material used. Everything should be glued with adhesive and screwed (8 screws). When dried, cut the corners, because plastic corners are rounded and they would not fit tightly. Then cover the housing with artificial leather with a width of 30cm and a length of 1,35m. The best way is to apply the adhesive on the amplifier and artificial leather and then glue, starting from the middle so the end of gluing will be underneath the amplifier. Protruding sides of the artificial leather should be bent inwards and glued. After that use eight corners and handle.
Front is made of 20mm thick board with dimensions of 22cm x 31,6cm, so it fits. Cut a hole with diameter of 17cm in the middle, and diffuse holes with diameter of 5cm in the bottom sides. Screw the speaker to the inner side and put the screws inside the board. Cover the front with a material using staples inside. Such prepared front should be put inside 1cm deeper than the sides and screw it with three screws and upholstery pads (a pad on each side and bottom).
Use of broadband speaker with hard suspension is recommend. Transformer TS40/041 is better than toroid, because it is cheaper and 2x15V (it can be another one, but remember that the power should be not less than 30W). 8A flat graetz and two electrolytes 4700uF 25V are also needed for the power supply. Minimum 3m cable should have 3 wires, so you can easily reset. Zero should be screwed to chassis, what will completely clean any hum. A piece of aluminum sheet (with dimensions of 31,5cm x 31,5cm and 1-1,5mm thick) can be used to create the chassis. Just bend it into U shape with one side longer. Front of the chassis is 4cm, 1cm from the bottom should be bent inwards to gain rigidity and finish, the depth is 15cm. Bend the rest into U shape and then screw the power amplifier together with the power transistor.
In the original amplifier, there was a terminal on a small chip screwed to the plate and it was only 12,5W sinus, but it played well, because of the good quality speaker used. You can use J35 kit or a terminal from old Radmor, or any other.
Back of the amplifier is made of 2cm thick board. It should be covered with the artificial leather and sides bent to the inside. It is good to cut it 2mm less from each side so the artificial leather can fit. Screw the back with screws on pads, two on each side.
Preamplifier is a very improtant part of the amplifier, because it provides all the characteristics and sound. The preamplifier schematic, front panel and other useful information can be found at the original thread.
Link to original thread (useful attachment) – Piec Gitarowy dla Każdego !
Front is made of 20mm thick board with dimensions of 22cm x 31,6cm, so it fits. Cut a hole with diameter of 17cm in the middle, and diffuse holes with diameter of 5cm in the bottom sides. Screw the speaker to the inner side and put the screws inside the board. Cover the front with a material using staples inside. Such prepared front should be put inside 1cm deeper than the sides and screw it with three screws and upholstery pads (a pad on each side and bottom).
Use of broadband speaker with hard suspension is recommend. Transformer TS40/041 is better than toroid, because it is cheaper and 2x15V (it can be another one, but remember that the power should be not less than 30W). 8A flat graetz and two electrolytes 4700uF 25V are also needed for the power supply. Minimum 3m cable should have 3 wires, so you can easily reset. Zero should be screwed to chassis, what will completely clean any hum. A piece of aluminum sheet (with dimensions of 31,5cm x 31,5cm and 1-1,5mm thick) can be used to create the chassis. Just bend it into U shape with one side longer. Front of the chassis is 4cm, 1cm from the bottom should be bent inwards to gain rigidity and finish, the depth is 15cm. Bend the rest into U shape and then screw the power amplifier together with the power transistor.
In the original amplifier, there was a terminal on a small chip screwed to the plate and it was only 12,5W sinus, but it played well, because of the good quality speaker used. You can use J35 kit or a terminal from old Radmor, or any other.
Back of the amplifier is made of 2cm thick board. It should be covered with the artificial leather and sides bent to the inside. It is good to cut it 2mm less from each side so the artificial leather can fit. Screw the back with screws on pads, two on each side.
Preamplifier is a very improtant part of the amplifier, because it provides all the characteristics and sound. The preamplifier schematic, front panel and other useful information can be found at the original thread.
Link to original thread (useful attachment) – Piec Gitarowy dla Każdego !
