The need for a homemade amplifier regularly arises among guitarists. A concert set is usually located in a rehearsal room. It weighs a lot, it is inconvenient to carry it with you every time, so there is a desire to collect something for home rehearsals. However, such an amplifier can also be used at concerts. Its output power reaches 3.5-4 W with a fairly high sound quality.
It is necessary
- - power supply from an old tube receiver or radio;
- - radio tube and socket to it;
- - variable resistance 220 kOhm;
- - input socket;
- - assembly wire;
- - a piece of plywood 3-5 mm thick;
- - fine brass mesh or radio fabric;
- - output transformer from a tube receiver or TV set;
- - case cover from an old CD or DVD drive;
- - electric drill;
- - jigsaw;
- - soldering iron, rosin, tin.
Instructions
Step 1
In the case cover, mark and drill holes for the socket and for fastening the TVZ transformer or the like. Fit the parts to the chassis cover. In its side wall, mount the socket of the input connector, a variable resistor, which is the amplifier's volume control. If the power supply does not have a switch, install it in the side wall as well. Try to keep all of the items mentioned on the same side of the chassis. If the parts you have have fasteners, make the necessary holes for them.
Step 2
Mount the radio components on the chassis according to the attached diagram. Do not insert the lamp yet. Keep in mind that the high impedance winding of the output transformer is included in the anode circuit of the lamp
Step 3
Attach the speakers to a separate wood or plywood panel by cutting holes for them. It can be 2 speakers of 1.5 W each from a TV or radio. Maybe 1 speaker 3-4 W from a tube radio. Speakers can be of different shapes. You only need to provide a total power of at least 3 W and a total resistance when connected in parallel with 3-8 Ohms
Step 4
Protect the speakers with fine brass mesh or radio cloth if desired. If you are using two speakers connected in parallel, they need to be phased. Choose such an inclusion in which the diffusers will be pulled in or pushed out at the same time if a low voltage constant current is applied to their circuit (for example, from a battery)
Step 5
Connect the power supply, amplifier and speakers so as to apply an alternating voltage of 6, 3V to the filament. Connect a constant anode voltage of 210-300 V, and connect the negative to the chassis body. Connect to the output (low impedance) winding of the speaker output transformer. Insert the lamp into the panel. Plug in the amplifier. If it is assembled correctly, then after two to three minutes of warming up, it will be ready for use. If at the same time a loud humming sound is heard from the speakers, then you need to swap the wires connecting them to the output transformer.
Step 6
Use a guitar cable to connect the amp to your electric guitar. Adjust the volume control of the amplifier to achieve the greatest sound intensity.. When the guitar control should be set to the maximum volume position. This amplifier usually does not require additional adjustments and settings.
Step 7
Make a case out of plywood. The power supply can be positioned at the bottom and the amplifier chassis can be positioned above it. Other layout options are also possible. If you wish, you can decorate the case with leatherette, mount carrying handles on it, etc.
