1. Don’t rush to sell your old speakers
You feel that your tube box head is getting weaker and weaker. It sounds more tired than Hanazawa. Is there anything wrong with it? Feel that the details are under-represented, the high frequencies are blurred or the low frequencies are loose? If this is a guitar, you might change the strings, or check the neck, or readjust it according to professional standards. However, when it comes to the speaker, you may simply put it on the second-hand equipment sales area of Guitar China and sell it and post some money to buy a new one, right?
In fact, you can still implement many measures to make your old speakers rejuvenate, such as regular power checks (pay attention to the lethal high-voltage current inside!), simple welding, internal cleaning and even replacement as mentioned in the second point. Electron tube. Of course, we recommend that you seek professional maintenance personnel to check the speakers for you.
2. The tube is not broken, it may just be tired
The timbre symptoms mentioned in one point are largely due to your tube being too "worked" unless you (or your technician) can clearly point out that something is wrong. If not, you probably need a new set of tubes, especially if the tubes have not been replaced for a long time. How often you change it depends on the duration of the speaker and your usual intensity of use. The replacement of the rear pole tube is generally more frequent than that of the front stage, and the bias voltage (rebias) needs to be readjusted after installation. You can check your instruction manual (if you have one).
3. The capacitor of the filter also needs to be replaced regularly
Although those huge "electrolytic capacitors" seem to be securely soldered there, it does not mean that they are always as strong as new. If any amplifier has been used for more than 10 years, it is time to replace it with a new capacitor. They may still work properly, but they may also make your low-frequency sound less powerful, or even make the overall sound a lot of color, and it is very likely that they will stop working at any important moment. Generally, larger capacitors need to be paid more attention, and the smaller capacitors at the front stage should not be ignored.
4. Fix your tube socket
Old amp heads, especially those that have undergone many tube changes, will have a little looseness at the junction between the tube socket and the pin. Generally speaking, this is the job of a professional electrical repairer, because there will be high voltages, but it is not difficult to fix the joints tightly, just use the tip of a small screwdriver to carefully break the metal contacts back to the original position. . At the same time, you can also check whether the tube pins and joints are oxidized to form an oxide film. You can apply some cleaning agent to the pins properly, and you can plug and unplug the tube back and forth to make the cleaning agent apply more evenly.
5. Clean the knob
The speakers are worn out, and a common problem is that noise appears when you turn the volume or tone knob. Sometimes turning the knob several times quickly can temporarily make the noise disappear for a while. But this is not a long-term solution. Open the case, spray circuit cleaner into the potentiometer wiring and the gap, and then quickly turn the knob. If it still doesn't work, it's time to change a potentiometer, which can be found in some places where home appliances are repaired and the price is not expensive. If conditions permit, for example, if you have a professional technician, you can also clean up all kinds of foreign objects remaining in the speaker when opening the box: dust, hair, spider webs, all kinds of mosquitoes, flies and moth corpses, etc., as well as wires and electronic components everywhere s contact.