People who love good music probably know about the Hi-End tube amplifier. You can make it yourself if you know how to use a soldering iron and have some knowledge of working with radio engineering.
Unique apparatus
Hi-End tube amplifiers are a special class of home appliances. What is it connected with? Firstly, they have a rather interesting design and architecture. In this model, a person can see everything that he needs. This makes the device truly unique. Secondly, the characteristics of the Hi-End tube amplifier differ from alternative models that use transistor-integrated circuits. The difference between Hi-End is that the minimum number of parts is used during installation. Also, when evaluating the sound of this unit, people trust their ears more than the harmonic distortion measurements and the oscilloscope.
Selecting schemes for assembly
The pre-amplifier is fairly easy to assemble. For it, you can choose any suitable scheme and start assembling. Another case is the output stage, that is, a power amplifier. With it, as a rule, there are manyvarious questions. The output stage has several assembly types and modes of operation.
The first type is a single-cycle model, which is considered a standard cascade. When operating in the "A" mode, it has a small non-linear distortion, but, unfortunately, has a rather poor efficiency. Also note the average power output. If you need to fully sound a fairly large room, you will need to use a push-pull power amplifier. This model can work in "AB" mode.
In a single-cycle circuit, only two parts are enough for a good operation of the device: a power amplifier and a pre-amplifier. The push-pull model already uses a phase reversing amplifier or driver.
Of course, for two types of output stages, in order to work comfortably with an acoustic system, it is necessary to match the high interelectrode resistance and the low resistance of the device itself. This can be done with a transformer.
If you are a connoisseur of "tube" sound, you should understand that you need to use a rectifier, which is produced on a kenotron, to achieve such a sound. Do not use semiconductor parts.
When developing a Hi-End tube amplifier, you can not use complex circuits. If you need to sound a fairly small room, then you can use a simple one-stroke design that is easier to make and set up.
DIY Hi-End Tube Amplifier
Before starting installation, you need to understand some rules for assembling such devices. We will needapply the basic principle of mounting lamp fixtures - minimizing fixtures. What does it mean? You will need to discard the mounting wires. Of course, this cannot be done everywhere, but their number must be minimized.
A good Hi-End tube amplifier uses mounting lugs and straps. They are used as additional points. Such an assembly is called hinged. You will also need to solder the resistors and capacitors that are on the lamp panels. It is strongly discouraged to use printed circuit boards and assemble conductors in such a way that parallel lines are obtained. This way the assembly will look chaotic.
No Interference
Later, you need to eliminate the low-frequency background, if, of course, it is present. Also important is the choice of grounding point. In this case, you can apply one of the options:
- Connection type - star, in which all "earth" conductors are connected to one point.
- The second way is to lay a thick copper bus. It is necessary to unsolder the corresponding elements on it.
In general, it is better to find a grounding point yourself. This can be done by determining the level of low-frequency background by ear. To do this, you need to gradually close all the grids of lamps that are located on the ground. If, when the subsequent contact is closed, the low-frequency background level decreases, then you have found a suitable lamp. To achieve the desired result, it is necessary to experimentally eliminate unwanted frequencies. Alsoyou need to apply the following measures to improve the quality of your build:
- To make the filament circuits of radio tubes, you need to use twisted wire.
- Tubes used in the preamplifier must be covered with earthed caps.
- It is also necessary to ground cases with variable resistors.
If you want to power the pre-amp tubes, you can use direct current. Unfortunately, this requires the connection of an additional unit. The rectifier will violate the standards of a Hi-End tube amplifier as it is a solid state device which we will not be using.
Transformers
Another important point is the use of different transformers. As a rule, power and output are used, which must be connected perpendicularly. In this way, you can reduce the level of low-frequency background. Transformers should be located in earthed casings. It must be remembered that the cores of each of the transformers should also be grounded. You do not need to use shielded wire when you install devices, so that there are no additional problems. Of course, these are not all the features associated with installation. There are quite a lot of them, and it will not be possible to consider them all. When installing a Hi-End (tube amplifier), you cannot use new element bases. They are now used to connect transistors and integrated circuits. But in our case, they will not work.
Resistors
High-end high-end tube amplifier is a retro device. Of course, the parts for its assembly must beappropriate. Instead of a resistor, a carbon and wire element may be suitable. If you spare no expense to develop this device, you should use precision resistors, which are quite expensive. Otherwise, MLT models are applicable. It's a pretty good item, as evidenced by the reviews.
Hi-End tube amplifiers are also applicable with BC resistors. They were made about 65 years ago. Finding such an element is quite simple, just take a walk around the radio market. If you use a resistor with a power greater than 4 watts, you need to choose enameled wire elements.
Capacitors
In the installation of a tube amplifier, you should use different types of capacitors for the system itself and the power supply. They are usually used for tone control. If you want to get high-quality and natural sound, you should use a decoupling capacitor. In this case, a small leakage current appears, which allows you to change the operating point of the lamp.
This type of capacitor is connected to the anode circuit, through which a large voltage flows. In this case, it is necessary to connect a capacitor that supports a voltage of more than 350 volts. If you want to use quality elements, you need to use Jensen parts. They differ from analogues in that their price exceeds 3,000 rubles, and the price of the highest quality radio elements reaches 10,000 rubles. If you use domestic elements, it is better to choose between the models K73-16 and K40U-9.
Single Strokeamplifier
If you want to use a single-cycle model, you must first consider its circuit. It includes several components:
- power supply;
- end stage;
- a pre-amplifier in which you can adjust the tone.
Assembly
Let's start with the pre-amplifier. Its installation takes place according to a fairly simple scheme. It is also necessary to provide for power control and a separator for tone control. It must be tuned to low and high frequencies. To increase the shelf life, you need to apply a multi-band equalizer.
In the laughter of the pre-amplifier, one can see similarities with the common 6N3P double triode. The element we need can be assembled in a similar way, but using the final cascade. This is also repeated in stereo. Remember that the design must be assembled on a circuit board. First it needs to be debugged, and then it can be installed on the chassis. If you have installed everything correctly, the device should turn on immediately. The next step is to move on to the settings. The value of the anode voltage for different types of lamps will be different, so you will need to select it yourself.
Components
If you do not want to use a quality capacitor, you can use K73-16. It is suitable if the operating voltage is more than 350 volts. But the sound quality will be noticeably worse. Electrolytic capacitors are also suitable for this voltage. Connect to an amplifieroscilloscope S1-65 and send a signal that will pass from the audio frequency generator. When initially connected, you need to set the input signal to about 10 mV. If you need to know the gain, you will need to use the output voltage. To find the average ratio between low and high frequencies, you need to choose the capacitance of the capacitor.
You can see a photo of the Hi-End tube amplifier below. For this model, 2 lamps with an octal base were used. A double triode is connected to the input, which is connected in parallel. The final stage for this model is assembled on a 6P13S beam tetrode. This element has a built-in triode, which allows you to get a good sound.
To set up and check the performance of the assembled device, you must use a multimeter. If you want to get more accurate values, then you should use a sound generator with an oscilloscope. When you have taken the appropriate devices, you can proceed to the setting. On the cathode L1 we indicate a voltage of about 1.4 Volts, this can be done if you use the resistor R3. The output lamp current must be specified as 60 mA. To make a resistor R8, you need to install a pair of MLT-2 resistors in parallel. Other resistors can be of different types. It should be noted a rather important component - the isolation capacitor C3. It was not in vain mentioned, since this capacitor has a strong influence on the sound of the device. Therefore, it is better to use a proprietary radio element. Other elements C5 and C6 - filmcapacitors. They allow you to increase the quality of the transmission of various frequencies.
A power supply built on a 5Ts3S kenotron is worth finding. It complies with all the rules for constructing the device. A homemade Hi-End tube power amplifier will have high-quality sound if you find this item. Of course, otherwise it is worth looking for an alternative. In this case you can use 2 diodes.
For a Hi-End tube amplifier, you can use the appropriate transformer that was used in the old tube technology.
Conclusion
To make a Hi-End tube amplifier with your own hands, you must perform all the steps consistently and accurately. First, connect the power supply with an amplifier. If you set up these devices correctly, you can mount a preamplifier. Also, using the appropriate technique, you can check all the elements to prevent damage to the speaker system. After assembling all the elements together, you can proceed to the design of the device. Plywood might work well for the body. To create a standard model, it is necessary to place radio tubes and transformers on top, and regulators can already be mounted on the front wall. With them, you can enhance the tone and see the power indicator.
