Condition:New
Type:Logic ICs
LA5 MOS-FET pure nail headphone amplifier Foreword: If you need a headphone amplifier comparable to high level, please read our introduction carefully. If you want to quickly understand the characteristics of LA5, please see the following lines: 1.The ±26V 260mA power supply guarantees the output power of the amp. The amp is first and foremost an amplifier.
2.The perfect combination of OPA2604 + high power field effect tube.
3.The MCU microcomputer controls input switching, gain switching, output impedance switching, and at the same time realizes the full-function headset protection function of the headset.
5.High-end appearance design, full touch button operation.
General parameters: Output power (1KHZ sine wave equivalent undistorted power): 300mW / 600 Euro, 1200mW / 32 Euro.
Signal to noise ratio:> 102dB.
Output impedance: 10 Euro, 47 Euro, 120 Euro can be switched.
Voltage amplification gain: 10 times in standard gain mode and 18 times in high gain mode.
Maximum output voltage swing: greater than plus or minus 13V (equivalent to 26V).
Input interface: Two RCA audio inputs, MCU front panel switch.
Output interface: 6.35 headphone output.
Average power consumption: AC220V <20W.
Volume: 220 * 52 * 191
Net weight: 2.8 kg.
Interface instructions:
Front panel control operation instructions (from left to right)
Power: power switch
InSel: Input selection switch, used to select the two analog inputs of the amp InA, InB
Gain: Gain selection switch, used to select the amp voltage amplification gain
Impedance: output impedance selection switch, used to switch the output impedance of the amp
Phone: Headphone output
Volume: Volume control
2. In addition to the AC220V input and power switch on the rear panel, there are two sets of RCA terminals, which are respectively responsible for the two-way input of the audio source.
Advantages of LA5 MOS-FET
1. Pure Class A circuit, the quiescent current of the last-stage big tube is 260mA! It can eliminate the distortion caused by the power tube switch and the sound is warm. At the same time, it has good damping characteristics and perfect control force.
2. Use OPA2604 fever op amp as a voltage amplification stage. This famous op amp has a unique advantage, that is, it can be powered by positive and negative 24V. This machine uses positive and negative 22V to power OPA2604. The advantage is that the output voltage swing of the amp is greatly increased, which is a prerequisite for driving high impedance (600 ohm) headphones! Also, the OPA2604 op amp can only make a difference under high pressure, which is a consensus among enthusiasts.
3. Adopt high-power field effect tube for current amplification, which works at a positive and negative 26V, 260mA quiescent current to ensure the output power of the amp. The advantages of using field effect transistors are twofold. First, field effect transistors have the inherent advantage of warm sound, and there is no dry digital sound of transistors; second, field effect transistors are voltage-driven components, which can make the driving burden of the op amp fundamental. Reduce, so that the quality of the op amp can be fully utilized.
4. The voltage amplifying stage power supply uses a parallel voltage stabilizing circuit. This circuit is unmatched by any voltage stabilizing circuit. Its low internal resistance, small ripple, and good transient characteristics provide a good foundation for the voltage amplifying stage.
5. Headphones with adjustable gain, different impedances and different sensitivities have different requirements for amp gain. LA5 uses a microcomputer MCU control to switch between high and low gain through the Gain key on the front panel, which is suitable for the needs of different headphones.
6. The output impedance is adjustable. This is a very important point. Many fans believe that the amp should be paired with the headset. For example, Lehman is equipped with HD650, A1 is equipped with DT880, etc. In addition to circuit reasons, the gain and output impedance are A very important point when pairing an amp with headphones. Different output impedances allow the amp to be used for different damping, and the adaptability of the headphones will be higher. In actual tuning, the LA5's mid-impedance output is perfect with HD650 and K601, while the high-impedance output can be well adapted to the 600 Euro DT880.
7. MCU full control, the amp uses a microcomputer to control the output selection, gain selection, output impedance selection of the amp, touch button to switch and has a memory function, at the same time with a complete headset protection function, all are switched by internal relay Even if it is a ten thousand yuan amp, the design is difficult to surpass!
8. Regardless of cost, as long as the sound quality materials:
In order to give the amp an excellent source of power, imported Talema 50VA transformers are used.
Using the best ALPS 27 potentiometer and feverish electronic components, old fans, we know what you understand, but we also know that good components are just the premise of good sound, design and tuning depend on skill!
High-power FETs have better linearity, lower distortion and more power!
See the picture for the workmanship of high-end amps
A few additions:
1.All the components of this amp are targeted design. You should not consider polishing the machine or replacing the op amp. It is especially important because most of the op amps will burn directly under the operation of the LA5 op amp and dual 22V Serious damage to the machine.
2.When you use low-resistance and high-sensitivity headphones, it is recommended to turn off the volume when switching gain or output impedance to avoid sudden loud noise.
3.About the sound quality of LA5, I can only describe it as extremely excellent. Her voice is rich and warm, the sound field is wide, the image is clear, the middle is calm, and the resolution is very good. The DT880 from HD650 to HD800 to 600ohm is tuned. outstanding performance!
