Description

DIY 6J1 Tube Amplifier Kit LM1875 Earphone Output 20W DIY Soldering Project Electronic Kit for Audiophile

The separate transformer power supply needs to be connected to the 220V line, dual AC 12V, 60W, pay attention to safety, pay attention to the purchase of spare parts, pay attention to the model of the triode: B647 D667, LM1875 The two power amplifier tubes need to be insulated, with a white rubber ring Pay attention to install. If you can't read the resistance and don't have a multimeter, you need to contact me to mark the resistance value. No circuit diagram is provided. The output of this amp is very quiet and there is no manual. The finished kit does not include a transformer, and the transformer needs to be purchased additionally. The shell needs to be installed by yourself, and there is a piece of paper on the surface that needs to be torn off, which is the transparent acrylic shell.

Note: The kit parts and finished products are tested without transformers and enclosures. Electronic tubes are issued randomly. 6J1 and 6J2 are common. If you need to specify electronic tubes, please leave a message. If you mind, please do not shoot. Thank you for your understanding.

Increase the heat sink width 76* height 21* length 50mm The heat sink of other stores is width 76* height 21* length 30mm.

This product uses 6j1 or 6j2 electronic tube as the pre-amp to promote the lm1875 power amplifier, with amp function. After 6j1 or 6j2

After the electronic tube buffers, it can greatly reduce the "digital smell" and "transistor sound", so that the whole sound system brings a sweet and natural "bile smell", and the sound is sweeter and softer. Better than the general lm3886, tda7294.

The pre-stage adopts the 6J1 fever electronic tube tube pre-stage: the circuit principle design of the famous machine music fax X-10D, with reasonable optimization, the performance is more stable than the original machine, and the performance of the electronic tube is improved by 10%. This machine adopts dual AC AC12V input, so you don't have to worry about finding a high-voltage power supply.

The working principle of the power supply: as soon as the power is turned on, the tube filament starts to heat up. At this time, the boost voltage starts to boost from zero voltage. When the tube filament is hot, the boost is just finished, so this is the same as the tube rectifier. 4 470UF The capacitor filter is very clean, and the excellent power supply system will not have hum. The filament is powered by DC 12V, and the filaments of two tubes need to be connected in series. The DC filament is also used to reduce noise.

After the output of the front stage, it will automatically switch to push the headphones or push the lm1875 power amplifier of the rear stage, that is, after plugging in the headphones, the power amplifier has no output, and when the headphones are not plugged in, it pushes the power amplifier output.

Amp/pre-output function: Some friends hope that this product can directly drive headphones, and the 6j1 tube pre-output signal can also drive headphones, but the output sound is slightly smaller than that of digital audio sources, and the thrust is average. If friends can accept this method, Then you can give it a try. After the sound source of this product is processed, the sound of the earphones will also have a sweet and delicate "flavor". The headphone output function can also be used as the pre-stage output function, and can be connected to other post-stage power amplifiers.

Post-stage lm1875t power amplifier: Adopt the classic design of European and American LM1875T! The wiring is reasonable! Outstanding performance! Highly sought after by DIY enthusiasts! The shop retains all the original wiring, and under the premise of retaining the original performance, the original components have also been strengthened. After the introduction of 6j1 electronic tubes, the sound is more sweet and beautiful!

Fever materials: Coupling capacitors use Japan's Nissei audio special electrodeless film capacitors, high-frequency low-resistance electrolytic capacitors, 1% precision metal film resistors, Beijing J-level military-regulated electronic tubes 6J1 or 6J2, nichicon, elna fever supplement capacitors, better performance , the sound is better!

Performance parameters:

Power supply voltage: default dual AC 12v/current 3A, power above 60w (the highest voltage cannot exceed dual AC 19V, otherwise the tube will not light up and the sound will be distorted. If you need to use AC 18v, you need to modify the filament step-down resistance to 47 ohms, at this time Amplifier output power will be slightly higher)

Headphone amplifier/pre-stage output: the magnification is about 0.8 times (the headphone amplifier function can be tried, it can push the headphones with high sensitivity, the thrust is average, the headphone amplifier output can also be used for the current stage function, the output is connected to other power amplifiers, and it has the taste of electronic tube. )

lm1875t amplifier output power: typical 20W (maximum 30W)

Speaker impedance: 4Ω-8Ω

Total harmonic distortion: <0.04%

Signal-to-noise ratio: 105dB

Frequency response: 14Hz-100kHz (the maximum range is 3.29Hz-482.29kHz calculated by the RC high and low pass circuit)