What is a preamplifier?

What is a preamplifier? 

What is a preamplifier? It could be difficult to tell, the official explanation was below.

A preamplifier is the role of audio amplification, generally because audio signals are very small and cannot drive power amplifier directly, you must install a front voltage amplification circuit to amplify signal then drive power amplifier. Also, due to the diversity of input signals, such as input signal voltage level, as well as high and low input impedance, a preamplifier will fit to the strength of the input signal to set up a different magnification time. And if internal resistance doesn’t match between signal sourcing and amplifier, it makes to lose a dynamic frequency response, details! Besides adjusting the volume, active preamplifier also can be used for preliminary amplifier, reduce internal resistance difference between the signal sourcing and power stage, which is used as a buffer.

Finally, because varieties of users have various audio sources, output signal amplitude and impedance that less people actually study, there is a big difference at listening actual sounds, on the one hand it is audio output signal amplitude is different, on the other hand is internal resistance  mentioned above. This has created more songs we heard was substantially compress it’s dynamic, and detail is lost, frequency response is attenuated. Very apparently we were using computer or cell phone to connect power amplifier when listening to some music, it doesn't even feel to the low frequency and high frequency is not so bright small volume situation. No matter how good computer sound card and how good the sound system, it could not find the original tapes of the time!

Here, 6N2 tubes we used the most common one, we specifically tune the circuit for computer sound source without expensive components piled up, but a reasonable configuration, we choose the most suitable work point, and precisely matched the key components to ensure circuit work at the best.

Circuit Diagram

More details, please find here!

How To Make A Tube Guitar Amplifier By The Powerful DIYer

How To Make A Tube Guitar Amplifier By The Powerful DIYer

You can see that how he make a tube guitar amplifier form scheme diagram, making the wooden casing and chassis, soldering, assembling, tuning..., and so on through the video.

Finally, get an absolutely customized and great tube guitar amplifier, the guy's DIY skills is wonderful...

Needn't be amplified by Amplifier -- Gaeml's Big Song

Needn't amplify by Amplifier -- Gaeml's Big Song 

Gaeml‘s Song originated in the Spring and Autumn Period in China, has been 2500 years of history, which is a multi-part in the Gaeml region in China , no command, a cappella, folk choral form natural chorus. In 1986, at the Paris Autumn Festival, once the Gaeml‘s Song from Liping of Guizhou Province appeared, was sensational and considered a "spring-like flash of music, passing the edge of the ancient dream of melody."

Needn't be amplified by any amplifiers, you can enjoy pure human songs from these beautiful girls...

Enjoy DIY 300B Tube Anplifier PCBA Kit With Free Testing

A lot of HIFI audiophiles like to do DIY 300B tube amplifier with scaffold-soldering way previously, but that is a great engineering and too much wiring, reliability and performance may be affected, also its appearance does not look good. Now, there are well-made PCBA instead of scaffolding soldering, the problems above will be completely resolved, and it is not difficulties since then. Because the PCBA board is free testing, and its manufacturing difficulties is equal to assemble a LM1875 amplifier. 

You can use this kit to build your 300B tube amplifier.Framework of the 300B tube amplifier kit adopts 6SN7 plus 300 B single-ended outputs. And this 300B PCB material is 2.0 thick double copper immersions gold. Output transformers are made of high-grade silicon steel plate Z11, and used imported electronic vacuum tubes.

3-bands MW / SW Tube Radio with Little 7 Tubes Nostalgia Style

 3-bands MW / SW Tube Radio with Little 7 Tubes Nostalgia Style

In our memories, tube radio was the product of the last century. But from then on, transistors had replaced those tubes, and digital had replaced analogy accordingly, however still some people like tube radio, like its taste, and more like its nostalgia style...

This is a pure tube 3-band radio, it can receive a medium wave and two band shortwave signal. Tube radio is built in 4-inch small speakers, which can meet listening need for 15 square rooms. If you connect an external 6-8 inch full-range speaker, then there will be a leap in sound volume. It has MW / 3-band frequency range: MW: 535-1605 KHZ, Shortwave 1: 2.3-7 MHZ, Shortwave 2: 6-18 MHZ

Little 7 Tubes  3-bands MW / SW Tube Radio

Inside View

If you want to get better listening effect, you will set up a longer antenna that length is about 5 ~ 10m or more and leave it outdoor, this is common sense for tube radio's fans. We set up the antenna as below and get better effect.

1. Outdoor antenna is connected to the fifth floor, which is a about 10 meters aluminum wire with plastic cover for drying clothes, and connected with an ordinary wire led to the second floor studio listening, there is no ground wire.

a) During daytime and it can receive 5 MW stations, in the evening receive more than 10 one. Good listening experience.

b) Short-wave 1: 2.3-7MHZ. receives 2-3 stations in daytime, receives more than 10 stations in evening, the effect can still listen.

c) Short-wave 2: 6-18MHZ. receives more than 10 stations in daytime, receives more than 30 stations in evening, good listening experience.

2. If indoor antenna with ordinary wire 2 meters, listening effect is general.

In order to ensure that the tube radio is original taste and flavor, the old components is used on the unit, most of them came from new inventory of 70-80's of the last century, power transformers is DB -50-300 inventory produced in the 1980s, and output transformer is model CB-3.5W-80, they are produced by Shanghai radio No 27 factory all. And Double variable capacitors, wire wound resistors 4W100Ω, fuse holder is disassemble (but tested and performance is intact), its appearance looks like a little rust; after all they are decades of inventory. Dial has not improved, and this depends on you and the buyer's hands capability.

Main Specifications

1. Equipped with seven tubes: 6A7PJ, 6K3PJ, 6N9PJ, 6H6PJ, 6P6PJ, 6Z5PJ, 6E2M

2. Bass / tremble control

3. Built-in Radio / Phono (CD player) switch

4. Built-in a switch jack between radio speaker and outside speaker.

5. Aluminum chassis Dimensions (L * D * H) 340mm X 200mm X 190mm.

6. Working voltage: 220V / 50Hz

 

More details, please find http://www.aliexpress.com/store/product/Tube-AM-SW-Radio-Little-7-Tubes-3-Bands-Radio-AM-535-1605-KHZ-SW-2/725205_32288122286.html