At the beginning of the year, the "Ange" brand of Lici Foshan Audio Studio launched its first preamplifier, a real direct-heated 2A3 vacuum tube front stage, the model is AS-133. As soon as it was launched, the first batch of products were sold out.

Thank you very much for your support. In the process of actual use and purchase, many enthusiasts asked a few key questions that they were interested in. Then, we will answer them one by one.

1 ) What are the sound characteristics of this preamp?

This pre-stage uses a direct-heated three-stage 2A3 electron tube for amplification. Originally, 2A3 can be used as a low-power 3W power amplifier. When used in the front stage, we hope to have the control power and sense of space of a direct heating transistor, with fine high-frequency extension, rich sound details, and full and moist mid-frequency. However, after years of experience accumulation, "big" sounds better than "small", but it is much more difficult to adjust the production design to "big" than "small". This is also the reason why there are relatively fewer varieties of such pre-stages on the market.

Sound is the most subjective thing, and everyone's preferences are different, but "natural, true, and vivid sound reproduction characteristics" have always been the pursuit of the Ange brand. Large current, large driving force; improve the original sound system's thin and fuzzy sound problems, the sound is full, moist and transparent; the sense of space is more three-dimensional and full, and the wide sound field is the sound characteristic of this machine.

This pre-stage three-band is balanced and durable, and it is also a great platform for testing vacuum tubes. When different 2A3 tubes are replaced, the sound characteristics of each tube can be immediately distinguished. You can choose your favorite vacuum tube to replace it. We recommend RCA's 2A3 tube. The performance of the extremely high and very low frequency bands is much better. Of course, you can also choose the old 45 tube of the last century. The intermediate frequency will be very brilliant, and there will be unexpected gains with 3/5A.

2 ) Why do we need to set 6 groups of gain adjustments? What's the point of doing this?

Many post-stages on the market do not have input level adjustment, and most of them are high-gain post-stages. In theory, the benefits of a suit may be reflected in the good gain matching between the front and rear stages.

However, many friends' home systems are selected according to their own preferences. The front and rear stages may not be the same suit. Sometimes the front stage volume is slightly increased, and the sound will be overloaded and distorted. We discovered this problem during the actual return visit to the customer's home. At this time, the 6-group gain matching design of the AS-133 front stage is very valuable, and the adaptability and playability are very high. It can do -6, -4, -2, 0, +2, +4 according to the output level of your front and rear output devices, the sensitivity of your speakers, and the size of the room and the acoustic characteristics of the space. Level adjustment, tune out the sound that makes you more satisfied.

The six sets of gain design use a volume transformer, and the gain adjustment is realized through the tap winding of the transformer. The front-end audio source and the back-end power amplifier have six more adjustments, and the adaptability is greatly improved. After you carefully adjust , when the sound signal passes, it will turn from the throat path into a highway, and the sound will be more balanced and smooth.

3 ) Is the knob at the center of the front panel a volume knob? How to use it?

The upper left corner of this machine is the input volume knob, and the knob in the middle of the front panel is the stepping output volume knob.

The input volume knob is in the upper left corner of the front panel, which is smaller than the middle knob and has a different shape. Don't make any mistakes. The input volume can be easily controlled by the remote control on the panel, and the mute state can be turned on or off by the remote control when receiving and calling the mobile phone.

The stepped output volume knob in the middle is set according to the equipment and space characteristics of your house, with 6 sets of gain adjustments. After receiving this pre-amp, our customer contacted me after listening to it for a few days, "How do you feel that the sound is so small? The sound of the Stranda is much smaller than before, is there a problem with the pre-amp." I found out after patiently inquiring He turned the middle stepping output volume knob only to the ten o'clock position. I asked him about the size of the space and the configuration of the equipment. I suggested that he turn the knob clockwise to the end, and then dial 2-3 divisions. The gain adjustment later uses a flat-blade screwdriver to turn it to the 0 position ("0" is Standard gain, ten times magnification). After resetting, the customer replied to me "sound quality-reborn"! Of course, if we listen patiently, we can use multiple music records of different styles, and we can make more detailed adjustments. If we put it in the "-2" position, will there be more sound details, and the "+2" position high frequency Will it be more refined, …………. After this stepping output volume knob is combined with 6 sets of gain adjustment settings, the changes are endless, there is always a sound you want.

4 ) What method is used for rectification of this front stage?

The AS-133 front stage is designed and manufactured by manual scaffolding and welding, using 5U4 (274B) bladder rectifier, the filtering part is more perfect, the power supply is more stable, and the bile is full. Low-frequency elasticity, sound space, warmth and other aspects are well represented. If you plan to replace it with the first one, we recommend replacing it first. A NOS tube of several hundred yuan will bring obvious sound improvement.

5 ) Can this meter detect the working status of the 2A3 tube?

The watch head design has always been the basic configuration of the Ange brand's appearance design, full of nostalgia. But in order to ensure the sound quality, our front end does not detect the working status of the 2A3 tube. It detects the working status of the 6SN7 tube in conjunction with the button on the right. It is convenient to change the tube in time when the tube is found to be aging.

6 ) Is the balanced input truly balanced? Why not do true balanced output?

Everyone knows that it is rare for vacuum tube machines to achieve true balanced input and output, and it is not easy to achieve. Of course, some machines will provide balanced interfaces.

This AS-133 before the song taian stage uses a balancing transformer design, the use of costly engraved Western Electric 618 input cattle, to achieve true balanced input into.

Our Ange AS-123 bladder buffer can be connected between the front and rear stages to achieve true balanced input and true balanced output. When used together, it complements each other and avoids duplication of investment.