Description
Yaqin MS-30L is the revised version of the amplifier Yaqin MS-20L. As in the previous model, the amplifier operates in push-pull, which is based on the same tubes as the predecessor of which is 2 EL34-B power tubes per channel and 4 tubes 6J1 control of the cannnel. This design allows to work in two modes: triode and ultra linear – pentode (selection of working mode from the front panel or the remote control). The amplifier has a headphone plug located on the front panel.
Triode mode – power tubes pentode work as a triode without local feedback while maintaining good linearity which is characteristic of the triode structure.
Ultra linear mode – power tubes work as pentode using local feedback ratio of speaker transformer tap on the pentode grids . In this mode, thanks to the multi grids tubes obtain higher efficiency and expanding bandwidth.
High DC voltage delay circuit to protect tubes .
It’s very important to maintain the stability and accuracy of the operating points of the tube amplifier, especially of the power tube. The screen current changes when the tube gets ageing, or replacing the tube. Break away of the required operating points will influence sound resolution and the stability of the machine. So, please check and adjust the screen current after a long time of use, and it is the same when changing the tube.
Methods of Measurement of the TUBE BIAS VOLTAGE
Use a multi-meter to measure. Adjust the multimeter to volts d.c. 1V range, and the volume of the amplifier the minimum, then insert the anode of the multi-meter pen into the positive hole, and the cathode into the negative hole respectively. The bias voltage should be about 0.45V when the standard input voltage is 230V or 115V.
Main Freatures:
- The latest version of EL34 output amplifier from Yaqin;
- Infrared remote control for volume adjustment and input selections;
- TR/UL (Triode and Ultra Linear modes) switches on the front panel;
- Earphone jack on the front panel;
- External bias adjustment;
- High DC voltage delay circuit to protect tubes;
- Class A push-pull power amplifier to reduce distortion;
- Output transformers manufactured with Japanese silicon steel sheet and high-quality enamelled wire, which offer a wide dynamic range at full rated output;
- Utilizes the audiophile capacitors and high quality metal precision resistors dedicated for audio frequency;
- Applies special potentiometer as volume controller with low noise, and durable;
- Beautiful heavy duty chassis. Aluminum chassis top, front panel, and bezels, stainless steel chassis, and steel bottom;
Specification:
- Output Power: 50W per channel (8Ω)
- Valve / Tube: EL34B × 4, 6J1 × 8
- Frequency: 5Hz ~ 75KHz
- Signal/Noise Ratio: >88dB (A weight)
- Earphone Output: 32Ω
- Ohms: 4 – 8 ohms
- Distortion Harmonic: ≤1.6% (at 1KHz)
- Input Sensitivity: 0.23V(1KHz)
- Power Consumption: 180W
Power Specification :
雅琴MS-30L是雅琴MS-20L放大器的修订版。与以前的模型一样，该放大器以推挽方式工作，该推挽基于与前者相同的电子管，每条电子管有2个EL34-B功率管，并且通道的控制有4个电子管6J1。这种设计允许在两种模式下工作：三极管和超线性-五极管（从前面板或遥控器选择工作模式）。放大器的前面板上有一个耳机插头。
三极管模式-功率管五极管在没有本地反馈的情况下充当三极管，同时保持良好的线性度，这是三极管结构的特征。
超线性模式功率管利用五极管栅极上扬声器变压器抽头的局部反馈比作为五极管工作。在这种模式下，由于采用了多网格管，因此可以获得更高的效率并扩展了带宽。
高直流电压延迟电路保护灯管。
保持电子管放大器，尤其是功率管的工作点的稳定性和准确性非常重要。当灯管老化或更换灯管时，屏幕电流会改变。脱离所需的工作点将影响声音的分辨率和机器的稳定性。因此，长时间使用后，请检查并调整屏幕电流，更换灯管时也是如此。
TUBE BIAS电压的测量方法
使用万用表进行测量。将万用表调整为d.c.在1V范围内，并且放大器的体积最小，然后将万用表笔的阳极分别插入正极孔中，并将阴极分别插入负极孔中。当标准输入电压为230V或115V时，偏置电压应约为0.45V。
主要特征：
雅琴EL34输出放大器的最新版本；
红外遥控器用于音量调节和输入选择；
前面板上的TR / UL（三极管和超线性模式）开关；
前面板上的耳机插孔；
外部偏置调整；
高直流电压延迟电路可保护灯管；
A类推挽功率放大器，以减少失真；
由日本硅钢片和优质漆包线制成的输出变压器，在满额定输出时提供宽广的动态范围；
利用发烧电容和高品质的金属精密音频电阻器；
采用专用电位器作为音量控制器，噪音低，经久耐用；
美丽的重型底盘。铝制机箱顶部，前面板和挡板，不锈钢机箱和钢制底部；
规格：
输出功率：每通道50W（8Ω）
阀/管：EL34B×4，6J1×8
频率：5Hz〜75KHz
信噪比：> 88dB（A重量）
耳机输出：32Ω
欧姆：4-8欧姆
失真谐波：≤1.6％（在1KHz时）
输入灵敏度：0.23V（1KHz）
消耗功率：180W
电源规格：
输入电源: 110V-240V
每通道输出功率: 50W（8Ω）
阀/管: EL34B×4，6J1×8
频率: 5Hz-75KHz
信噪比: > 88dB（A重量）
耳机输出: 32Ω
欧姆: 4-8欧姆
输入连接器: 四组镀金隔离式RCA连接器（AUX1-AUX4）
失真谐波: ≤1.6％（在1KHz时）
输出连接器: 两个通道，两组镀金插孔
输入灵敏度: 0.23V（1KHz）
消耗功率: 180W
包装包括：
所有电子管，遥控器，电源线1.5m，六角螺丝刀，螺丝刀，保险丝，遥控器电池。
