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SABRE A28是四路独立放大电路组成的全平衡甲类耳机放大器,拥有齐全的接口:输出包括两组6.35非平衡接口,平衡双三芯接口以及平衡四芯接口。输入则具有RCA以及平衡接口,可以方便的连接音源和各种不同接口的耳机。
SABRE A28的电路设计,整体布局以及零件选择是由多年的设计及听音经验所决定的。电路基本结构为运放驱动菱形交叉缓冲(钻石缓冲)。在试验了几十种从经典的5534到最新的运放之后,我们选定了OPA2604,因为我们觉得在这个设计中他的声音最平衡。输出管采用MJE243/253中功率管。
其他的地方也经过深思熟虑:加拿大Plitron高品质环牛供电,平衡/不平衡输入由继电器控制选择,不平衡输入使用OPA1632转换成平衡信号。音量使用台湾ALPHA四联电位器控制,平衡接插件全部是纽催克,所有元器件的选用和电路参数经过充分严谨设计调校,反复长时间聆听,拥有极高的性能和优秀的听感。
外壳由铝合金材料精加工制成,小巧的体积:(250*200*60mm)体积和钰龙韵SABRE D系列产品搭配兼容,例如SABRE DA8解码可以很方便的组成西装搭配,机器的散热孔位于两侧,使用时注意两侧能有空气流通。
使用注意:使用平衡输入可以得到更好的性能,通过后面板开关选择输入信号.前面板的两个耳机插孔是双用插孔,可以连接双三芯平衡耳机,也可以连接6.35接头的普通耳机.四芯平衡输出仅能连接四芯平衡耳机,不可通过转接头连接单端耳机,否则会损坏机器.
通用建议: A28输入端尽可能不要同时接上RCA信号线和平衡信号线,因为这样会导致平衡地线和RCA地线之间造成共地干扰,在RCA输入时会降低音质(此建议适用于所有的平衡耳放,不仅仅是A28)
A28 is a fully balanced class A headphone amplifier constructed by 4 amplification channels. Its complete connections are convenient to connect source and headphones with different terminals.
Outputs:
- Unbalanced 6.35mm, 2 sets
- Balanced 3 pin XLR
- Balanced 4 pin XLR
Inputs:
- Unbalanced RCA
- Balanced XLR
The circuit, construction and components are fine tuned and selected over years of design and listen experience, aimed for best sound quality within a certain cost, and not just use hifi grade parts in blind. The amplification is OPAMP driven complementary transistor buffer (also known as “Diamond Buffer”). After trying dozens of OPAMPS – from pristine NE5534 to the latest offers from major manufacturers, OPA 2604 was chosen because we feel it sounds most balanced in this particular design. The output is MJE243/253 middle powered transistor.
Other details include: Plitron power transformer from Canada, Neutrik XLR connectors, and Alpha 4-gang potentiometer made in Tai Wan. Unbalanced inputs are converted to balanced signal by an OPA1632, and the balanced/unbalanced input selection is done by a group of relays to optimize signal path.
The precisely machined aluminum mini case is same foot print as Saber D series: 250*200*60mm. So it is easy to part with those products such as a DA8 to make a complete set. Please note that there are cooling vents at the side of the machine, and please keep free air flow near those vents.
Use note: use balance input can get better performance , Input signals from the rear panel switch selection. Two headphone jacks of the front panel is double jack, can connect double 3 pin balance headphones, also can connect 6.35 headphones. 4 pin balanced output can only be connected 4 pin headphones, not through the connector to connect unbalanced headphones, otherwise it will damage it
Please be noted, if you use a same source to feed A28, do not connect the RCA and XLR interconnects altogether. This will cause common ground interference and degrades the performance of the RCA input signals. (This applies not only to A28 but other similar products in our tests).
Practical Performance:
●SNR:>120dB
●THD+N: 0.0005%
●Crosstalk >100dB
●Frequency response:20-20KHz-0.3dB
●Balance output power :600ohm:400mW 300 ohm:700mW 150 ohm:1.3W 32 ohm:2.5W
●unbalance output power: 600ohm:120mW 300 ohm:200mW 150 ohm:350mW 32 ohm:800mW
●Power Consumption: <30W.
●Dimensions: 250*200*55mm.
● Weight: 3Kg.
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