凯明这家公司的功放我之前曾经是测过的,当时还在评论区和开发者在评论区一开始”双方交换了意见“然后”增进了双方的了解“”会谈是有益的“最后变成了”亲切友好的交谈“可谓网站与制造商之间互动的一个较好的范例。前些时候我又收到了读者寄测的KM800这台机器:
![Photo Photo](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/Photo-8-1024x683.jpg)
机器的外壳比较普通,特色是1.25MHZ的开关频率和ET/S1两套调音(后面接在ET/S1口的时候可以切换)小5000的价格倒是真的不算很贵,开始测量吧:
![4R5WDashboard 4R5WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R5W-1024x560.jpg)
![8R5WDashboard 8R5WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R5W-1024x560.jpg)
4欧姆的各种功率仪表板如下:
![%title插图%num 4R1WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R1W.jpg)
![%title插图%num 4R5WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R5W.jpg)
![%title插图%num 4R10WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R10W.jpg)
![%title插图%num 4R20WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R20W.jpg)
![%title插图%num 4R50WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R50W.jpg)
![%title插图%num 4R100WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/4R100W.jpg)
8欧姆的各种功率仪表板如下:
![%title插图%num 8R1WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R1W.jpg)
![%title插图%num 8R10WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R10W.jpg)
![%title插图%num 8R20WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R20W.jpg)
![%title插图%num 8R50WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R50W.jpg)
![%title插图%num 8R100WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R100W.jpg)
![%title插图%num 8R200WDashboard](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/8R200W.jpg)
![Dynamic-Range Dynamic-Range](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/Dynamic-Range-11-1024x384.jpg)
![THD+N-Ratio-vs-Freq-@-8R-5W THD+N-Ratio-vs-Freq-@-8R-5W](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/THDN-Ratio-vs-Freq-@-8R-5W-1024x832.jpg)
![SMPTE-Ratio-vs-Measured-Level SMPTE-Ratio-vs-Measured-Level](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/SMPTE-Ratio-vs-Measured-Level-2-1024x882.jpg)
![Multitone Multitone](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/Multitone-7-1024x825.jpg)
![THD+N-Ratio-vs-Measured-Level-ALL THD+N-Ratio-vs-Measured-Level-ALL](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/THDN-Ratio-vs-Measured-Level-ALL-1024x409.jpg)
开关频率确实是1.2MHZ左右:
![%title插图%num 1MFFT](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/1MFFT-1024x541.jpg)
![%title插图%num FFT-Spectrum](https://cdn.l7audiolab.com/wp-content/uploads/2022/04/FFT-Spectrum-1024x541.jpg)
总结:比起之前的 PA800DH有进步,尤其是1.25M的开关频率确实达到了。但也还是保留了PA800DH的传统,带着前级板情况下测量参数不咋地。
胆味功放,听起来确实像胆机……
嗨嗯德amplifier
比昨天的自己有进步,就是好事儿
啥功放IC能去到这么高开关频率……神了
虽然谐波看起来像是那么回事,但是噪声看起来还是很奇怪,这胆味不是很纯净啊
好久没过来逛这个平台了,关于这个胆味前级测试指标不好的问题,大家再相互交流一下,这个胆味电路的作用就是在基波的基础上产生二次谐波及多次谐波,基波电平为0dB的时候,会叠加产生-65dB的二次谐波,(是故意调出来的,可以通过前级板的微调电位器调整),因为谐波成分比较多,所以指标不会好到哪里去,如果指标好,那么就失去了调味的作用。当然这个电路的总谐波失真调到0.005%也是没问题的,我们做产品是希望用户在实际使用中效果满意,把它理解成美颜相机就好,开美颜拍出的照片更讨人喜欢。打个比方,有韵味的电子管功放,无后级反馈的达萧功放等测试指标都不好的,但他们的音质也很讨一些发烧友的喜欢,这种特殊的电路不适合用测试指标去衡量它在实际使用中的好与坏,只能说它的测试指标确实很烂!
其实主要问题是 低频噪声……多了些
感谢教受的指点,功放是62倍放大倍数的,任何前级不人为屏蔽或软静音处理,把噪音放大62后再测试都难理想的,这种高阻抗的JFET电路,弱偏置电流的,我也折腾了几年,设计了十多个版本才做到这水平,尽力了,接音箱帖耳朵听通常是听不到噪音的。
还有一个问题,请问测试指标是直通(S1)测的还是电子管(ET)测的呢?看失真度比之前老款的PA800DH还差不少,同样的环境条件,我们这边测试直通模式时比旧版本的失真度低了5倍左右
应该是S1测的 (具体忘了 真的太久)