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本帖最后由 大尾鱼 于 2012-7-6 10:47 编辑
回复 1# 叶荣玉
在下完全赞同上述观点。人的那双耳朵就是那么奥妙!那么难待候!
美国的音响设计大王,JC, 昨天(7月4曰)也刚好发表了相关的话题。在下试转译如下:
1970年我犯了我一生的第一个大设计错误;它是有关使用电容器,…。当年为GD公司研制一台晶体管的录音坊控制台,我们已经选择了我们可以找到的最优质的IC:哈里斯911,它可以工作在+ / - 24V,驱动600欧姆的负荷,有+5 / -2.5V /us 的压摆率或电压转换速率(Slew Rate)。当年,一个非常优秀的IC啊。我的同事发现了一些2UF的瓷介电容。因为它的大小合适,而將它用作耦合电容。我们做好了电路板,测试过关。再用当年的80 MHz,SMPTE分析的测试,它也OK。
然而,GD公司对我们这个控音台仅作了一小段时间的评估后,决定放弃了我们的设计,又回到了胆机。我也失业了。这是我一个严重的教训。像工程师般地去设计产品,使样样指标符合传统规范,这并不一定可造出一个被人接受的音响产品。后来,很久以后,是相当长的一段时间后,我才意识到,首先是瓷介电容(瓷介电容几个字作者用大写作强调),其次是IC集成电路,毁了这台机的音频质量。即使拥有上好的测试设备,我仍然是无法(无法二个字作者用大写作强调)法测量或找到设计上的错误。
(在下注:难怪在JC,他的出名作品中,如JC-1, JC-2…等等,他极少使用耦合电容,更不纳用IC。)
英文全文如下:
john curl
diyAudio Member
Yesterday, 05:52 PM #24182
I made my first BIG mistake using capacitors in 1970, designing a solid state studio board for the GD. We had already chosen the highest quality IC that we could find: The Harris 911, that could operate at +/- 24V, drive 600 ohms, and had the slew rate of +5/-2.5 V/us. Pretty darn good for an IC at that time. My associate found some 2uf CERAMIC caps that were the right size for coupling between stages. We built the board, it tested OK, (at the time I only had an SMPTE IM analyzer) and an 80 MHz scope. Still, it seemed to work OK.
However, when it was evaluated by the GD over a period of time, they went back to tubes, and I went back to being unemployed. This taught me a serious lesson. Designing like an engineer, and meeting traditional specs, did NOT necessarily make an acceptable audio product. Later, much later, like a few years later, I realized that the CERAMIC caps, and secondarily the IC's, had ruined the audio quality, and I COULD NOT measure the problems with the test equipment that I then had very well. |
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