JLH1969 MOSFET Class A/AB amp

wzy728

楼主的IP是美国/加拿大的,肯定是外籍人士啦~
谢谢HASSAWY兄的翻译~
没别的表示,也加点分吧~

ateast99

原帖由 millwood 于 2007-10-24 04:57 发表
By the way, R8 is a variable resistor and R2 can also be a variable resistor.

R8 is used to adjust idle current (adjusted so that the voltage drop on the RE resistors is about 25mv), and R2 us ...

请问这个RE是哪个电阻啊？如果带8偶负载的话要调整相应的电阻阻值吗？

大江626

RE应该是射极电阻也就是说是哪两个0.22的 R5 R6 这两个电阻上的电压是25mv 也就是说末级静态电流是 114ma

millwood

quite a few people have asked that what simulator I was using.

it is switchCAD, by Linear. it is freely downloadable at Linear.com (http://www.linear.com/designtools/software/switchercad.jsp). click on "No thanks ...".

save it and then do an install.

very simple, and effective. However, it doesn't have a lot of devices (other than Linear's products) but good enough for most of our work.

I will upload the jlh1969 mosfet simulation file tomorrow for everyone to play with.

音响DSP

JLH电路不错，但是功率不够，在福建科学技术出版社的《胆石功放设计》里有提到，此君可是音响界巨匠级人物，建议大家去看看这个本，翻译得还不错了，对大家仿制NAP和Aura有很大的帮助。

ateast99

昨天洞洞板做了1声道，功率不如三极管的大，但是确实如楼主所说，一点也不热，只有C2073有大概40多度的温度，530基本是凉的，但是开到最大声音源不播放的时候，喇叭里有“次~次~次~”的声音，间隔大概1秒左右，不知道何故啊

bj1876

不懂Ｅ文， 看着头晕

ateast99

44楼的意思是很多人问他用的啥模拟器，他说用的这个switchCAD，这个http://www.linear.com/designtools/software/switchercad.jsp是下载地址，虽然里的器件不多也够用了，还有就是明天上1969MOS版的图。。大家一起玩

millwood

原帖由 ateast99 于 2007-10-26 13:30 发表
昨天洞洞板做了1声道，功率不如三极管的大，但是确实如楼主所说，一点也不热，只有C2073有大概40多度的温度，530基本是凉的，但是开到最大声音源不播放的时候，喇叭里有“次~次~次~”的声音，间隔大概1秒左右， ...

that sounds like some form of oscillation. first, make sure that it is not induced by the power supply - what is your amp's idle current? 2ndly, try a 220p capacitor between the collector and base of the phase splitter, and reduce it to the smallest that will cure the problem.

Please let us know how it goes. thanks.

hifiyeah

去掉输出电容 btl  有可能吗

millwood

原帖由 hifiyeah 于 2007-10-26 19:01 发表
去掉输出电容 btl  有可能吗

it does run on dual rail, without the output capacitor. But the DC operating point is not very stable, usually swings 100mv.

so you may want to put in a DC servo or good speaker protection.

Biglee_163

原帖由 millwood 于 2007-10-26 18:47 发表


that sounds like some form of oscillation. first, make sure that it is not induced by the power supply - what is your amp's idle current? 2ndly, try a 220p capacitor between the collector and ...

这看来是一些震荡的征兆.首先,请确认排除是由电源供应引起的--你的功放的静态电流是多少?
第2,尝试用一个220P的电容并联在分相器的基极和集电极之间(*分相器我认为应该是电路中的Q2,这个是我的理解,如有错误请指出 ),不断地减少这个电容一直到治愈你的问题.
希望等待你的结果,谢谢

Biglee_163

原帖由 millwood 于 2007-10-26 19:57 发表


it does run on dual rail, without the output capacitor. But the DC operating point is not very stable, usually swings 100mv.

so you may want to put in a DC servo or good speaker protection.

在没有输出电容的情况下这个电路可以双轨工作(应该就是指的BTL的意思吧 ).但是直流工作点不是很稳定,通常在100mv上下漂移.所以你或许要准备放一个直流伺服的电路或者配备一个好的扬声器保护电路

秋春弟

看这贴有上AUDIODIY的感觉 不同的是我感回帖了 在那没说过话

ateast99

感谢 millwood ,次~次~声消除了,是音源的问题

秋春弟

原帖由 ateast99 于 2007-10-27 12:12 发表
感谢 millwood ,次~次~声消除了,是音源的问题

LS的是按照millwood的图制作的还是1969M的图纸 声音和三极管的有什么区别?

millwood

原帖由 ateast99 于 2007-10-27 12:12 发表
感谢 millwood ,次~次~声消除了,是音源的问题

ateast99, I am happy that it worked out for you.

watch the idle current. it cannot be too small or it may cause too much RF interference from mosfet hard switching on / off.

I try to drop about 25mv on the RE resistors.

this is a great sounding amp. and I hope you like it.

also, experiment with it a little bit - that's where the simulators can be of great value.

millwood

原帖由 秋春弟 于 2007-10-28 02:18 发表

LS的是按照millwood的图制作的还是1969M的图纸 声音和三极管的有什么区别?

I will let others speak their perception of this amp. But you can check out Nelson Pass's impression of PLH (JLH1969 MOSFET shares the same phase splitter and output stage with the PLH), and others. But my view is below:

a) the JLH MOSFET has much better base and fuller sound ("bouncy" or vibrant or dynamic without being harsh). I can listen to it for hours with out getting tired. This is due to the mosfet's ability to handle large amount of current when needed.
b) the stability into reactive loads - translating into faster transients. the JLH, being a current feedback amp, is excellent for driving electrostatic. However, the BJT version starts to oscillate if you parallel a 2.2uf capacitor to the load. With the mosfet, the amp continues to sing while driving into a 2.2uf. Actually, when you start to connect the 2.2uf capacitor while the amp is powered on, you can see sparks flying out. Others have measured the slew rate to be in the 25v/us range, about 3x that of the BJT version.

秋春弟

millwood 考我英语了 呵呵还好基本明白  THANK U

秋春弟

IT IS PLH?