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发表于 2007-12-29 08:45
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原帖由 millwood 于 2007-12-28 19:09 发表
i wouldnt build it: the p3 or aksa are simpler and better amps in my view. even the ska.
having said that, you may try the following:
a) use a resister to replace r6/r7/vr1/z1/c8: it is way to complicated as is.
b) or use a constant current source for better psrr.
c) make r9=r5. or take out r9.
d) r4=r8=11 to 47. they are too large at 100ohm.
e) take out c13. the beauty of a bootstrap is that it becomes less capacitive and more resistive (thus less gain) at high freq. c13 killed that. taking out c13 allows better stability thus lower c14.
f) c14 too big to be a hi-fi amp. try to reduce it to < 47p. see the slew rate for your amp.
g) use a small resistor at the emitter of q3. 11-22ohm will do. it prevents q3 from going into hard saturation.
h) r15/18 in the wrong place. move them to the left.
i) use a small capacitor on q8. 0.1u will do.
j) add a small resistor in serial with vbe. see nap140.
k) r20/r21 are very good. aksa / john curl style.
l) i would add two 0r22 RE resistors to q6/q7.
m) use a choke on output. wound 10 turns on a 10ohm 5w resistor.
n) r12=r13.
m兄,你好。
a,用稳压管是为了方便适应更宽的供电电压
b,电流源我文中提到过,会使声音发硬,个人感觉加理解,不一定对,这一点值得大家讨论。
c,两个值不等可能可以平衡一下Q3的偏置,呵呵
d,100ohm这个电阻我倒没有试过变小,这个电阻是调节稳定性和开环增益的,有机会倒是要试一下你所说的小值情况呵呵。
e,C13这个问题,我改天再细听一下差别。暂时留下它的原因是我做电路的时候也习惯大电容并小电容,呵呵。你所说的我有机会验证一下。你的这个解释ms有些道理 ,但好像不大影响C14
f,C14小了会自激,这个是经我实测的,而且47p与100p也无所谓决定hifi与否,我记得在symasym里补偿相位的电容有用到330pF
g,射级电阻会影响音色,我在文中有详细说明,呵呵
h,这两个电阻没有问题的,呵呵。
i,这一点的确是好建议,回头就加上。有助于稳定电路!
j,这个电阻很关键?主要是我电路不太好加了
k,恩。这两个电阻现在许多功放都在用!
l,同g
m,恩。choke电路是应该加上的,不过建议直接加到喇叭后面。
n,R12与C12一起自举用,R13主要用作调节偏置,常见的电路中相等不一定意味着必须相等的
多谢好建议!呵呵
另外,强烈建议m兄试验一下这个电路,真的是简单好声!!! |
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