The Aleph Design Reloaded

Official Court Jester
Joined 2003
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sorry, I didn't understood in first moment your post ...... by habit , I was fixated on AC gain issue, usually taken care of with modulating resistor from output node

frankly, I never investigated effect of varied colector resistor there ...... always used lower value ( 1K5), presuming that more mA flowing there can only be good thing etc.
 
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Joined 2009
Paid Member
Inspired by the comments here I made the zillionst Spice of A3 and I got the H2 neg phase in Spice only by canceling two of the Aleph 0R47 at the output. With four parts I get always pos phase H2.
Nelson assured me many times that the original had neg phase H2.
So my question could there be an interdependence to the transconductance difference between the IRF240 in the original amp and the IRFP240 used in our rebuilds? The IRFP seems to have mostly a portion more transconductance.
 

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好了,开始吧。

上个月我从后面的架子上收集了一些“垃圾”
存储空间(你记得的那个
为了挽救为TO-3设备钻探的散热片
另一个项目(另一个索尼SIT放大器)。

打开它们,我发现它们的状态很好
值得稍微清洗和修理一下。

您可能还记得我之前发布了对Aleph 3的更新
它在输入阶段合并了东芝2SJ109 Jfet,而这
仍然是一个有价值的更新有两个问题;第一,它很难
得到这些部件,其次,它们只适用于低电压放大器
这就忽略了其他的阿莱佛。

然而,在这些我决定尝试我最喜欢的小功率Mosfet
东芝2SJ 313。除了不同的包装和引脚
放大器模型,他们将下降的权利作为替代品,他们需要
匹配Vgs在10毫安。

东芝的是首选,但你也可以凑合着用其他同类的
如果你不能得到这些零件。

注意到一些单位有齐纳噪音与r105在4.7 k,我放弃了
值设置为3.3 k,您将注意到我可以选择删除q104,超出-
电流保护。另外,我直接移动了底盘接地连接
到AC大地。

东芝Mosfet的加入立即带来了改进
在电源噪声抑制中,通常将其降低4到6倍
低至50 uV不加权输出。仅这一点就证明了努力是合理的。

此外,作为一个调整,你可以取代220 uF帽与丝绸帽从爱尔纳。

听力测试显示比原来的有了显著的提高,我
圣诞节时把这些给了我的生意伙伴。

:cool:

1nF在Aleph中,每个通道一个或两个电容器来抑制可能的接触
Thank you for your reply, but through the experiment, it is found that if you remove this 1nf bass, it will get worse, plus there will be enough bass. My friend told me that this is a feedback capacitor, not for stabilizing the circuit.
IMG_20220731_155823.jpg
 
谢谢你的回复,但是通过实验,发现如果去掉这个1 nf的低音,就会变差,再加上会有足够的低音。我的朋友告诉我,这是一个反馈电容,不是用来稳定电路的。 View attachment 1076605

谢谢你的回复,但是通过实验,发现如果去掉这个1 nf的低音,就会变差,再加上会有足够的低音。我的朋友告诉我,这是一个反馈电容,不是用来稳定电路的。 View attachment 1076605
1nF在Aleph中,每个通道一个或两个电容器来抑制可能的接触
In Pass A5, this capacitor is 681pf, not 1nf
 
Hi guys! I would like to share this version of A3 with you.
It is the result of some information taken around by the various forums also by Aleph J from which I took the slightly different part of the bias from the A3.
Furthermore, this version also includes the balanced input, still in the Irf9610 version because the 2sj74 is much more expensive and difficult to find original.
I have provided several settings to be able to adjust:
1) LTP BIAS
2) DC OFFSET
3) BIAS
4) AC GAIN
I'd like to know your opinions/advice before having to make the pcb.
Thanks in advance to all of you and to Mr. Nelson Pass for his generosity.
 

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