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Old 27th March 2004, 01:01 PM   #1
Jena is offline Jena  England
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Join Date: Mar 2004
Location: London
Default Decision Decision


First of all thanks for your suggestions in Aleph amp.
I've just build my first Aleph 4 amp, it taked 2 years, followed the instructions written in the own manuals by Nelson Pass, and after I've spent more mounth in some great Audio website my idea is changed a little bit.
About your article there is few opinion in terms of fine tunnig, let me show you some measurements and pls give me your opinions.
In my Aleph 4 I've :
+ 40 Vcc = 2 A circa
- 40 Vcc = 2 A circa
In Idle mode I've 5 mV of Ripple
On each resistors sharing I've measured 560mV up to 600mV circa, for each channel.
On the MosFet that give + 4Vcc to the couple of input MosFet I've measured + 3.76 Vcc, is better or not. Mybe the problem is that I've choose IRFP9620 instead of 9610?
There is a lot of opinion in terms of matching devices, some say to measure the VGS for 1 minutes and others for 5 minutes, you know that the VGS change and is not stable in the time, pls let me know.
Otherwise when my friends heard the sound they remained astonished.
You know if there is some improvement about the fine tunning.
Now I've decided to built an Aleph 1.2 and also a X version, but in the X version the frontend in biased in class AB version, and in DIYaudio forum there is a different opinion between this two amplifier, X version not work in a pure class A operation.

I know that I've did lot of question but before to start in a new mission I need to get more clear my ideas.

thanks a lot for your answer...

:xeye: :xeye: :mad: :clown:
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Old 27th March 2004, 09:07 PM   #2
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I hope that ripple figure is the power supply, not the output
of the amp.
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