Peter Daniel said:Here is the latest schematic posted by other member. For more info check page23 of Aleph-X thread.http://www.diyaudio.com/forums/attachment.php?s=&postid=43959
Why does this version change the PS to 12V?
This is not a change, but the basic design.
Read the whole thread (I know, a lot of work
) and you will find that the design is scalable. If you increase the supply voltage you will get more output power, more power dissipation and you will need more fets to be paralleled. The 12V version is fine with just one output device per leg.
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Holger
Read the whole thread (I know, a lot of work

---
Holger
Thank you, Holger, for your response.
I did follow the thread but found a bit difficult
as I am new to this subject and from time to from maybe need some more elaboration. 😀 Thank people like you to bring the rest of us to a higher level
and appreciate poeple like you who do not just do
to the rest of us who are a little behind.
I still have the question on the rail voltage.
In Grey's original design there was one output device per leg either but 15V was used. If there are no other reasons, why not just keep the 15V in the latter version? 😕
I did follow the thread but found a bit difficult



I still have the question on the rail voltage.

mpeg7 said:why not just keep the 15V in the latter version? 😕
It's totaly up to you and transformer you choose.😉 I, for instance, go for 20V, because this is what my transformer and heatsinks allow me.
I've been reading this thread since day one. I've seen PCB layouts/artwork, but I haven't seen anyone offering to have these boards produced. Maybe I missed it? Is there any chance someone might have 50 boards made and sell them, a la BrianGT/Harvardian in another thread? Or a company, such as the Czech company that produces the blue boards for other Aleph designs, which might offer them?
dc said:I've been reading this thread since day one. I've seen PCB layouts/artwork, but I haven't seen anyone offering to have these boards produced. Maybe I missed it? Is there any chance someone might have 50 boards made and sell them, a la BrianGT/Harvardian in another thread? Or a company, such as the Czech company that produces the blue boards for other Aleph designs, which might offer them?
I second this. I sure would like a board already etched and drilled
for the components. My past experience with making my own
boards was an experience I don't want to repeat.
Regards,
Woody
Pehaps it is a little too early to set up a pcb production.
Not as long as we don't have the ultimate solution for the dc offset problem (okay, it isn't really one 🙄 ) without the power resistors at the output.
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Holger
Not as long as we don't have the ultimate solution for the dc offset problem (okay, it isn't really one 🙄 ) without the power resistors at the output.
---
Holger
A slight modification of an Aleph board will get you
an Aleph X, particularly if the output stage is a
separate board.
😎
an Aleph X, particularly if the output stage is a
separate board.
😎
Maybe this would be a good business idea? Modding Alephs into Aleph Xs?😉 You must have sell quite a few of them.

Slight Modification
The Aleph boards have only 1 set of circuitry for the current source setup and biasing the output fets. The Aleph-X requires that there be two for each half of the bridge.
Unless it can be done with what is on the board (an exercise for keener minds than mine).
Vinay
The Aleph boards have only 1 set of circuitry for the current source setup and biasing the output fets. The Aleph-X requires that there be two for each half of the bridge.
Unless it can be done with what is on the board (an exercise for keener minds than mine).
Vinay
I would imagine that with that kind of a mod, the whole front end board would have to be replaced.
I like the big round vu-meter for Bias indication...Would anybody know where to find that circular one and how it might be plugged into the amp?
XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200.........

XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200 XA 200.........

The bare meter costs a fortune from Selco, and it then
gets its own machined and anodized bezel, etc. You
don't want to go there.

gets its own machined and anodized bezel, etc. You
don't want to go there.

Yes Nelson,you are right,it is not the right thing to get for a DIY project...!
But I think about getting a backlightened Vu meter for bias indication,I find it cool on the face plate,and if you have a problem inside you see it from the faceplate...not with a nasty smell in the room or little bits of TO247 ejected at you!!!...If I am fast enough,I can reduce volume or running to switch of the amp...DIYaudio can be a sport,isn't it?
Regards
Anael 😉
But I think about getting a backlightened Vu meter for bias indication,I find it cool on the face plate,and if you have a problem inside you see it from the faceplate...not with a nasty smell in the room or little bits of TO247 ejected at you!!!...If I am fast enough,I can reduce volume or running to switch of the amp...DIYaudio can be a sport,isn't it?
Regards
Anael 😉
Only once have I been fast enough on the draw to
prevent a failure while watching runaway current.
This has potential as an Olympic event.

prevent a failure while watching runaway current.
This has potential as an Olympic event.

Well, you could design a high Impedance current sensing control circuit easily enough. Even use an off the shelf Honeywell circuit, connect the output to a relay that cut's power to the supply rails. You could even shunt the rails across a load resistor and disconnect the mains at the same time to eliminate any thump.
Oh how about redundant devices, if a transistor fails, current swing causes a similar circuit to flip the rail to the other device. When the failed FET stops conducting it trips a logic gate which turns on a LED telling you which device has failed.
or you could........
What were we talking about? 🙂
Anthony
Oh how about redundant devices, if a transistor fails, current swing causes a similar circuit to flip the rail to the other device. When the failed FET stops conducting it trips a logic gate which turns on a LED telling you which device has failed.
or you could........
What were we talking about? 🙂
Anthony
I have this rule of thumb:
When you hear a buzz and your woofer falls out onto
the floor, it is time to replace the transistor(s)
When you hear a buzz and your woofer falls out onto
the floor, it is time to replace the transistor(s)
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