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Thanks Eric. I am using Open office so things are a litle different, i missed the tabs.
I think I will stick with Kari's onboard part list. It is generally the same .... I am concerned about a lack of diodes around the power input. There seems to only be oine diode on the board.
This projest is obviously more of a task than the Aleph 5s I ve just built. But Hopefully all will be ok. My concer at the moment is that I hope my fet matching is up to scratch. I matched the diff pair to 0.01vgs..... hope this is enough.
The next would be the tuning up at startup. I havent measured the dc offset etc on my aleph 5s so I guess I could start there....
I will have top read up on that... I dont have a scope though, not even sure if I need it for that......
best get reading....
thanks again everyone for your advise... Im sure I will be back very soon.
dave
I think I will stick with Kari's onboard part list. It is generally the same .... I am concerned about a lack of diodes around the power input. There seems to only be oine diode on the board.
This projest is obviously more of a task than the Aleph 5s I ve just built. But Hopefully all will be ok. My concer at the moment is that I hope my fet matching is up to scratch. I matched the diff pair to 0.01vgs..... hope this is enough.
The next would be the tuning up at startup. I havent measured the dc offset etc on my aleph 5s so I guess I could start there....
I will have top read up on that... I dont have a scope though, not even sure if I need it for that......
best get reading....
thanks again everyone for your advise... Im sure I will be back very soon.
dave
dhole
http://web.vip.hr/pcb-design.vip/alephx.html
Yes your right mate should be 0.39R 3W(rs no. 294-2855) not 39R(rs no.152-381), using the schematic below from
http://web.vip.hr/pcb-design.vip/alephx.html
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I'm using Vishay/Dale 1% 1/4w metal film resistors from Mouser for all of my Aleph-Xs that are currently in progress. I ordered a number of each value and am carefully matching values across each side of the amp. There is a surpirsing amount of variability in the measured valued, so it is clearly a worth while effort.
For the a40 amp that I build a few years ago, I exclusively used Shinkoh Tantalum 1% 1/2w resistors and they all measured exactly spot on values - but they cost nearly $5 each (the Vishay/Dales are only $0.20 each).
For the a40 amp that I build a few years ago, I exclusively used Shinkoh Tantalum 1% 1/2w resistors and they all measured exactly spot on values - but they cost nearly $5 each (the Vishay/Dales are only $0.20 each).
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I don't recall reading anything that he posted about matching resistors. The Aleph-X that has developed here seems to be very sensitive to component selection - if things are not matched carefully, DC offset is a likely outcome. I have carefully matched resistors and mosfets on each side of the amp. Don't know the result yet, haven't built my power supply.
Nelson probably has a more elegant solution...
Nelson probably has a more elegant solution...
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dhole said:
Is there anybody who has actually finished the aleph-x using kari's boards?
From what I can see, there seems to be an error on the PCB:
The T3 (the irf 9610 supplying the differential pair) looks to be inserted the wrong way around.
Anyone else found any other errors on kari's main boards? (or can confirm what i've seen).
I'm not an electronic engineer, so I may very easily be mistaken.
Regards,
Jacco
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