I have almost all the parts except Q2 (small signal pnp bjt) and the mosfets, IRFP240 Q5-Q8. Can anyone suggest a source for these?
ztx450 and bc560c are the part numbers for Q2
ztx450 and bc560c are the part numbers for Q2
can't see from your profile where you are located, so I can't name a source nearest/easiest to deal with
For matched IRFP240, you can try Randy here: https://www.diyaudio.com/community/...fets-and-irfp240-mosfets.365386/#post-7040018
mosfets - as Dennis said - from someone here selling matched ones
bjt - no matching, buy them in nearest grocery store
or mouser
or digikey
bjt - no matching, buy them in nearest grocery store
or mouser
or digikey
Probably just a typo but q2 is a pnp transistor so ztx450 is not suitable. You were probably thinking of ztx550.
Would someone give me a little more insight on how to pick an appropriate alternative for that PNP? I see the part listed from extreme_boky, but I’m not sure why the specs for that and the originals on the bom are a good match.
Simple, high level would be much appreciated. I found a nice explanation on how to pick a PNP, but I’m not yet capable of finding the necessary values from the schematic.
Simple, high level would be much appreciated. I found a nice explanation on how to pick a PNP, but I’m not yet capable of finding the necessary values from the schematic.
Pretty much any PNP transistor will do. This particular one does not reside in the signal path - it works with a Zenner diode to set the current through the input differential pair.
Any PNP transistor will do... but the transistor orientation AND the leg/pinout need to be carefully checked/considered. I provided a solution that doesn't require a leg swap, i.e. the replacement is a like-for-like drop-in replacement... to ensure a minimum hassle and guaranteed success.
Other PNP small signal transistors can also be used... but pay attention to the pinout/orientation of the transistor as a whole... it can get quite confusing.
Here you go... if you feel adventurous, you could try the BC560...
Any PNP transistor will do... but the transistor orientation AND the leg/pinout need to be carefully checked/considered. I provided a solution that doesn't require a leg swap, i.e. the replacement is a like-for-like drop-in replacement... to ensure a minimum hassle and guaranteed success.
Other PNP small signal transistors can also be used... but pay attention to the pinout/orientation of the transistor as a whole... it can get quite confusing.
Here you go... if you feel adventurous, you could try the BC560...
Hello ,
My aleph J one Chanel is fine and sound good but other one got problem with DC offset .
Dc off set is canot trim and no sound .
Pls can you tell which parts are problem ?
Best
My aleph J one Chanel is fine and sound good but other one got problem with DC offset .
Dc off set is canot trim and no sound .
Pls can you tell which parts are problem ?
Best
Mulburg, the pinouts Extreme_Boky gave you are good references.
Note that in the store's Aleph-J board, the small transistors (for example, Q2) were laid out with a generic 3-pin footprint with the pin holes labelled (see attached), as opposed to an TO92 footprint (with flat one side and round on the other). As as long as you have a CBE or EBC part, you just match up the pinout of your part to the labels and you'll be fine.
Note that in the store's Aleph-J board, the small transistors (for example, Q2) were laid out with a generic 3-pin footprint with the pin holes labelled (see attached), as opposed to an TO92 footprint (with flat one side and round on the other). As as long as you have a CBE or EBC part, you just match up the pinout of your part to the labels and you'll be fine.
Finishing an AJ build. Plugged it in through a dim bulb tester. Light dimmed some but didn't go out. I don't know whether that is good or bad at this stage. I completed the power supply side of things months ago. It checked out fine so I'm thinking it's in the amp boards/wiring. Not sure I have a problem or not. The LED 2s on both channels light up brightly and stay on for awhile after power off. LED 3s start bright and dim after a few seconds. I'm over my head at this point. Does this sound like things are OK? It was a little sketchy finding info on wiring betwee the Power supplty pcbs and the amp pcbs. I ran wires from the V+ and V- on the power supply to V+ and V- on the amp boards. The grounds go from one of the many ground lugs on the psu to what I think is a ground on the amp board. It's the pink wires in the pics. I've included some pics hoping they might be helpful. Ideas very welcome! Or maybe everything is great and I'm worrying about nothing!!?
Uh oh. I think I found a problem in my build. I may have put all the mosfets in backward. I put them in with the metal side out (away from the heat sink). Do they go the other way? If so, is there a chance I damaged something?
Oops. Yes, they definitely go the other way. Seeing that in your picture.
Depending on how far you got into the process, yes - they could be damaged. You had a DBT in place, which is good.
Re-bending the legs back around may be a bit troublesome, but you could check the parts.
Depending on your level of comfort, your ability and knowledge to test the components once removed, and your desire to potentially re-solder those components a number of times... I'd lean toward their replacement.
That's just one person's opinion. I'd wait for a few more thoughts.
Depending on how far you got into the process, yes - they could be damaged. You had a DBT in place, which is good.
Re-bending the legs back around may be a bit troublesome, but you could check the parts.
Depending on your level of comfort, your ability and knowledge to test the components once removed, and your desire to potentially re-solder those components a number of times... I'd lean toward their replacement.
That's just one person's opinion. I'd wait for a few more thoughts.