So I don't have to obsess with matching and thermal coupling etc.
It makes the whole process easier of choosing matched parts for the J2-like input differential pair (4 mosfets - 2 in parallel on each side of differential)
It's not really such a big deal, it's just a nice thing to have when you parallel parts.
It makes the whole process easier of choosing matched parts for the J2-like input differential pair (4 mosfets - 2 in parallel on each side of differential)
It's not really such a big deal, it's just a nice thing to have when you parallel parts.
That was some years ago (3-4?) so I'll need to dig out my notes and let you know. I did test the FQP30P which was (if memory serves me) also quite decent.
Lt you know if I find details. Cheers.
Hell every one. After lots off searching, reading pass topics i dont find answer for my questions, and problem. My friend have pass aleph 3 clone on chinese pcb. It plays good. But problem is when he connect his new diy speakers with real 100db eff. Problem is with noise on high frequency speaker, it is noisy and when music have quaiter parts i can hear this noise in listening place. I have atached photo with this aleph schematic, it quite the same, but have irfp250n and pcf28. Runns on symetrical 22v with very good power supply. Can any body help me with the noise? I have heard that some diyers change irf9610 for jfets, but they say that magicnin music is not that same. And lost one, I dont know why i have irfp250n not like rest of alephs irfp244. Mayby 244 sound better? Very thanks for help.
Hell bmxmen,
I would either think of a problem with the crossover of the tweeter in the diy speaker or a layout problem of the pcb.
In the first case, you better ask in a loudspeaker forum. In the latter case, you better contact the creator of the pcb and ask him about problems known about that pcb.
I don't find anything about a pcf28 transistor. Maybe you replace those? And of course, an aleph 3 was not designed for irfp250. You better look for 8 matched original irfp244 and replace them.
I would either think of a problem with the crossover of the tweeter in the diy speaker or a layout problem of the pcb.
In the first case, you better ask in a loudspeaker forum. In the latter case, you better contact the creator of the pcb and ask him about problems known about that pcb.
I don't find anything about a pcf28 transistor. Maybe you replace those? And of course, an aleph 3 was not designed for irfp250. You better look for 8 matched original irfp244 and replace them.
No no,crossover is perfect. Problem is in the noise from my pass 3 not in loudspeakers they have 100db eff so amplituner must be quiet. Mr Nelson have add some upgrades , jfets on in, some resistors . Mayby i will try to change resistors at first? Mayby try to change 220r on irfp to 50ohms? someine have done this change.
So i have change 2sa1845 on mpsa18 . Add 470nf on 220uf near mpsa18. And 1nf on
Base and colector from mpsa18
Base and colector from mpsa18
Pass DIY Addict
Joined 2000
Paid Member
From the images that you've posted, it looks like you need to do some cleanup on your PCB after soldering. Get rid of the flux and the splattered solder droplets. Also, it would be helpful if we could see detailed images of the entire wiring of your amp in a single image. You've shown us parts, but we can't see the overall layout of parts, wires, placement within the chassis, etc.
Very thanks, on days i will do that. Did any body have connected pass 3 to laudspekers that have more that 97db eff?
I ran a proper factory Aleph 3 on 100+dB eXemplar/Altec horns for years. It was quiet. I am running Aleph 30 clone monoblocks on 94dB JBL monitors now - they are quiet, too.
Experience with Aleph clones is they need careful attention to wiring, wire routing, twisting wires, etc. to keep them quiet.
See this link:
https://hifisonix.com/ground-loops/
I dont have problem with humm 50 or 100hz but on noise on twweeter sumethink much upper. Please tell me my friends , mayby it is problem with my irfp250? And i must change for irfp244 ?
Hello 10uf cap works very well. Noise is 30%quiter. Please tell me chow big cap can i use
? and this cap is cutting audiable freq?
? and this cap is cutting audiable freq?
If bypass cap helped I would next try to increase current through Z5 by dropping R108 from 4.75k to around 3k. With 22V rail you only have 2.75mA through there with 4.75k ohms.
