Great, i appreciate your response. It makes sense now that you mentioned it.
Ok lets continue, she is a beauty!
Next step is the caps 8 x 10,000.
Ok lets continue, she is a beauty!
Next step is the caps 8 x 10,000.
I measured at the output of the power board: 50.0V on both rails.
I am assuming that is right on the mark?
Thanks again for encouraging me to continue.
I am assuming that is right on the mark?
Thanks again for encouraging me to continue.
Here are some photos. Making the kk-pcb boards fit the chassis required quite some work. Im enjoying the process and having fun when im not frustrated about how long it has taken.
Ok, my android tablet wont let my upload files.. to be continued.
Ok, my android tablet wont let my upload files.. to be continued.
audiosan: small question: in you aleph 2, why do you create so many ground loops on your caps? isn't it better to just interconnect the first 2 and NOT the rest? to make a star ground? the ground loops can induce noise in your circuit...
no no no no. connect ALL.
thats right on the spot. you will see 45-46V when the amp is conected.I measured at the output of the power board: 50.0V on both rails.
I am assuming that is right on the mark?
Thanks again for encouraging me to continue.
its looking good🙂
karajak - when you say it's not working, what are you measuring or referring to? Is it lack of sound at the speakers? Or something else?
i checked everything thorougly.the only trouble i found is rails voltage.
-54+54i think is high.
looks like all the wires are right. you did a nice job.
if its not drawing any current the rails will be high.
i cant see the color codes of the resistors, maybe double check them.
what kinda voltage drop do you have on the MPSA18's?
you might want to check your 56.2k and other res around that mpsa18...
This is a monobloc construction.The other channel i checked first fried the irfp240s.Checking everything again and again i checked this channel using light bulbs indicating false .
I powered up one channel today, and it blew the main fuse...
My power pcb seems to work well and i can run it without the amp board connected. when i connected the amp board the led on the amp board didnt light up at all and the main 110v fuse blew. The fuse may be too light, it is an 110v. 3 amp fast blow fuse. Should i try a heavier fuse or are the some things i should measure/check first?
My power pcb seems to work well and i can run it without the amp board connected. when i connected the amp board the led on the amp board didnt light up at all and the main 110v fuse blew. The fuse may be too light, it is an 110v. 3 amp fast blow fuse. Should i try a heavier fuse or are the some things i should measure/check first?
Thanks Audiosan. I will put a slow blow fuse in... i wanted to protect myself first and foremost...
Thanks again.
Thanks again.
Ok, i got brave and put a 5A slowblow in.....
I also plugged the amp into a kill-a-watt device to see how many amps it was pulling in.
Well, the fuse didnt blow for about a minute, thats when i turned off the switch, i was worried because i started to smell something... remember this is my first build and my first class A.
Upon inspection i found several components that were very hot..
The matched IRF9610`s, especially the one close to the speaker output.
Also the big resistors on the boards by the IRF240`s
Also the current inrush limiter was hot hot hot, which i read is normal.
I`m a bit scared and im not sure if this is normal or not.
The amp drew 6.2 amps and slowly climbed to 6.5, does that seem right?
Are there any measurements i can take to verify proper operation?
This is very exciting and scary at the same time, what a thrill!!!
😱 😀. 😕
😀. 😀
I also plugged the amp into a kill-a-watt device to see how many amps it was pulling in.
Well, the fuse didnt blow for about a minute, thats when i turned off the switch, i was worried because i started to smell something... remember this is my first build and my first class A.
Upon inspection i found several components that were very hot..
The matched IRF9610`s, especially the one close to the speaker output.
Also the big resistors on the boards by the IRF240`s
Also the current inrush limiter was hot hot hot, which i read is normal.
I`m a bit scared and im not sure if this is normal or not.
The amp drew 6.2 amps and slowly climbed to 6.5, does that seem right?
Are there any measurements i can take to verify proper operation?
This is very exciting and scary at the same time, what a thrill!!!
😱 😀. 😕

Measure the rail voltage, measure the DC offset (the DC voltage on the speaker outputs.)
How hot are the components you mentioned? Can you keep your fingers on them?
And the thermistors do run really hot in normal operation. Like burn yourself hot. Don't touch them.
How hot are the components you mentioned? Can you keep your fingers on them?
And the thermistors do run really hot in normal operation. Like burn yourself hot. Don't touch them.
Last edited:
This is very exciting and scary at the same time, what a thrill!!!
Oh no your hooked. Like a drug.
One of the 9610s is a constant current 4 the other 2 so it will be warmer.
What wattage are the resistors?
Mesure the voltage drop over the source resistors next time.
Oh no your hooked. Like a drug.
One of the 9610s is a constant current 4 the other 2 so it will be warmer.
What wattage are the resistors?
Mesure the voltage drop over the source resistors next time.
- Status
- Not open for further replies.
- Home
- Amplifiers
- Pass Labs
- My Dream Aleph 2 Coming True