Build a pair of aca. Sounds magnificient. I do have a one problem; power off pop noise. Any idea how to prevent this? Or what causes this?
Thanks!
Thanks!
Tried with Celestion 332, 87db apprx. There is a loud pop. Also have 98dB full rangers, I cannot imagine how loud it may pop.
Also measured dc offset at the outputs. First turn on, dc around 0,7V! It's decreased to ~10mV in 10-15 seconds.. Is this normal for ACA?
Yes, all caps polarity is correct. Double checked before power on. All caps bought from Digikey. It sounds ok, after 10-15 sec dc offset goes down to 10mV. But power on dc offset bugs me, don't want to ruin my lovely celestion 332s.
One thing; I didn't mount&solder any led yet.
I don't think the led being left off should be a problem. Just wondering, was the offset measured with speaker connected, or with no load?
I'm getting a 3 volt pulse about 50 mSec wide. I put some capacitance on
the power supply (currently it has none) and that takes it down. 10,000 uF
@ 25V gets about 1.5V at 100 mSec, and the power supplies that are used
have no difficulty charging that cap on turn-on.
That would be the simple solution, a more complex one being gradual
shutdown of the circuit.
😎
the power supply (currently it has none) and that takes it down. 10,000 uF
@ 25V gets about 1.5V at 100 mSec, and the power supplies that are used
have no difficulty charging that cap on turn-on.
That would be the simple solution, a more complex one being gradual
shutdown of the circuit.
😎
Mr.Pass, am I understood correctly, you're suggesting adding capacitance between power supply & ACA?
I assume you are using the computer brick power supplies. Try an experiment. Unplug the PS from the wall and see if the thump is minimal. If it is, then maybe you can use something like the switch on a power strip to meet your needs. The PS's would be plugged into that strip. Either way, I do like Mr. Pass's idea of putting in a cap after the PS and that would be a good idea anyway.
It takes a lot of capacitance to really get the thump down. At some value,
the switcher will sense a short on turn-on, and it won't start.
Like I said, there's more complicated solutions, but I'm not sure how many
drivers are going to object to the current state of affairs. The ACA can deliver
that level of signal to the bottom end with music.
😎
the switcher will sense a short on turn-on, and it won't start.
Like I said, there's more complicated solutions, but I'm not sure how many
drivers are going to object to the current state of affairs. The ACA can deliver
that level of signal to the bottom end with music.
😎
sorry for being naive but where does the cap go, between the + and - leads from the power supply, inside the chassis?
