I have a DIY aleph J. It works just fine and is quiet. What worries me a little is that I get a movement in the speaker element when I turn off the amplifier. No bang, just movement.
What can this be and is there any problem. Mint speakers are 92-93db
What can this be and is there any problem. Mint speakers are 92-93db
I wouldn't worry if movement is without a bang and even 5mm of excursion
example - some of amps having none bang or movement with "normal" speakers gave me some scare when I tried them on my ancient RCA 15" ..... even if 16R, they popped even more than 5mm
go figure
some numbers - I'm ignoring even 2V of initial pop, if change is not abrupt ( no energetic bang, as you say)
example - some of amps having none bang or movement with "normal" speakers gave me some scare when I tried them on my ancient RCA 15" ..... even if 16R, they popped even more than 5mm
go figure
some numbers - I'm ignoring even 2V of initial pop, if change is not abrupt ( no energetic bang, as you say)
It is a single 24V supply. But audio swings both ways. The trick here is to set the amplifier output to half-supply DC, and block the DC with a capacitor.
At turn-on the output before the cap must rise to 12V, and at turn-off it must decay to zero.
Apparently this amp comes-up much slower than it decays down. Which makes sense. The power can come up but a bias network slow the rise. But when power goes-away it must fall down. Slowed only by storage of the main filter caps.
I remember when "ALL" audio transistor amps did this. Change of voltage slowed just enough to not make frightening noises. While fashion changed to bipolar designs (with different troubles), Mr Pass defies fashion when he wants; and he knows how to do it good.
At turn-on the output before the cap must rise to 12V, and at turn-off it must decay to zero.
Apparently this amp comes-up much slower than it decays down. Which makes sense. The power can come up but a bias network slow the rise. But when power goes-away it must fall down. Slowed only by storage of the main filter caps.
I remember when "ALL" audio transistor amps did this. Change of voltage slowed just enough to not make frightening noises. While fashion changed to bipolar designs (with different troubles), Mr Pass defies fashion when he wants; and he knows how to do it good.
It's most likely due to mismatches in the time constant on the constant current sources at the front end and output stage, both of these will affect dc offset at turn on and turn off.
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Seems like it's normal with Alpeh j, right?
Thought maybe there was something wrong with the mounting of my amplifier.
Thought maybe there was something wrong with the mounting of my amplifier.
Turn-on/turn-off thumps are not really anything to worry about provided they don't push the voice coil beyond xmax of speaker
