My Aleph J sounds wonderful for the most part, but I have a couple of problems that I would like to address.
First one: with no input or output connected and the amp powered on everything looks normal meaning all the Leds are lit as they should be. When I power off the amp the PS Leds take about 1 minute to go completely out. However, with the speakers connected and I power off one side immediately goes dim while the other side is normal.
What could this be?
Second problem: if I reverse the input connections, I get no output from either channel, but the other way works perfectly. I have no idea what to look for to solve this issue.
any advice would be greatly appreciated!!
First one: with no input or output connected and the amp powered on everything looks normal meaning all the Leds are lit as they should be. When I power off the amp the PS Leds take about 1 minute to go completely out. However, with the speakers connected and I power off one side immediately goes dim while the other side is normal.
What could this be?
Second problem: if I reverse the input connections, I get no output from either channel, but the other way works perfectly. I have no idea what to look for to solve this issue.
any advice would be greatly appreciated!!
1)Yes, the rails discharge at very different rates, that is normal.
2) I don’t follow what is happening.
2) I don’t follow what is happening.
For 2), are you saying that you have sound when you have preamp_left_output to Aleph_left_input and preamp_right_output to Aleph_right_input,
but no sound when you have preamp_left_output to Aleph_right_input and preamp_right_output to Aleph_left_input?
but no sound when you have preamp_left_output to Aleph_right_input and preamp_right_output to Aleph_left_input?
I know the rails discharge at different rates but what puzzled me was the difference between amp connected and amp disconnected ?
@Dennis Hui yes that is exactly what I'm saying 🙂
I'll get some pics as soon as I can...
@Dennis Hui yes that is exactly what I'm saying 🙂
I'll get some pics as soon as I can...
Check for any DC offset in the channel that has the LED's dim immediately when speakers are connected.
If you mean swapping L and R around then it makes no sense to me either. Hazy thinking... make sure both inputs are correct for polarity and you haven't got one inverted. It would only make sense with oddball grounding... however 🙂
OK, so I traced the output problem to a bad rca connector on the amp. Problem rectified.
However as for the discharge rates of the rails, Left side takes about 20 seconds and the right side takes about 3 minutes.
That difference seems a little extreme to me ?
However as for the discharge rates of the rails, Left side takes about 20 seconds and the right side takes about 3 minutes.
That difference seems a little extreme to me ?
@rtate To clarify, are you talking about the V+ and V- rails discharging at different rates, or one channel playing for a long time and the other turning off very quickly...?
Rails discharging unequally at power off with a load attached is 100% standard behavior for an Aleph.
Rails discharging unequally at power off with a load attached is 100% standard behavior for an Aleph.
well, these are really "some"
few, to see general arrangement of things inside, then as many you can, with details
how LEDs on channel pcbs are behaving
do you have different power-on and power-off behavior of channels, regarding plop/cone movement in speakers
are LEDs in PSU are same type, are equal series resistors?
few, to see general arrangement of things inside, then as many you can, with details
how LEDs on channel pcbs are behaving
do you have different power-on and power-off behavior of channels, regarding plop/cone movement in speakers
are LEDs in PSU are same type, are equal series resistors?
The LED's on the pcb behave the same. i.e.. they take a couple of minutes to fully discharge.
Music stops quickly on the channel in question.
LED's are the same part number and bleed resistors were measured before installation
Music stops quickly on the channel in question.
LED's are the same part number and bleed resistors were measured before installation
if you can't find any visual difference between PSU pcbs and also between channel pcbs, there is no other way than trying to determine where is origin of different behavior
disconnect PSU pcbs from channel pcbs, load each rail on both pcbs with appropriate loadng resistor
say 100mA for start, then decide do you need more
if rail is nominally 24Vdc, so that's 240R, dissipation being P=I^2*R
220R is standard, thus I= 24/220=110mA, heat 2W6, calling for 7-10W resistors
if in doubt, go to higher load (less ohms)
other way is - swap PSU lines to channel pcbs; if problem stays with particular PSU side, it's PSU
disconnect PSU pcbs from channel pcbs, load each rail on both pcbs with appropriate loadng resistor
say 100mA for start, then decide do you need more
if rail is nominally 24Vdc, so that's 240R, dissipation being P=I^2*R
220R is standard, thus I= 24/220=110mA, heat 2W6, calling for 7-10W resistors
if in doubt, go to higher load (less ohms)
other way is - swap PSU lines to channel pcbs; if problem stays with particular PSU side, it's PSU
We need a bird's eye view of the interior of the amp showing everything (including power supplies and transformers) and wiring to the amp PCBs?
So far I only make out a single transformer, and this photo: https://www.diyaudio.com/community/attachments/img_2640-jpg.1232581/ seems to show wiring going out to two channels from a single power supply board.
So far I only make out a single transformer, and this photo: https://www.diyaudio.com/community/attachments/img_2640-jpg.1232581/ seems to show wiring going out to two channels from a single power supply board.