A501 Luxkit DC POWER AMPLIFIER
Any chance obtaining a download of the manuals for this unit.
I have a A501 which is working, except when run in the class A mode the idle temperature climbs to 140 degreesF within 1 minute and continues to rise. This seems excessive, I can feel the liquid boiling in the heat transfer tube at idle. I expect heat as with class A 70% power draw at idle but.....?
I'm wondering if just idle current adjustment is required, and it's falling into a thermal runaway scenario.....?
DC Balance always reads 0v across outputs and is stable, at minimum the correct adjustment procedure for the DC-Balance and the A-I (idle current) would be most appreciated. Also if possible the AB-I (idle current) adjustment could be checked and verified against what info you might have in the manual.
Any chance obtaining a download of the manuals for this unit.
I have a A501 which is working, except when run in the class A mode the idle temperature climbs to 140 degreesF within 1 minute and continues to rise. This seems excessive, I can feel the liquid boiling in the heat transfer tube at idle. I expect heat as with class A 70% power draw at idle but.....?
I'm wondering if just idle current adjustment is required, and it's falling into a thermal runaway scenario.....?
DC Balance always reads 0v across outputs and is stable, at minimum the correct adjustment procedure for the DC-Balance and the A-I (idle current) would be most appreciated. Also if possible the AB-I (idle current) adjustment could be checked and verified against what info you might have in the manual.
I have the service manual for the Z501.
You can download from http://https://www.hifiengine.com/manual_library/avance/z501.shtml
Or you can email me if you prefer? File is 7.3Mb
You can download from http://https://www.hifiengine.com/manual_library/avance/z501.shtml
Or you can email me if you prefer? File is 7.3Mb
Hi Don,
looks like DruidA posted a good link for you.
I have built two A501's (z501) and both will boil after switching to the A mode. It changes the output transistor bias. They never turn to the off as they are biased in a positive state.
The boiling sound is normal and at very low volume levels maybe a little annoying.
As to the actual temp they run at, I am not sure. Hot they run! I can measure it if you like and post it for you.
I would just verify your Offset and bias settings in both modes. If they cannot be obtained you have another issue.
let me know how you make out.
Jb
looks like DruidA posted a good link for you.
I have built two A501's (z501) and both will boil after switching to the A mode. It changes the output transistor bias. They never turn to the off as they are biased in a positive state.
The boiling sound is normal and at very low volume levels maybe a little annoying.
As to the actual temp they run at, I am not sure. Hot they run! I can measure it if you like and post it for you.
I would just verify your Offset and bias settings in both modes. If they cannot be obtained you have another issue.
let me know how you make out.
Jb
As zlrig has said, check the bias and offset, mine doesn't run that hot.
Saying that, I realise that I have never checked my bias settings, only offset!
Saying that, I realise that I have never checked my bias settings, only offset!
I also have quite a bit of info on the Z504 power amp if anyone needs it!
This is my everyday amp
This is my everyday amp
LUXKIT Z501 - Protection Circuitry Problems!
Guys
My LUXKIT Z501 is a gorgeous sounding amp that gave my FIRST WATT J2 a run for its money - the Z501 is that good.
However, last time that I fired it up, it seems like the protection circuitry just locked me out. Instead of the operation LED turning green for go, it just stayed red - winking off and on, if I recall correctly.
It seems to me that it's probably just a failed component somewhere, as this is a very old amp.
I have a the schematic that is posted earlier in this thread, which I believe to be correct, but I don't know where to start to find the Protection Circuitry components.
Is anyone able to shed some light on this for me? Appreciated.
Guys
My LUXKIT Z501 is a gorgeous sounding amp that gave my FIRST WATT J2 a run for its money - the Z501 is that good.
However, last time that I fired it up, it seems like the protection circuitry just locked me out. Instead of the operation LED turning green for go, it just stayed red - winking off and on, if I recall correctly.
It seems to me that it's probably just a failed component somewhere, as this is a very old amp.
I have a the schematic that is posted earlier in this thread, which I believe to be correct, but I don't know where to start to find the Protection Circuitry components.
Is anyone able to shed some light on this for me? Appreciated.
LUMAN Luxkit Z501 Manual & Schematic...
Have attached the manual which includes the proper Z501 Schematic towards the end...
Have attached the manual which includes the proper Z501 Schematic towards the end...
LUXMAN Luxkit Z501 Manual & Schematic...
Let's try that again...
Have attached the Z501 Schematic...
Let's try that again...
Have attached the Z501 Schematic...
It could be that the protection circuit is doing its job and there is a fault somewhere?
Unless everything settles properly, the output relays will not click in, so check for dc on the inputs (points P1 & P2) to those as a first measure.
Unless everything settles properly, the output relays will not click in, so check for dc on the inputs (points P1 & P2) to those as a first measure.
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Why DC at the output???
Thanks DRUIDAUDIO.
Seems like the protection circuitry is just doing its job then, which the manual states is: "...when a DC voltage exceeding approximately + or - 2.5V is detected at the speaker terminal."
So I guess I need to find out why?
Even with our (normally fully operational) speakers unplugged, the Protection Circuitry disables operation. This rules out any problem emanating from the speakers, I guess.
I have looked over the amp very closely, looking for burnt components, stray wires, poor connections, etc. and everything seems perfectly intact.
Previously, this amp has performed flawlessly, so that gives me some hope of resolution.
QUESTION: Where should I start, to find the source of this unhelpful DC voltage?
Thanks for helping me with this. Internal photos provided, in the event that someone spots something obvious.
Thanks DRUIDAUDIO.
Seems like the protection circuitry is just doing its job then, which the manual states is: "...when a DC voltage exceeding approximately + or - 2.5V is detected at the speaker terminal."
So I guess I need to find out why?
Even with our (normally fully operational) speakers unplugged, the Protection Circuitry disables operation. This rules out any problem emanating from the speakers, I guess.
I have looked over the amp very closely, looking for burnt components, stray wires, poor connections, etc. and everything seems perfectly intact.
Previously, this amp has performed flawlessly, so that gives me some hope of resolution.
QUESTION: Where should I start, to find the source of this unhelpful DC voltage?
Thanks for helping me with this. Internal photos provided, in the event that someone spots something obvious.
Attachments
DC Voltage across P1 and P2 measures 6.8Vdc!
DRUIDAUDIO
Sorry, I forgot to note this below.
So it seems that there's plenty of DC (6.8V) measured across P1 and P2.
Not good obviously, but I'm not sure where that leads me next...
DRUIDAUDIO
Sorry, I forgot to note this below.
So it seems that there's plenty of DC (6.8V) measured across P1 and P2.
Not good obviously, but I'm not sure where that leads me next...
Resistors seem to measure okay...
I am currently checking resistor values as quite impressively, this amp has clear component values stated in every position.
I haven't found any duds yet, but this assumes (for the moment) that they are fully connected beneath the circuit boards - which are still in place.
I am currently checking resistor values as quite impressively, this amp has clear component values stated in every position.
I haven't found any duds yet, but this assumes (for the moment) that they are fully connected beneath the circuit boards - which are still in place.
I am sorry if I will say this, did you check your input, if something with DC voltage is connected to your input amplifier will shift output also to some DC voltage. Try to disconnet input terminals and then check is it working. Maybe it is some DC mV on your preamp output. This is DC amplifier.
Protection Circuit active, even with no input connected...
Thanks PITBUL.
I double checked my input - which is currently a CD-player direct - with no change of status.
Because this amp features separate GAIN pots, it can be run very successfully without a preamp with all of our speakers.
So, the Protection Circuit remains active, effectively locking the amp up and preventing any warm-up or anything.
Thanks PITBUL.
I double checked my input - which is currently a CD-player direct - with no change of status.
Because this amp features separate GAIN pots, it can be run very successfully without a preamp with all of our speakers.
So, the Protection Circuit remains active, effectively locking the amp up and preventing any warm-up or anything.
Protection Relay perhaps?
I did wonder if the early 1980s Protection Relay may need to have the contacts cleaned - and was therefore causing the problem.
But thinking this through, I estimate that the Protection Circuit wouldn't work at all, if this were in fact the issue. Perhaps I have this wrong?
In any event, I have given the Relay itself a bit of a firm "tap" on the head - as you do - just to see if it is somehow "stuck".
No change of status. Protection Circuit remains active, locking the amp up completely.
I did wonder if the early 1980s Protection Relay may need to have the contacts cleaned - and was therefore causing the problem.
But thinking this through, I estimate that the Protection Circuit wouldn't work at all, if this were in fact the issue. Perhaps I have this wrong?
In any event, I have given the Relay itself a bit of a firm "tap" on the head - as you do - just to see if it is somehow "stuck".
No change of status. Protection Circuit remains active, locking the amp up completely.