Experts I NEED your help here
I bought an ada1200 from adire about 2 months ago. When I recieved it and hooked it up flipped the switch and nothing happened, the light didnt even flicker, no noises, nothing.
Well I figured the simplest explination, the fuse was blown. Finding the fuse was a task, but when I did, sure enough the filament was vaporized.
Well it just so happens that adire like to use parts on their products that are extremely difficult to find, such as 20x5mm 125v 10amp fuses. So I request for them to send me some replacement fuses(which took at least a month and a half).
In the mean time I go up to radioshack and see what they have similar and the best I can find is a 6.3amp fuse. Well those didnt work exactly. When the amp powered up it blew a fuse. The light did flicker though, so I popped in another fuse. Flipped the switch and it turned on.
The amp worked once it had been powered on. But after letting it sit for a while it blew more fuses upon powerup. I figured this was because I was using 6.3 amp fuses, BUT when I finally got the 10amp fuses from adire the SAME thing happened.
Now If you ask me I'd figure something is faulty in the power supply, but not knowing much about amps I have no idea what would cause this. Its a strange symptom to me because it only blows fuses upon powerup and not under operation.
I'll probably just end up sending it back to adire, but I dont feel like paying shipping again, and I dont feel like waiting indefinately.
If anyone has a thought on what it could be I'd much appreciate it
I bought an ada1200 from adire about 2 months ago. When I recieved it and hooked it up flipped the switch and nothing happened, the light didnt even flicker, no noises, nothing.
Well I figured the simplest explination, the fuse was blown. Finding the fuse was a task, but when I did, sure enough the filament was vaporized.
Well it just so happens that adire like to use parts on their products that are extremely difficult to find, such as 20x5mm 125v 10amp fuses. So I request for them to send me some replacement fuses(which took at least a month and a half).
In the mean time I go up to radioshack and see what they have similar and the best I can find is a 6.3amp fuse. Well those didnt work exactly. When the amp powered up it blew a fuse. The light did flicker though, so I popped in another fuse. Flipped the switch and it turned on.
The amp worked once it had been powered on. But after letting it sit for a while it blew more fuses upon powerup. I figured this was because I was using 6.3 amp fuses, BUT when I finally got the 10amp fuses from adire the SAME thing happened.
Now If you ask me I'd figure something is faulty in the power supply, but not knowing much about amps I have no idea what would cause this. Its a strange symptom to me because it only blows fuses upon powerup and not under operation.
I'll probably just end up sending it back to adire, but I dont feel like paying shipping again, and I dont feel like waiting indefinately.
If anyone has a thought on what it could be I'd much appreciate it
Does it use a switch mode power supply (ie. no big torodial transformer is visible)? If not the inrush current from the big transformer is what's tripping these fuses. Any transformer >600VA needs a form of softstart to limit the inrush current, that part of the amp could be malfunctioning. If you're unsure what type of power supply is used a picture would be helpful.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Hi,
It's caused by two things.
The core of the toroid has excellent memory and so if the current at turn on is out phase with the current at prior turn off the core is essentially saturated and heavy currents can flow as it looks like a short. Rule of thumb is it's not a concern until greater than 300VA, yours would be well over that, probably being a 1 200VA.
Now the other issue is the cap bank in the power supply. At first turn on they'll be empty and pose a heavy load, if the core appears saturated on top of that depending on the phase of the currents as I mentioned it will exacerbate the issue.
This is very commonly referred to as inrush current. The more powerful the supply, bigger transformer, more capacitance, the worse it is. The cure for it is commonly known as a soft start circuit, which limits inrush current at power up. You can both see and test this theory for yourself by making a power cord with a 100W lightbulb in series.
When you turn it on the high inrush current will cause the light to glow brightly for a second(which limits the inrush current as it does so), as the core resets if it has to and the caps charge up the current draw is reduced and the light will go dim again. Odds are the light will only glow when the caps are discharged after a few minutes of being turned off.
The reason you got it to work by sacrificing a fuse is because that initial rush that blew the fuse would have charged the caps somewhat, so they'd present less of a load. If you then change the fuse fast enough before the charge can bleed down again, you stand some chance at having it power up without blowing another fuse.
By leaving it turned off a few minutes the caps will drain through bleeders or the amplifiers biasing circuitry etc. So the next time you go to turn it on that high inrush is back again and your fuse blows.
It seems Adire failed to mention this requirement in their manual, they probably should have included the soft start circuitry themselves, but since they didn't, you'll have to find your own soft start solution, or make one.
Regards,
Chris
It's caused by two things.
The core of the toroid has excellent memory and so if the current at turn on is out phase with the current at prior turn off the core is essentially saturated and heavy currents can flow as it looks like a short. Rule of thumb is it's not a concern until greater than 300VA, yours would be well over that, probably being a 1 200VA.
Now the other issue is the cap bank in the power supply. At first turn on they'll be empty and pose a heavy load, if the core appears saturated on top of that depending on the phase of the currents as I mentioned it will exacerbate the issue.
This is very commonly referred to as inrush current. The more powerful the supply, bigger transformer, more capacitance, the worse it is. The cure for it is commonly known as a soft start circuit, which limits inrush current at power up. You can both see and test this theory for yourself by making a power cord with a 100W lightbulb in series.
When you turn it on the high inrush current will cause the light to glow brightly for a second(which limits the inrush current as it does so), as the core resets if it has to and the caps charge up the current draw is reduced and the light will go dim again. Odds are the light will only glow when the caps are discharged after a few minutes of being turned off.
The reason you got it to work by sacrificing a fuse is because that initial rush that blew the fuse would have charged the caps somewhat, so they'd present less of a load. If you then change the fuse fast enough before the charge can bleed down again, you stand some chance at having it power up without blowing another fuse.
By leaving it turned off a few minutes the caps will drain through bleeders or the amplifiers biasing circuitry etc. So the next time you go to turn it on that high inrush is back again and your fuse blows.
It seems Adire failed to mention this requirement in their manual, they probably should have included the soft start circuitry themselves, but since they didn't, you'll have to find your own soft start solution, or make one.
Regards,
Chris
Based on the information you've given .... yeah.
Is there any delay from when you turn it on to when the fuse blows? Do you hear a relay trip right before it blows after that delay? That'd maybe be indicative of a failed soft start circuit. Say a power resistor that failed open, when the relay trips to bypass it a short time after turning it on inrush still occurs just like if you didn't have a soft start circuit.
Why don't you contact them with your new found knowledge and see what they have to say about it. Really, they should have mentioned the requirement for it in their manual if they did not include it.
Regards,
Chris
Is there any delay from when you turn it on to when the fuse blows? Do you hear a relay trip right before it blows after that delay? That'd maybe be indicative of a failed soft start circuit. Say a power resistor that failed open, when the relay trips to bypass it a short time after turning it on inrush still occurs just like if you didn't have a soft start circuit.
Why don't you contact them with your new found knowledge and see what they have to say about it. Really, they should have mentioned the requirement for it in their manual if they did not include it.
Regards,
Chris
Errrrrmmm..... well you know what the problem is now at least. I'm not so sure their advice is the greatest however.
Inrush surge currents can more than surpass 15 amps ... dorks. They should have at least recommended a SLOW BLOW. Inrush can even trip a 15amp breaker if it's not delayed action.
How much variation do they expect on mains voltage? Very strange thing to say. I'd be tempted to give it right back to them, but you may now make your own educated decision.
Regards,
Chris
Inrush surge currents can more than surpass 15 amps ... dorks. They should have at least recommended a SLOW BLOW. Inrush can even trip a 15amp breaker if it's not delayed action.
How much variation do they expect on mains voltage? Very strange thing to say. I'd be tempted to give it right back to them, but you may now make your own educated decision.
Regards,
Chris
Is there any way to create a softstart outside of the amp? Just something that limits the current draw? 15amp fuses sized 20mmx5mm seem to be impossible to find also...
probably the easiest thing would be getting permission from them to change the power imput plug/fuse holder to a power imput/breaker. That way I can just flip the breaker twice to turn it on and no worries about softstart, or blowing fuses. If a breaker trips, you just gotta reset and flip it on again, much better than fuses!
probably the easiest thing would be getting permission from them to change the power imput plug/fuse holder to a power imput/breaker. That way I can just flip the breaker twice to turn it on and no worries about softstart, or blowing fuses. If a breaker trips, you just gotta reset and flip it on again, much better than fuses!
Hi !
I have planned to recommend an ADA sub amp to a friend who plan to build a sub, thus I was curious when I saw that you had run into problems.As far as I have read about it , it´s power amp part is a half bridge class D one running at 60 kHz switching frequency, and it (definately) seems to use a non-switching power supply.
A quote from the manual:"Only use the orginal size/value of fuses when replacing blown fuses".
If the unit uses a softstart , ordinary fuses(not slow blow) should be sufficient, because the purpose of the soft start is to limit the inrush current , when powering up.
Without a softstart, the big toroid transformer represents nearly a shortcut to the mains when starting up, primarely because no electromagnetic field has yet been built up in its core.It is,as well, of importance when in the AC cycle you happen to turn it on,thus
it´s quite possible that the fuse wouldn´t blow, if you hit the "zero crossing".
My guess is, that a softstart is included, but that it may not work.
An external softstart is possible to use , but you have to implement it in a way that doesn´t void the warranty.
A working softstart is usually recognized , by a clicking sound (from a relay ) after a second or so. The relay then bypasses the
resistor,which limits the inrush current; the resistor is placed in series with the primary winding of the transformer.
Faultfinding is a process , when hypothesis often are checked
one by one, thus the worst case is when several faults exist.
So let´s hope for a "simple" fault , and keep us informed.
manual
I have planned to recommend an ADA sub amp to a friend who plan to build a sub, thus I was curious when I saw that you had run into problems.As far as I have read about it , it´s power amp part is a half bridge class D one running at 60 kHz switching frequency, and it (definately) seems to use a non-switching power supply.
A quote from the manual:"Only use the orginal size/value of fuses when replacing blown fuses".
If the unit uses a softstart , ordinary fuses(not slow blow) should be sufficient, because the purpose of the soft start is to limit the inrush current , when powering up.
Without a softstart, the big toroid transformer represents nearly a shortcut to the mains when starting up, primarely because no electromagnetic field has yet been built up in its core.It is,as well, of importance when in the AC cycle you happen to turn it on,thus
it´s quite possible that the fuse wouldn´t blow, if you hit the "zero crossing".
My guess is, that a softstart is included, but that it may not work.
An external softstart is possible to use , but you have to implement it in a way that doesn´t void the warranty.
A working softstart is usually recognized , by a clicking sound (from a relay ) after a second or so. The relay then bypasses the
resistor,which limits the inrush current; the resistor is placed in series with the primary winding of the transformer.
Faultfinding is a process , when hypothesis often are checked
one by one, thus the worst case is when several faults exist.
So let´s hope for a "simple" fault , and keep us informed.
manual
After having look at this pictureplateamp it seems to me that no inrush limiter is used at all.
The easiest way to create one, is to add a NTC resistor in series with the primary windings of the transformer. Such a resistor has a relatively high resistance value when cold, and when it is warmed up by current running through it , the resitance drops significantly. It is not the best way , but it works.
As this plate amp is supposed to be left on all the time, another way to go , could be to add a resistor in series with the primary
winding, and manually bypass it after some seconds when powering up.
And I agree to what has been written about capacitors being charged by high current, and this is in fact a reason for using an inrush current limiting device. Capacitors don´t like high surges.
A soft start is a good thing , and if it isn´t included in your sub amp, I can´t see why.
The easiest way to create one, is to add a NTC resistor in series with the primary windings of the transformer. Such a resistor has a relatively high resistance value when cold, and when it is warmed up by current running through it , the resitance drops significantly. It is not the best way , but it works.
As this plate amp is supposed to be left on all the time, another way to go , could be to add a resistor in series with the primary
winding, and manually bypass it after some seconds when powering up.
And I agree to what has been written about capacitors being charged by high current, and this is in fact a reason for using an inrush current limiting device. Capacitors don´t like high surges.
A soft start is a good thing , and if it isn´t included in your sub amp, I can´t see why.
if I had a 10amp breaker on the amp it wouldnt trip the 30amp house breaker, I think that would completely fix the problem.
Actually a few times the fuse didnt blow... maybe like 3 times out of the 3 fuses I went through. But eventually powering it up once more blew it.
I did leave the amp on continuosly for a while, but after not using it for some time the back was a little warm to the touch. I dont know how much idle power it uses, but my guess is over 40watts and it just seems like a waste of power to have it running ALL the time.
I'm researching these softstarts to see if I can create one myself. Thanks for all the help guys
Actually a few times the fuse didnt blow... maybe like 3 times out of the 3 fuses I went through. But eventually powering it up once more blew it.
I did leave the amp on continuosly for a while, but after not using it for some time the back was a little warm to the touch. I dont know how much idle power it uses, but my guess is over 40watts and it just seems like a waste of power to have it running ALL the time.
I'm researching these softstarts to see if I can create one myself. Thanks for all the help guys
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