I am building an amplifier with IRS2092 stereo module and Accuphase C-3850 clone preamp.
Switching on is delayed about 3 seconds so there is no problem but after switching off a strong popping sound appears.
After switching off the power amp is still playing about 1-2 seconds but then very strong pop comes out.
IRS has speaker protection and obviously start up delay circuit so speaker protection module would probable not help, right?
How could I solve this?
Switching on is delayed about 3 seconds so there is no problem but after switching off a strong popping sound appears.
After switching off the power amp is still playing about 1-2 seconds but then very strong pop comes out.
IRS has speaker protection and obviously start up delay circuit so speaker protection module would probable not help, right?
How could I solve this?
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Hi,
I don't think the IRS2092 has power on delay, nor power off protection. It has over current protection.
You will probably need to implement the switch off protection (relay) to stop the pop sound etc. For switch on, it may be just the circuit design that causes the delay for switch on.
Regards,
Shadders.
I don't think the IRS2092 has power on delay, nor power off protection. It has over current protection.
You will probably need to implement the switch off protection (relay) to stop the pop sound etc. For switch on, it may be just the circuit design that causes the delay for switch on.
Regards,
Shadders.
As far as I can see the IRS2092 does not provide a mute function or mute input. You are then dependent on a speaker relay. The popping is likely caused by the pre-amp. But whatever, you'd need a speaker relay which turns off before the pre-amp or the power amp pops. That usually is arranged by a protection board which detects the unfiltered AC voltage. So the relay will fall off before the filtered DC voltage drops and thus before the pre or power amp pops.
PS. Posting a picture of your circuits here instead of a decent schematic wiring diagram is an insult to electrical engineers. Do you think WE can understand something from a picture?
PS. Posting a picture of your circuits here instead of a decent schematic wiring diagram is an insult to electrical engineers. Do you think WE can understand something from a picture?
Hi, try to isolate the source of this pop.
If you disconnect the preamp and short the amp input, does it pop when power down?
Try again without the short, so leaving the input open.
If amp doesn't pop, then the source is the preamp, and you can work on it.
In this case, you can create a signal mute electronically to short the amp input or even interrupt the connection from preamp to amp.
At least you know you have enough time to work on this, since there is 1 to 2 seconds before the pop.
A simple speaker relay fed by that small transformer (rectified) you already have can do that. It will open as soon as AC is removed.
You need a normally open realy contact for this case (only closes when there is power).
There is a shutdown procedure for IRS2092.
There is more than one option to resolve your problem - try to find from where it comes first.
See figure 10 on the Infinion AN-1138:
https://www.infineon.com/dgdl/an-1138.pdf?fileId=5546d462533600a40153559a077610d1
There is more than one option to resolve your problem - try to find from where it comes first.
See figure 10 on the Infinion AN-1138:
https://www.infineon.com/dgdl/an-1138.pdf?fileId=5546d462533600a40153559a077610d1
Using the shutdown pin from a properly derived signal would be the best option. However, IR does not anywhere mention this function in the datasheet. It mentions that CSD is used for shutdown. What, where, how? The AN in the link you posted properly describes it. It also looks like it is published by IR so I think it is reliable. The datasheet is hopelessly limited. I would not dare to recommend the use of CSD without experimenting first. Or reading the AN.
I had looked at the component before as well. I think it is very interesting. It enables you to build an amplifier with real RMS watts instead of the Chinese designs. Like 400W with a 50 power supply. (Into 2 ohms, BTL and d=10%). Although building such a class D amplifier is no trivial task especially not with regards to PCB layout and wiring. IRS ought to publish at least a reference design. Most manufacturers of integrated class D power amplifiers do.
I hope you keep us posted on your progress.
I hope you keep us posted on your progress.
Thank you very much for all your replies.
As ron68 suggested I disconnected the preamp, shorted the amp input and there was no pop after shutdown.
Tried again without the shorted input with the same result - no pop !
So as you said the pop is caused by preamp.
From all your suggestions the most easy one for me is the speaker protection relay.
The mini transformer powering the preamp is 15-0-15 V so it is not suitable for speaker relay, is it?
But in power supply module there is +15V output powering the thermal speaker protection circuit in amp.
Can I use it for powering the speaker protection relay? Isn´t AC 12 V necessary for the relay?
Would you recommend something like this?
speaker protection relay
In this case do I need an independent AC power supply?
As ron68 suggested I disconnected the preamp, shorted the amp input and there was no pop after shutdown.
Tried again without the shorted input with the same result - no pop !
So as you said the pop is caused by preamp.
From all your suggestions the most easy one for me is the speaker protection relay.
The mini transformer powering the preamp is 15-0-15 V so it is not suitable for speaker relay, is it?
But in power supply module there is +15V output powering the thermal speaker protection circuit in amp.
Can I use it for powering the speaker protection relay? Isn´t AC 12 V necessary for the relay?
Would you recommend something like this?
speaker protection relay
In this case do I need an independent AC power supply?
I will keep you informed. 🙂
From the first impression it looks very good. The sound is very detailed with a lot of bass but also with clear and sharp highs. Mids are also very clear and detailed. Overall it is very good amp with a lot of power. The PSU is 1000W LLC Soft Switching (+- 70 V).
I was considering building an amp with TPA3255 but heard a lot about missing bass. Otherwise it should be very good amp too but I prefer IRS2092.
It depends on the relay power consumption.
Taking a quick look, a mini relay that handles 20A consumes 640mW (0.640/12=53mA.
You need to check how much current is available in this transformer in order to not interfer with the pre-amp.
It probably can be used (adjusted to the relay voltage). You only need to check if this voltage goes to zero faster that the preamp pops.
Sometimes the capacitors holds the voltage for some seconds. I'm afraid this +15V will last sometime - you can check with a voltmeter.
Relays can be AC or DC (you choose the relay).
The idea of a separate AC feed, even rectified, is the time to remove voltage from the relay.
It needs to be faster than the pre-amp pop.
If you can have a separate transformer just for the relay, you can rectify using low capacitance in order to quickly drop the voltage as soon as you turn the amp off. This is the simplest solution.
Another option, a bit more complex, is to build a circuit to sense the AC on the mini transformer (not draining any current) and then operate the relay when AC is gone. The relay would be fed by the +15V but switched according to the presence of AC on the mini transformer.
Another option is to move the potentiometer to the amp input (in between the preamp and amp).
In this case, you turn it to zero before powering down the amp (you ground the amp input before power it down).
It might interfer with the amp input impedance, so it needs to be check.
There are many options.
This relay delays the power on. The power off, will depend on how much capacitance is there.
You need quick power off.
The vendor mentions independent AC source.
I had the same problem with one of my irs2029 amps.
It turned out with very large smoothing capacitors the power supply voltage decays too slowly and the pop occurs.
I designed a small VCC voltage detect that once under 12 volts it shorts reset pin via an opto coupler but also through a 220r resistor.
Without the resistor it blew up the irs2092.
It turned out with very large smoothing capacitors the power supply voltage decays too slowly and the pop occurs.
I designed a small VCC voltage detect that once under 12 volts it shorts reset pin via an opto coupler but also through a 220r resistor.
Without the resistor it blew up the irs2092.
Ron, thank you very much for such complex answer. I apprecite your help very much.
And all others too.
The mini transformer is rated 5 W so it should be enough for both preamp and relay.
+15 V connector holds its voltage for some time so I can´t use it (thanks for the idea of meausuring it).
I will try to find some quick relay which could help me.
Once again thank you very much for your ideas and pointing me to right direction. 🙂
Very much appreciated.
And all others too.
The mini transformer is rated 5 W so it should be enough for both preamp and relay.
+15 V connector holds its voltage for some time so I can´t use it (thanks for the idea of meausuring it).
I will try to find some quick relay which could help me.
Once again thank you very much for your ideas and pointing me to right direction. 🙂
Very much appreciated.
Great solution but quite difficult for me.
And also too risky. 🙂
I have found an interesting video regarding switching off pop.
This is probably the same solution which Ron has suggested.
How to Fix Pop on Speakers
I have found the same modules used in above mentioned video.
relay
power supply
In that video the relay is used for pre amp (in my case) shutdown delay so the pop will come after power amp is already switched off.
It is quite reasonable solution. 🙂
As Ron has suggested, the the most easy way would be to use this relay to interupt the pre amp output (probably ground, right?) or
shorten the amp input which would make actually a MUTE function.
The relay needs 12 V so I will still need the aditional power supply for it as there is no 12 V output in my PSU.
What kind of power supply do I need? It should have a low capacitance, right? Would a simple 12 V transformer be ok? Or it needs to be rectified?
And what about the speaker protection?
Is it necessary if power amp module have theese protections (based on seller´s specifications)?
Temperature protection: The temperature of the radiator rises to 85 ℃, the protection starts automatically, and the power amplifier stops working.
After the radiator temperature drops, the power amplifier automatically starts to work.
Overload protection: overload will protect you!
Horn protection: The output has DC, the relay is disconnected, and the speaker is protected!
Anti-shock: NTC thermistor at startup to prevent inrush current!
Delay start of the relay.
relay
power supply
In that video the relay is used for pre amp (in my case) shutdown delay so the pop will come after power amp is already switched off.
It is quite reasonable solution. 🙂
As Ron has suggested, the the most easy way would be to use this relay to interupt the pre amp output (probably ground, right?) or
shorten the amp input which would make actually a MUTE function.
The relay needs 12 V so I will still need the aditional power supply for it as there is no 12 V output in my PSU.
What kind of power supply do I need? It should have a low capacitance, right? Would a simple 12 V transformer be ok? Or it needs to be rectified?
And what about the speaker protection?
Is it necessary if power amp module have theese protections (based on seller´s specifications)?
Temperature protection: The temperature of the radiator rises to 85 ℃, the protection starts automatically, and the power amplifier stops working.
After the radiator temperature drops, the power amplifier automatically starts to work.
Overload protection: overload will protect you!
Horn protection: The output has DC, the relay is disconnected, and the speaker is protected!
Anti-shock: NTC thermistor at startup to prevent inrush current!
Delay start of the relay.
Again I find it incredible, irritating and insulting to post a question here about an electronic circuit problem, and not even posting a schematic, but only a picture of a PCB. We, electronic engineers can't do anything without a schematic. Posting a picture of a PCB is posting a picture of a food dish and ask why it does not taste well, without providing the recipe.
So I don't quite understand why I am willing to take the time share my thoughts again.
I retract what I first said about controlling a speaker relay to avoid the pop. It is the second best solution.
That was before @ron68 showed that the IRS2092 has a mute function. The mute function is the way to go. The mute function was designed for that.
Unfortunately we know nothing about the circuit, how and if the mute pin can be accessed. Because there is no schematic.
Basic outline of the solution is to derive a DC voltage from the small transformer. Use a separate diode on one of the windings. Small filter, bleed resistor so the DC voltage falls within a few 100 ms. Use this as a control signal for the mute function. If there is a doubt about DC levels or ground problems, it is allowed to use a relay to signal the mute pin so as to avoid any of this problems. I don't know whether it is necessary, you have to be careful with power & ground connections on high power amplifiers, different power supplies, separate pre-amp and post amp etc. It is not something to do without careful consideration.
Interrupting or short circuiting the signal between pre-amp and power amp is generally a bad idea. You don't know what incredible loud pops that can introduce. If there are output and input capacitors on pre-amp and power amp it is guaranteed something will pop. But we don't know as there is no schematic.
So I don't quite understand why I am willing to take the time share my thoughts again.
I retract what I first said about controlling a speaker relay to avoid the pop. It is the second best solution.
That was before @ron68 showed that the IRS2092 has a mute function. The mute function is the way to go. The mute function was designed for that.
Unfortunately we know nothing about the circuit, how and if the mute pin can be accessed. Because there is no schematic.
Basic outline of the solution is to derive a DC voltage from the small transformer. Use a separate diode on one of the windings. Small filter, bleed resistor so the DC voltage falls within a few 100 ms. Use this as a control signal for the mute function. If there is a doubt about DC levels or ground problems, it is allowed to use a relay to signal the mute pin so as to avoid any of this problems. I don't know whether it is necessary, you have to be careful with power & ground connections on high power amplifiers, different power supplies, separate pre-amp and post amp etc. It is not something to do without careful consideration.
Interrupting or short circuiting the signal between pre-amp and power amp is generally a bad idea. You don't know what incredible loud pops that can introduce. If there are output and input capacitors on pre-amp and power amp it is guaranteed something will pop. But we don't know as there is no schematic.
Hello,
Here's the simplest option in order to not interfer with the circuit or take a deep dive in the IRS2092 details, preamp etc.
So, I think it's better to use relay on the speakers rather than between pre-amp and amp.
When AC is turn on, relays close and connect the speakers.
When AC is removed, relays will quicky be opened and amp will be disconnected from speakers before pre-amp pops, since as you described, it takes 1 to 2 seconds to happen.
If you play with discrete components, find below a suggested circuit. You can replace the single dual pole relay with 2 single pole relays.
If you prefer to work with modules, you need to find equivalent modules sold in the market.
You need a power supply module that doesn't have much capacitance in the output so as to quickly drop the output when AC is removed.
I believe that most very small 12V power supplies (up to 500mA) will have small capacitance in the output, specially the switched mode.
But, it's a module, so you have to buy and test if it meets your requirements, since we don't know what the designer used in the circuit.
Just make sure to choose an isolated mains module.
Regarding the relay module, I think you can use those relay boards sold in the market.
Just check the connections, voltages etc.
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