Hey all!
So I am looking at "building" some Class D IRS 2092 based amps (the LJM L15D to be specific) and plan on using an SMPS PSU.
I would like to run between 4 and 6 amp boards off a single PSU, 2 of those amp channels will likely be used for subwoofers.
As far as I understand there are 3 ways to resolve bus pumping issues:
1. Run the amps in mono
2. Invert signal on the 2nd channel
3. Add capacitors to the PSU
Now option 1 is not going to work as I would need to double the amount of amp boards required.
Option 2 is what I am looking at, I will have a MiniDSP unit so inverting the signal on the MiniDSP should avoid the need for any op-amps which invert the signal for me. I can then simply invert the speaker outputs on the amp to get bring the polarity back in phase on that channel.
The issue is I know and understand how to do this for 2 amp channels, one channel will have the signal in phase and the other channel have the signal out of phase. This leads to the bus pumping being out of phase and causes a cancellation.
However when running more than 2 boards, I am not sure how this will work or whether it is even possible to use this signal inversion method to control bus pumping if using more than 2 boards on a single PSU?
Option 3 is still an option, however since I am still brand new to amp building and still learning I would need assistance from some friendly folk here on how much to add and how to wire it up correctly. Reading on some international forums a few members had concerns that the SMPS PSU might not be happy with some large caps being added, specifically around start up.
I tried asking for assistance regarding option 2 on the international forums, but have not had any response. So I really hope someone here can assist and point me in the right direction. If option 2 is not possible with more than 2 channels then that is fine at least I know and understand for future reference and then I will need some assistance regarding option 3.
Regards,
Psy
So I am looking at "building" some Class D IRS 2092 based amps (the LJM L15D to be specific) and plan on using an SMPS PSU.
I would like to run between 4 and 6 amp boards off a single PSU, 2 of those amp channels will likely be used for subwoofers.
As far as I understand there are 3 ways to resolve bus pumping issues:
1. Run the amps in mono
2. Invert signal on the 2nd channel
3. Add capacitors to the PSU
Now option 1 is not going to work as I would need to double the amount of amp boards required.
Option 2 is what I am looking at, I will have a MiniDSP unit so inverting the signal on the MiniDSP should avoid the need for any op-amps which invert the signal for me. I can then simply invert the speaker outputs on the amp to get bring the polarity back in phase on that channel.
The issue is I know and understand how to do this for 2 amp channels, one channel will have the signal in phase and the other channel have the signal out of phase. This leads to the bus pumping being out of phase and causes a cancellation.
However when running more than 2 boards, I am not sure how this will work or whether it is even possible to use this signal inversion method to control bus pumping if using more than 2 boards on a single PSU?
Option 3 is still an option, however since I am still brand new to amp building and still learning I would need assistance from some friendly folk here on how much to add and how to wire it up correctly. Reading on some international forums a few members had concerns that the SMPS PSU might not be happy with some large caps being added, specifically around start up.
I tried asking for assistance regarding option 2 on the international forums, but have not had any response. So I really hope someone here can assist and point me in the right direction. If option 2 is not possible with more than 2 channels then that is fine at least I know and understand for future reference and then I will need some assistance regarding option 3.
Regards,
Psy
