The reason I asked that question is that the Parts Express Sure IRS2092 2X250w amplifier board (Sure Electronics AA-AB32291 2x250W IRS2092 Class-D Amplifier Board) is rated for 8 ohm loads (only). Doesn't play nice with 4 Ohm loads, so you might look there for the source of the problem. The load rating of this amp board seems to be very commonly overlooked... you could connect the subs in series for an 8 ohm load but you will need to increase the gain by 3dB to compensate for the lower total sensitivity.
I use the L15D and L15Dx2 by LJM, sold on Ebay to drive 4R loads with this power supply, although no true subwoofers.
I wired the subs in series, and unfortunately it didn't fix the problem. At low frequencies and moderate volume, I still get static/popping, and the power supply clicks while those notes are playing.
Any other ideas?
Thanks,
Scott
Any other ideas?
Thanks,
Scott
Well then it's likely that you are experiencing the bus pumping issue - the class D Sure amp is half bridge and that returns energy to the PS on low frequency signals. When the PS cannot "adsorb" this returned energy it increases the rail voltage of the PS, and this might be causing some protection on the PS to kick in.
You could:
Change to a conventional linear unregulated PS for the subwoofer
Use a different amp/PS combo for the subs
Use the two subs wired in series (8R series load) and use two 4R capable amps connected to the Abletec PS driven out of phase. This will not cause bus pumping.
To anyone still following, I tried the wiring in series again and it was much better than before. I think last time only one channel of the amp was on as I'm having issue with now two of the Sure IRS boards only turning one channel on until i turn the volume up to very high.
So, much higher volume before the bus pumping causes the rail to shut down briefly and the static/popping sounds are virtually gone - the channel just mutes for a second instead of the static noises.
I am in the process of adding 10,000uF to each rail so I will see how this does and if I can turn up the movies to greater volume than I would watch them at. I am predicting that it will give me the output that I was aiming for for subwoofer duty, so I will report back!
So, much higher volume before the bus pumping causes the rail to shut down briefly and the static/popping sounds are virtually gone - the channel just mutes for a second instead of the static noises.
I am in the process of adding 10,000uF to each rail so I will see how this does and if I can turn up the movies to greater volume than I would watch them at. I am predicting that it will give me the output that I was aiming for for subwoofer duty, so I will report back!
100% Success - the amp and power supply combo work VERY well with the capacitors added to the rails.
So for anyone looking to use this combo (if you can still find the abletec PSU anywhere), adding that extra capacitance has stopped any power supply clicking and has eliminated the static/popping and the PSU isn't cutting out on LFE passages at higher volumes.
So for anyone looking to use this combo (if you can still find the abletec PSU anywhere), adding that extra capacitance has stopped any power supply clicking and has eliminated the static/popping and the PSU isn't cutting out on LFE passages at higher volumes.
Can you post a picture of your updated version/design? I have 2-3 of these in the closet and would be interested in trying for a lesser powered subwoofer.
Paul, no problem.
Here's a quick schematic.
Honestly for the total of $70 bucks with the PSU and amp board, plus the caps (which were graciously donated to me by Jon Marsh from HTGuide) this is pretty good.
Also, it actually sounds so much better to use for my mains than my Pioneer AVR that I would definitely use it for that purpose as well.
Here's a quick schematic.
An externally hosted image should be here but it was not working when we last tested it.
Honestly for the total of $70 bucks with the PSU and amp board, plus the caps (which were graciously donated to me by Jon Marsh from HTGuide) this is pretty good.
Also, it actually sounds so much better to use for my mains than my Pioneer AVR that I would definitely use it for that purpose as well.
That's great to hear. What is the AC mV level ripple at the output when connected to an amp that is not playing? Did adding 10000 uF caps help? I was afraid that the SMPS would choke on a large capacitive load upon starting up. Did you have to add any current limiting power resistors between the SMPS and the big 10000uF caps? Which brand caps are you using?
@scottmilne831 thanks for the schematic, exactly what I needed (a visual). I agree with you on the sound, I have been running (2) LJM L25D boards full-range to bookshelves and I like them a lot, so much so I have stopped using my other amps.
Xrk971,
I have no idea!! I don't have a scope or any bench testing equipment, and honestly barely understand anything that I'm doing. I'm the benefactor of all the pooled knowledge on these boards. I didn't add any additional soft start or anything, but no weird sounds pops or noises on startup at all. Just wired those caps in without any additional pieces and seems to work very well. Definitely a huge improvement from just the PSU to Sure board. Also, wiring in series for 8ohm and in bridge mono mode helped prior to the caps being added as well.
I have no idea!! I don't have a scope or any bench testing equipment, and honestly barely understand anything that I'm doing. I'm the benefactor of all the pooled knowledge on these boards. I didn't add any additional soft start or anything, but no weird sounds pops or noises on startup at all. Just wired those caps in without any additional pieces and seems to work very well. Definitely a huge improvement from just the PSU to Sure board. Also, wiring in series for 8ohm and in bridge mono mode helped prior to the caps being added as well.
Sorry - brand is Nichicon caps, 100V polarized.
Here's a pic:
Imgur: The most awesome images on the Internet
Ignore the labels written on the bottom of the base as I had it labelled wrong. Use the diagram from the previous post.
Here's a pic:
Imgur: The most awesome images on the Internet
Ignore the labels written on the bottom of the base as I had it labelled wrong. Use the diagram from the previous post.
I just ordered 3 more of the 200w amps for total of 4 amps and 2 per supplies.. I will be using them with a minidsp for active speakers. Waiting for the new amps to arrive from china.
Has anyone tried these supplies with a class AB amp? I am thinking of using this with my VHex+ amp. Adding the power rail caps is probably a good idea.
Here is my amp with a linear PSU. The 53v rating is just about perfect for this amp.
Here is my amp with a linear PSU. The 53v rating is just about perfect for this amp.
Abletec works with VHEX+ class AB amp
The Abletec works with a class AB amp very well. I am using a Dx PSU with rectifier and filters to provide additional filtering of any potential switching noise and also to give it qnty 4 x 4700uF Nichicon caps. The ripple is now 22mV with no music playing (formerly 60mV ripple with a 250VA 25V transformer). The power output of the amp has been increased considerably going from 35v to 52v. Sounds very good, speakers are essentially silent when source is turned off. I have to put my ears next to the tweeter to hear anything (90dB sensitive speakers).
This is a great alternative to a $50 300VA toroidal transformer. If I were to use my CRCLC PSU, I think the ripple could probably be reduce to around 2 or 3mV.
So, it's confirmed that this PSU not only works for class D but also class AB. The heatsinks are now running much hotter. 80mA per transistor x 4 transistors x 52v = 16.6w dissipation at idle.
The Abletec works with a class AB amp very well. I am using a Dx PSU with rectifier and filters to provide additional filtering of any potential switching noise and also to give it qnty 4 x 4700uF Nichicon caps. The ripple is now 22mV with no music playing (formerly 60mV ripple with a 250VA 25V transformer). The power output of the amp has been increased considerably going from 35v to 52v. Sounds very good, speakers are essentially silent when source is turned off. I have to put my ears next to the tweeter to hear anything (90dB sensitive speakers).
This is a great alternative to a $50 300VA toroidal transformer. If I were to use my CRCLC PSU, I think the ripple could probably be reduce to around 2 or 3mV.
So, it's confirmed that this PSU not only works for class D but also class AB. The heatsinks are now running much hotter. 80mA per transistor x 4 transistors x 52v = 16.6w dissipation at idle.
Attachments
Using my custom CRCLC PSU filter after the Abletec, I get 1mV ripple now. That's 20ppm ripple (51v rails). 😀
Sweet - the speaker is as dead silent as I have ever heard it without a source playing.
This is the CRCLC design shown above:
Sweet - the speaker is as dead silent as I have ever heard it without a source playing.
This is the CRCLC design shown above:
Using my custom CRCLC PSU filter after the Abletec, I get 1mV ripple now. That's 20ppm ripple (51v rails). 😀
Sweet - the speaker is as dead silent as I have ever heard it without a source playing.
This is the CRCLC design shown above:
In the crclc circuit what is r5-8 for?
Sent from my iPad using Tapatalk so there will be spelling mistakes...
When the AC mains power is removed you want the PS caps to slowly lose charge over 30 seconds or more. Using resistors of several kilo Ohms and a couple Watts (e.g. 5W) rating is often included in the circuit used for this purpose. They tend to get warm...
You can make out two 5W sandcast wirewound resistors on each side of the circuit board in the picture.
R5-R6 are bleed off resistors and are 2.2k 2w these happen to be metal film resistors
R7-R8 are snubber resistors used with caps and are also 2w these happen to be metal film
R1-R2 are the 5w sandcast resistors (actually two 6.8R in parallel) and are 10w total - and they do get hot as all the current for the amp flows through them. They work with the big caps as part of the CRC filter.
Nite that if using Abletec or any DC supply, you can skip the diode bridge.
R7-R8 are snubber resistors used with caps and are also 2w these happen to be metal film
R1-R2 are the 5w sandcast resistors (actually two 6.8R in parallel) and are 10w total - and they do get hot as all the current for the amp flows through them. They work with the big caps as part of the CRC filter.
Nite that if using Abletec or any DC supply, you can skip the diode bridge.
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Ah, thanks for the reply. Typically I see bleed resisters at the load end so I was curious.
Sent from my iPad using Tapatalk so there will be spelling mistakes...
Sent from my iPad using Tapatalk so there will be spelling mistakes...
The Abletec works with a class AB amp very well. I am using a Dx PSU with rectifier and filters to provide additional filtering of any potential switching noise and also to give it qnty 4 x 4700uF Nichicon caps. The ripple is now 22mV with no music playing (formerly 60mV ripple with a 250VA 25V transformer). The power output of the amp has been increased considerably going from 35v to 52v. Sounds very good, speakers are essentially silent when source is turned off. I have to put my ears next to the tweeter to hear anything (90dB sensitive speakers).
This is a great alternative to a $50 300VA toroidal transformer. If I were to use my CRCLC PSU, I think the ripple could probably be reduce to around 2 or 3mV.
So, it's confirmed that this PSU not only works for class D but also class AB. The heatsinks are now running much hotter. 80mA per transistor x 4 transistors x 52v = 16.6w dissipation at idle.
Hi xrk, my pcb is on way 🙂
where do you find that ? I can't find it with google
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