The Behringer NU3000 arrived today. I needed "twist lock" speaker cables and what Radio Shack lacked, the pro audio store had. Presidents' Day is a holiday? OK, there was no mail today. Made my DIY cables and sure enough the new amp puts out a nice signal to my 4x Bose 901 II. But the noisy fan. It may or may not be variable speed, but even at start-up it's too noisy for me.
Consulting the wisdom of the great Google, I found such info as this DIY video:
Behringer iNuke Amplifier Fan Swap DIY - YouTube
While putting in a quieter fan is a worthy goal, left unanswered is the ultimate question( especially if I currently have no suitable new fan). Besides being emminently cheap, the quietest fan is no fan, of course. Why not disconnect and remove the old fan, its shroud, and for extra cooling, leave the lid off? Well, it works...at least 1/2 hour into a test. I am relying on the "thermal shutdown" failsafe if it gets too warm. This would be the most elegant solution...perhaps passive cooling will work because (1) no cover to impede the updraft, (2) this may be "pro gear" but it will be on its own shelf in a normal bedroom, not crammed in a rack of other heat-generating devices; and (3) the amp probably won't get pushed too hard in my bedroom, but I will blast it tomorrow.
Other than presumably voiding the warranty, I see no problem in doing this mod but one must keep in mind that the top is open and high voltages are exposed. 
If the Soldermizer fanless mod works, some type of vented cover would seem to fit the bill. So go to your drill press and start making the thousands of holes it will need
Last year I did a similar "ghetto mod" on a PC fan. See it here:
SPCR • View topic - Fanless PSU with (almost) no soldering for < $12
This mod has proven itself safe (or at least, didn't melt) in 8 months of use. I basically took a stock ATX PSU, opened up the case, removed the fan, put a resistor in its place to fool the shutdown and crossed my fingers. Also I disconnected a 2nd case fan in the PC box. One side panel of the case had to be left open to allow enough air in. The only fan remaining on that PC is the CPU fan.
If anyone is inclined to do a rigorous power test of these amps, perhaps do one with the fan disconnected to see what its limits are.
Consulting the wisdom of the great Google, I found such info as this DIY video:
Behringer iNuke Amplifier Fan Swap DIY - YouTube
While putting in a quieter fan is a worthy goal, left unanswered is the ultimate question( especially if I currently have no suitable new fan). Besides being emminently cheap, the quietest fan is no fan, of course. Why not disconnect and remove the old fan, its shroud, and for extra cooling, leave the lid off? Well, it works...at least 1/2 hour into a test. I am relying on the "thermal shutdown" failsafe if it gets too warm. This would be the most elegant solution...perhaps passive cooling will work because (1) no cover to impede the updraft, (2) this may be "pro gear" but it will be on its own shelf in a normal bedroom, not crammed in a rack of other heat-generating devices; and (3) the amp probably won't get pushed too hard in my bedroom, but I will blast it tomorrow.
Other than presumably voiding the warranty, I see no problem in doing this mod but one must keep in mind that the top is open and high voltages are exposed. If the Soldermizer fanless mod works, some type of vented cover would seem to fit the bill. So go to your drill press and start making the thousands of holes it will need Last year I did a similar "ghetto mod" on a PC fan. See it here:
SPCR • View topic - Fanless PSU with (almost) no soldering for < $12
This mod has proven itself safe (or at least, didn't melt) in 8 months of use. I basically took a stock ATX PSU, opened up the case, removed the fan, put a resistor in its place to fool the shutdown and crossed my fingers. Also I disconnected a 2nd case fan in the PC box. One side panel of the case had to be left open to allow enough air in. The only fan remaining on that PC is the CPU fan.
If anyone is inclined to do a rigorous power test of these amps, perhaps do one with the fan disconnected to see what its limits are.
The thermal protection is useless if you insist on running without the fan (!!!)
I have recently seen these "modifications" on youtube and they are painful to watch..
The issue is that the thermal protection systems rely on specific airflow across the components in order to achieve predictable thermal characteristics. Without this airflow certain components will heat far faster than normal, while the monitored components will stay cool.
Result: Something will probably go BANG before protection activates!
Your best option is to KEEP the current shroud and either run a quieter PC fan or install a resistor in series with the fan. Either way you don't want to push the amplifier.
I have recently seen these "modifications" on youtube and they are painful to watch..
The issue is that the thermal protection systems rely on specific airflow across the components in order to achieve predictable thermal characteristics. Without this airflow certain components will heat far faster than normal, while the monitored components will stay cool.
Result: Something will probably go BANG before protection activates!
Your best option is to KEEP the current shroud and either run a quieter PC fan or install a resistor in series with the fan. Either way you don't want to push the amplifier.
New class D amplifiers without heat-sinks are the most evolved (and evil) form of programmed obsolescence that I know. They are designed to fail after a few years (just out of warranty) due to thermal cycling, dust build up and corrosion. A fair engineer would never throw air directly at a PCB. This is easy money for a few ones today and lots of garbage and ruin for the planet and us tomorrow.
Consider adding some heat-sinks with thermo-conductive gap filler rather than keeping a fan blowing air directly at a PCB. This is not a trivial work, indeed, it's the work that Behringer was supposed to do.
Consider adding some heat-sinks with thermo-conductive gap filler rather than keeping a fan blowing air directly at a PCB. This is not a trivial work, indeed, it's the work that Behringer was supposed to do.
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I hope to learn more about the NU3000, such as specifically where are the thermal sensors? I intend to keep running it fanless right now. In its present use (a home stereo in a bedroom) it surely is not being pushed as hard as its typical user (e.g. a heavy metal bass player shaking books off the shelf on the other end of the house.)
Yes! That's it!!! The new improved iPuke NaUsea3000 -- a workhorse amp for the headbanging professional. If the Airbus A380-like sound of the cooling fan is objectionable, you may be trying to use this in a home environment. While it will certainly void your warranty if a fly so much as defecates on the unit, some modders replace the cooling fan with a less raucous one, or even remove it entirely. The thermal protection may or may not work in such cases. Please note that vomiting upon the unit will likely etch the aluminum (due to stomach acids). Such damage is not covered by the warranty.
If you run it fanless, keep your nose handy for smell of overheated electronics, even at idle.
Some components may need air cooling that are not in the output stage.
I ran my Peavey IPR 3000 fanless (by mistake while putting in a quieter fan); I could smell it and the thermal protection lights went on in less than a minute.
Some components may need air cooling that are not in the output stage.
I ran my Peavey IPR 3000 fanless (by mistake while putting in a quieter fan); I could smell it and the thermal protection lights went on in less than a minute.
I have repaired many amplifiers placed at bars and clubs and I know the kind of dense dust that builds up over time anywhere the air from the fan is hitting (had to clean it too many times). It's not usually a problem, at home it will never be, but in this case it's a semi-pro PA amp and there is exposed solder (no solder mask) with strong AC at a few hundred khz and +/-90VDC, it may be enough for some electrolysis fun.
Concerning idle operation without fan, due to class D nature, each of the 4 power devices near the fan can be easily dissipating 3W at idle, that's why some air is always required. Definitely best fix would be adding some heatsinking.
Concerning idle operation without fan, due to class D nature, each of the 4 power devices near the fan can be easily dissipating 3W at idle, that's why some air is always required. Definitely best fix would be adding some heatsinking.
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I got the NU3000 partly for fun. If I don't kill it, it will replace either a Sunfire (ca. 1996) or a Carver M400t (ca. 1984), both of which work well but are just "old." In building the Sunfire, based on the "white paper", Carver effectively used a class D power supply and a class AB power amp stage. Works, but huge!
I use a iNuke 3000DSP (modified with Nexus Low Noise fans) to drive a pair of bass dipoles with four Peerless 12"/channel. It holds the voice coils in a very firm grip, and it's the best amp I've tried so far! Its wonderful to be able to experiment with the built in crossover and equalizer in real time. The living room bass setup is very quickly done, using Holm for measurements.
But I've noticed, when I play illegally high, that the power meters indicate that the amp is near to its output limit. I wonder if its possible to add some capacitors across the power supply voltage to increase the short term power output on my iNuke3000?
But I've noticed, when I play illegally high, that the power meters indicate that the amp is near to its output limit. I wonder if its possible to add some capacitors across the power supply voltage to increase the short term power output on my iNuke3000?
nu3000
This a little off topic but since you are all looking at the insides of the nu3000 ,can anyone say if the psu can be switched for 230 v operation ( from 120V ) ? Or does it look like everything in the psu section is going to be different ?
I've seen some smps circuits where they just seem to operate a jumper to convert from 120 to 240 V. Unless of course I misunderstood what they had done !
I saw the video on youtube but couldn't see any 'simple' method by which the supply could be switched for higher voltage operation.
Thanks.
This a little off topic but since you are all looking at the insides of the nu3000 ,can anyone say if the psu can be switched for 230 v operation ( from 120V ) ? Or does it look like everything in the psu section is going to be different ?
I've seen some smps circuits where they just seem to operate a jumper to convert from 120 to 240 V. Unless of course I misunderstood what they had done !
I saw the video on youtube but couldn't see any 'simple' method by which the supply could be switched for higher voltage operation.
Thanks.
Update for anyone who might be interested.
Behringer wrote back saying that you can't change smps mains operation voltage easily......maybe that means you "cannot" change it ! They said use a step down transformer at the mains input for 230V operation of a unit set for 120 V.
Hmm ! ......I wish it had been easier than that. Maybe there is an easier way ! Buy from Amazon.de rather than Amazon.com ! Discovered that only yesterday .
Behringer wrote back saying that you can't change smps mains operation voltage easily......maybe that means you "cannot" change it ! They said use a step down transformer at the mains input for 230V operation of a unit set for 120 V.
Hmm ! ......I wish it had been easier than that. Maybe there is an easier way ! Buy from Amazon.de rather than Amazon.com ! Discovered that only yesterday .
Many electronic items, at least those sold in the USA, are not multi-voltage. On the other hand, some consumer items such as notebook PCs are often auto-voltage, even since the 1990s. Probably, a manufacturer deliberately makes an item single voltage to discourage "gray market" (e.g. Stax headphones, at least currently, are not adaptable voltage); also, as streamlined as production must be, a Co. like Behringer probably saves a dollar in parts that would otherwise make a unit multi-voltage. Would be an interesting DIY project to see what (if anything) can be changed to adapt (say) a NU3000 from USA to other voltage.
"I don't know what the world may need but some words of wisdom would comfort it,
I think I'll leave that up to someone wiser..." Cracker, "Teen Angst"
"I don't know what the world may need but some words of wisdom would comfort it,
I think I'll leave that up to someone wiser..." Cracker, "Teen Angst"
I finally had my first shut down with the fanless NU3000 (2nd specimen I have modified). I was listening to some very bass heavy music and one channel turned to "red" from the default "Behringer orange." I shut the amp down for several seconds and then back on (reboot?) and everything is fine since. No way to tell the cause but thermal is a good guess. Surprising it reset so quickly.
This cycling through 'thermal cut off' might drastically reduce lifetime of some components ?
At least a fan when it starts turning reasonably warm might be better. As you say it was playing loud and so you really can't hear the fan.
Maybe the fan should work with an spl sensor too. During the quiet parts it shuts off or turns real slow if the unit is still hot ! Might give a few extra years of life ?
At least a fan when it starts turning reasonably warm might be better. As you say it was playing loud and so you really can't hear the fan.
Maybe the fan should work with an spl sensor too. During the quiet parts it shuts off or turns real slow if the unit is still hot ! Might give a few extra years of life ?
You make a good point. Somewhere else, someone said that the MOSFET (HEXFET here) has a service life due to the heating and cooling cycles. So this may be a problem even with a stock unit. I am not sure how cheap the HEXFETs are, but maybe people should replace them before they fail (like we do with electrolytic capacitors)?
I've just got my nu3000dsp . The fan is VERY noisy ! Not acceptable at all in a home environment . Additionally it whines a bit and that makes it more obstrusive. I opened it up and found the power transistors have a u shaped metal tab soldered to them. They are real thin in guage and are chromed. I hope they are copper but didn't seem to have the pure copper look at places where it is scraped off.
The most effective passive heatsink would have to be attached to the vertical section that rises from the board. It would probably have to be finned to be most effective. I'll check the market to see what can be obtained to suit the location. Maybe a thick aluminum or copper strip attached to a finned setup.
What other parts get hot on the board ?
Even with a quieter fan it might be better if it doesn't run at normal listening levels. It can turn on progressively as the heat build up at high volume.
Is that a 12 V fan and does it have variable speed ?
So far the amp sounds nice. There is some hiss at the tweeter from about 6 inches away from the driver but none at my listening position 12 feet away.
Bass as in most class D amps I have heard is very clear cut. HF might not be like on a regular class A/AB amp. Need to do more listening tests after more burn in. But should be fine for a sub / upper bass which is why I bought it.
Voice sounds good too.
Haven't tried any DSP settings yet.
Any way to shut off those orange lights. It's too bright in a living room.
Does anyone know if the standard nu3000 sounds better than a nu3000dsp without the dsp circuit in the signal path ?
The most effective passive heatsink would have to be attached to the vertical section that rises from the board. It would probably have to be finned to be most effective. I'll check the market to see what can be obtained to suit the location. Maybe a thick aluminum or copper strip attached to a finned setup.
What other parts get hot on the board ?
Even with a quieter fan it might be better if it doesn't run at normal listening levels. It can turn on progressively as the heat build up at high volume.
Is that a 12 V fan and does it have variable speed ?
So far the amp sounds nice. There is some hiss at the tweeter from about 6 inches away from the driver but none at my listening position 12 feet away.
Bass as in most class D amps I have heard is very clear cut. HF might not be like on a regular class A/AB amp. Need to do more listening tests after more burn in. But should be fine for a sub / upper bass which is why I bought it.
Voice sounds good too.
Haven't tried any DSP settings yet.
Any way to shut off those orange lights. It's too bright in a living room.
Does anyone know if the standard nu3000 sounds better than a nu3000dsp without the dsp circuit in the signal path ?
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