Behringer iNuke NU3000 w/o any fan...?

[ashok]

Maybe I was hasty about the sound of 'vocals'. On some albums it sounds hard compared to what I was used to . This certainly will take time to evaluate !

 

[compressit]

I use a 3000 DSP for my bass guitar rig @8 ohm. It is almost disturbing how cool this amp runs. Even after long hours at substantial volume.
Also, to all the iNUKE naysayers and name callers. You really need to look and listen to this package. It is one of the best values in pro audio.

 

[ashok]

Listened to the nu3000 for three hours last night . As I said the bass and other percussion instruments seem to have more bite which seems to be the trademark of most classD amps I have heard. Voice is good but I think it differs from my usual ss/AB amp. HF is certainly different on my other amps. They sound more 'airy' depending on the signal. But I could be wrong. Can't make a final conclusion unless I compare them side by side.
However I am happy I bought it. It's a good amp!
The fan IS terribly noisy. Not noticeable when the volume is up but very audible in between tracks and VERY obviously noisy when you go near the amp. Not acceptable at all . This surely needs to be fixed. Even my PC's fan is less noisy !

 

[Soldermizer]

Thus my original inspiration to remove the fan entirely

 

[JonasKarud]

Thus my original inspiration to remove the fan entirely

Or use very quiet Nexus fans: Nexus Quiet Fan | The World's Quietest Fans | 80MM Real Silent Case Fan | Ideal for a Quiet PC

 

[Soldermizer]

Other than putting on some easy adhesive heat sinks, how complex would it be to put the heat producing MOSFETS (HEXFETs actually) onto a large heatsink? This is probably beyond my competence. I have seen tutorials for peope who did this with PC power supplies (link).

Fanless Power Supply: Marko's Homebrew | silentpcreview.com

In the case of the Behringer NU3000, the 4 "factory" heat sinks are "live" so I guess one just cannot bolt them to the case or a large heatsink. Isn't this what mica plates are for? I am not brave (foolhardy) enough to dismount the working MOSFETS. Anyone else here want to meet that challenge?

 

[ashok]

I guessed the current 'heat sinks' were live so each one will have to be independent of the others. Since there is such a huge space above the transistors , one should design a heat sink that fits in 'vertically' and painted matt black. Rough idea is to attach it to the vertical section using heat sink compound and a screw setup to clamp it tight and extend upwards as fins to cool it. Maybe I should run it without the fan and see what else runs hot. Looks like the smps also has two transistors with heat sinks. A very quiet low speed fan might still be essential ?

Can anyone run this amp without the fan and some reasonable high load ( 100 watts per channel ? ) and take an IR picture of the whole board ?

 

[Soldermizer]

You ask much.

My test equipment is limited, but I guess this could be a valid test: put a VOM across one speaker terminal, set to AC volts, and play a sine wave and try at increasing volume, noting the voltages, until the amp goes into protect mode.

I will be glad to do this, but have a girlfriend visiting and also will have to move the pets out of the room so they don't go nuts.

I would be surprised if fanless will allow as much as 100 watts RMS/channel but who knows?

 

[Soldermizer]

For those interested, I did a photo tutorial of modding my 2nd NU3000. It is a Word Doc, available here:

Index of /shared/Behringer NU3000 fanless

 

[Soldermizer]

OK, screw the girlfriend (So to speak), and the pets, I did a quick test. My fanless NU3000 will put 13.2 VAC (50 Hz tone) into 4 ohms load (assumed, two Bose 901 II per channel), for a minute or two before one channel goes "red." Using the Power = V^2/R formula, that would be about 43 Watt/channel. Room temp was about 72 deg. F. I may do more runs to see what the max. I can do without protect coming on.

 

[ashok]

I would have used a heat sink with a much larger surface area. The ones you used seem to be quite small. Can't determine much from the picture. I was considering something much larger physically. If (!) I get it done , I'll put up some pictures. I think I need to measure temperatures first. Will bring out my temp meter . Need to get some 100 watt dummy loads first.

 

[Soldermizer]

The adhesive heat sink was suggested by some one at (I think) Home Theater Shack. Ashok, I look forward to your (or anyone's) mods to the amp.

Here is a link the the HTS discussion mostly about different fan options:

http://www.hometheatershack.com/for...nu1000-amp-amplifier-fan-swap-how-w-pics.html

 

[JonasKarud]

What about an oilcooled Inuke?

Vegetable Oil Pc whit test of temperature pc olio - YouTube!!!!!!!!!!!!!!

 

[Soldermizer]

Hmmm. Tempura HEXFETs .... yummy!


Some more data points:
Freq = 25 Hz; 18 V = less than 1 minute to protect;
12.6 V Same;
9.61 V = protect after about 1:30 (MM:SS);
7.4 V (29 Hz), still ok up to 10:00 without any protect. ( = 14 watts RMS);

 

[Soldermizer]

I watched a few videos of the "oil cooled PC" concept. I didn't realize it was such a hobby. I did a search for similar amplifier but found none. In principle it would work the same for electronics such as the NU3000. I would try it if I had an application that demanded maximum power from the amp.

Clean-up: I wonder how much of a hassle it is to clean the oil off the electronics? A lot, I bet. Just washing pots and pans that have had oil in them seems a challenge. On the other hand, I have washed (with water and detergent) many electronic items, mostly with success.

 

[ashok]

If you have a leak and oil spills all over the board you will hardly be able to clean it up properly. The oil will also attract dust and it will cake up at points along the board. I think it will be a total disaster ! I would never risk it on the nu3000. PC over clockers do all kinds of crazy things. Crazy procedures go hand in hand with disaster , only a fine line divides them. This is a classD amp. It shouldn't need that level of cooling !

 

[Soldermizer]

I would guess the entire amp would be submerged in oil. In that case, your concern about a spill applies. However, the amp would only be removed for "scheduled maintenance." Dust and dirt would not necessarily be a problem. However, how to clean off the oil would be. Unlike some of my crazy ideas, I am not likely to try this one ... I hope!

 

[Soldermizer]

Oh darn it, the experimenter instinct has taken over. I am now the proud owner (?) of a tote (storage box) with gallons of mineral oil covering the guts of my desktop PC. It works (how long is anyone's guess.) I thought that disconnecting the one remaining fan (the CPU cooler) would give me a silent PC. No. The HDD still makes audible noise. I guess a SSD will soon be on order. So far the NU3000 remains safe and dry on the shelf.

 

[Kjeldsen]

I have made a few "silent" PC's and it's mot the fans that at noise. Keep a fan or two but large silent ones. I get rid of the small 1 inch fan in the PSU and replace with 80 mm/3 inch silent fan, and another 80 mm/3 inch in the cabinet to get som flow. Keep fan speed at a minimum, and the fans will be inaudible.

I found a 3,5 inch samsung disk that was very silent. Otherwise 2,5" disks are more silent that 3,5 inch. SSD of course dead silent and fast, but expensive.

I have a nexus fan right now, as mentioned i a answer above. It's very silent, even at middle fan speed.

 

[JonasKarud]

Oh darn it, the experimenter instinct has taken over. I am now the proud owner (?) of a tote (storage box) with gallons of mineral oil covering the guts of my desktop PC. It works (how long is anyone's guess.) I thought that disconnecting the one remaining fan (the CPU cooler) would give me a silent PC. No. The HDD still makes audible noise. I guess a SSD will soon be on order. So far the NU3000 remains safe and dry on the shelf.

I know the feeling! Was the oil expensive? Can you notice any change in oiltemp when the computer is working?