Thoughts & Experiences regarding Nexus PSU?

DuckTape · Post by **DuckTape** » Mon Mar 17, 2003 2:36 am

Hello folks.

Would you be so kind as to share your thoughts and experiences regarding the Nexus NX 3000 (300W) PSU?

Have you found it to be a reliable and quiet PSU?

Thanks much!
DuckTape

miker · Post by **miker** » Mon Mar 17, 2003 10:32 am

I have no compaints about mine. (I won the NX3000 in the SPCR contest last month) I had a Seasonic 300 FS before that, and a modded Enermax before that. The Seasonic was a bit louder for sure, especially at the higher temps. The nexus is all I could want, except for a wire grill, which I my add later.

Vernacular · Post by **Vernacular** » Wed Mar 19, 2003 7:31 pm

I'm correct in assuming that the Nexus NX-3000 is ATX compatible? I looked through their website and didn't find anything confirming or denying it. Just want to make sure before I slap the money down.

crg · Post by **crg** » Thu Mar 20, 2003 12:32 am

Yes, it is ATX compatable I even installed one in one of my new Dell's and it works just fine. Very quiet also of course....

Vernacular · Post by **Vernacular** » Thu Mar 20, 2003 9:50 am

Thanks. I ordered mine last night. I can't wait to have a quiet computer again! The P.O.S. power supply (sparkle) that came with my case is so loud.

GamingGod · Post by **GamingGod** » Thu Mar 20, 2003 10:39 am

I thought sparkles were supposidly pretty good? Maybe you could just fanswap it.

davidhooper · Post by **davidhooper** » Thu Mar 20, 2003 1:37 pm

Miker, do you think you could describe the sound differences between the Nexus & Seasonic a bit more please?
What is the difference in quality of the sounds? Is the difference very much?

I just slapped down £50 for the Seasonic and am wondering whether to splash out for the Nexus. What do you think?

miker · Post by **miker** » Thu Mar 20, 2003 2:05 pm

Well let me tell you that I would never have bought the Nexus for the amount of price difference between it and the Seasonic.

The stock Seasonic fan has a definite "whippy" noise to it. I can't explain it. WHen I put my ear to it, it almost sounded like it had a little piece of grass in it. I replaced it with an NMB fan and cut out the stamped grill, replaced it with a wire grill. I was happy.

The nexus is definitely quieter than the stock SS, but not than my modded one.

Then I won the Nexus. I felt I had to use the $75 PSU, and use the Seasonic on perhaps my wife's PC.

johnc · Post by **johnc** » Thu Mar 20, 2003 10:02 pm

I have had the same experience as Miker.

The Nexus 3000 is a very nice, relatively quiet PSU. I was hoping for an even lower noise level, so I modded a Seasonic. The original fan was removed and an NMB 80mm fan was hot soldered/shrink-tubing'd to the original fan wire.

The resulting Seasonic is very, very quiet. The air coming out of the PSU exhaust grill is barely warm. CPU temp runs about 38-42C. This system, which incorporates a Silent-PC case, is nearly as quiet as the TK-300 system. The TK-300 system is essentially inaudible in ordinary use.

I am using the SLK-800 heatsink/NMB fan combination with PIII-S chips (2 systems), with very good results. No speed control is needed for this fan, which is very quiet at 12 volts. (In fact, SpeedFan does not appear to see this fan. I suspect this is due to relatively low RPM's at 12 volts.)

John Coyle

davidhooper · Post by **davidhooper** » Fri Mar 21, 2003 10:35 am

Hi guys.
Just out of interest, why have you both used NMB fans? I thought Panaflos were generally acknowledged to be the quiestest, though I've been out of touch with the forum for a while...

How difficult is the mod?

And doesn't it make you wonder why Seasonic don't just stick a quieter fan on in the first place?!

/dh/

ez2remember · Post by **ez2remember** » Fri Mar 21, 2003 11:55 am

johnc wrote:The original fan was removed and an NMB 80mm fan was hot soldered/shrink-tubing'd to the original fan wire.

I thought the Seasonic fan is connected to a 2 pin header which can be just pulled out and replaced with any fan that has 2 or 3 pins connector. I am wrong what I read.

miker · Post by **miker** » Fri Mar 21, 2003 1:15 pm

I thought the Seasonic fan is connected to a 2 pin header which can be just pulled out and replaced with any fan that has 2 or 3 pins connector.

True, the fan inside is on a 2-pin connector. The two pin connector is one of those little ones though. My panaflo connector wouldn't go even with excessive trimming, so I cut the cord on the NMB and spliced it into another dead fan I had removed from my old enermax (same 2-pin connector in there). I like the NMB since it is actually even lower RPM stock @ 12v than a Panaflo. As long as you don't try to move more than a decent amount of air, the NMB can be comparable or preferable to a Panaflo.

miker · Post by **miker** » Fri Mar 21, 2003 1:16 pm

And doesn't it make you wonder why Seasonic don't just stick a quieter fan on in the first place?!

I think they wanted to keep a certain amount of CFM to stay within safety tolerances. Just a guess though.

ez2remember · Post by **ez2remember** » Fri Mar 21, 2003 3:29 pm

miker wrote:
And doesn't it make you wonder why Seasonic don't just stick a quieter fan on in the first place?!
I think they wanted to keep a certain amount of CFM to stay within safety tolerances. Just a guess though.

Yes, its all to do with politics. It's to meet with all those safety standards. emissions etc, you see on the PSU. All rigorously tested to get their seal of approval.

johnc · Post by **johnc** » Fri Mar 21, 2003 7:20 pm

I think Miker is on the mark.

Tonight, I put a Panaflo FBA08A12L and an NMB 3110KL-04W-B19, both low-noise 80mm fans, side by side. Each fan was receiving 12.25 volts by multimetering.

At this voltage, the Panaflo was clearly noisier than the NMB, but it was also moving substantially more air. I would guess twice as much.

Next, I put a FanMate in the Panaflo circuit, and dialed it down until the noise from the two fans was very similar. The Panaflo matches the NMB noise level when the Panaflo is receiving between 7.5 and 8.5 volts.

It has been said repeatedly in these forums that a Panaflo run at 7 volts is very, very quiet. The NMB starts at about this level of quiet-ness, because it is not moving a great deal of air. As the Panaflo is dialed down to even lower voltages, it becomes virtually inaudible.

So the beauty of the NMB is that at 12 volts it is very, very quiet. It is not particularly well-suited to situations in which a lot of heat dissipation is required, since even at full tilt it doesn't move much air.

Whether the NMB meets your needs is entirely dependent on how much heat your system is generating and how cool your room is. I am using low-energy components in a 21C room, and the NMB at 12 volts does great.

Hope this is of use to you.

John Coyle

Post by **MikeC** » Sat Mar 22, 2003 11:10 am

John, you must have a better batch of NMBs than I do. I received 50 (to help with a company on testing the suitability & consistency of these low noise NMB fans). What I found:

1. Airflow is less less than Panaflo -- 1/2? I think more than that, not measured so not sure.

2. Blade/spin noise is lower -- most because it spins slower.

3. Bearing/electronic noise is louder -- almost all of my samples were marred by a kind of buzzy/hummy sound that became more audible as voltage was dropped. In other words, the noise was masked by turbulence/blade spin noise at 12V, but became more obvious & apparent at lower speeds. How audible this is depends on your particulars, but for me, the combination to too low airflow and extra buzziness makes the NMBs a 2nd choice. It's not that this noise is absent in Panaflos -- but there is a lot less of it, and somehow it is less buzzy even when it is audible.

As I said, it may be sample/batch variations that account for the differences in what we hear.

johnc · Post by **johnc** » Sat Mar 22, 2003 2:00 pm

This business about noise is tricky.

I went back to the bench, and tried to adjust the FanMate'd Panaflo voltage so that air flow was equal to an unregulated (=12.25 volt) NMB.

Mike, do you have a good way of measuring airflow? I have thought about simple means such as RPM measurements, little windmills and (I really like this one) rates of evaporation of water from a graduated beaker. The key step is measurement of fan noise levels at equivalent airflow rates.

And it gets trickier. As you have pointed out many times, the frequency signature of the sound coming from a fan will influence its nuisance value. Perception of sounds will depend on physical characteristics of the listener (does he have high-frequency hearing loss?), cultural factors (honest to Pete, the language you were brought up speaking will weight your sound recognition!), and other factors (what are the background noises in the room, is there harmonic resonance, etc.).

But wait, there's more. The angle of observation of the fan is important. There is "beaming" of high-frequency sounds, so that the relationship of the listener to the air-flow axis and the fan frame/motor become critical. I tilt the fan 90 degrees, and the bearing noise disappears, tilt it back and it's there again.

At any rate, with similar airflows (by the crude method of putting my hand s in front of each fan simultaneously), and listening with the fan frames parallel to the ground and blowing toward the ground, the NMB at 12.25 volts and the Panaflo at 9.5 volts make about the same noise, and both are felt to be very quiet. Shielded inside a computer case, blowing down into a SLK-800 heatsink, neither would add much to the noise level in a fairly quiet room.

Lower the Panaflo to 7 volts, and it is much quieter than the NMB, but it isn't moving much air. Which brings us back to the key point: How much cooling power is required for the system?

I am very pleased that we have reached the point that the options for quiet computing have greatly expanded. A year ago, our options were more limited, and these kinds of discussions might not have been nearly so useful.

John Coyle

Wedge · Post by **Wedge** » Wed Mar 26, 2003 9:00 pm

miker wrote:I have no compaints about mine. (I won the NX3000 in the SPCR contest last month) I had a Seasonic 300 FS before that, and a modded Enermax before that. The Seasonic was a bit louder for sure, especially at the higher temps. The nexus is all I could want, except for a wire grill, which I my add later.

I'm new so bare with me......but why does a wire grill matter? What's the advantage/disadvantage of having one, rather than having the Nexus 300 watt as it is?

smush · Post by **smush** » Fri Mar 28, 2003 6:56 pm

Sorry don't have time at the moment to read thru all prior posts, but wanted to share my initial impressions...

I have been using the Nexus 300 for about 3 days now, and have been quite pleased with it. My previous PSU was an Antec Trupower 430watt, which I thought was fairly quiet, just emitting a low/medium broadband noise, not high-pitched at all. The NExus PSU is probably a good 5-10 dba quieter. In fact it is practically silent. I have the Quietpc 300watt PSU in my other computer, and I think the Nexus is quieter. The only thing is, I have 5 case fans going (2 80mm panaflos in front, 2 80mm panaflos in rear, and 1 90mm papst fan blowhole), and also a 80mm panaflo on my heatsink! I thought with the NExus all noise would go away, but now all I hear is my casefans. Which is good, cuz now I am able to differentiate the noise. Before the Antec Truepower noise mixed in, it was hard to say.

The only bad thing about the Nexus is it doesn't come with enough 4-pin connectors. It was about 2 short of what I needed. I had to use two y-adapters. I do have quite of few devices though: 2 hard-drives, dvd-rom, cd-rw, 2 rear 80mm fans, 2 front 80mm fans on a single fan bay bus, and a 90mm blowhole fan. I am somewhat concerned about whether the NExus can power all of my stuff in the long haul, so far though it has been stable. My rig has an Athlon xp 2100+ tbred revision b cpu.

Is it worth it? I think yes, but don't expect your rig to completely become silent. I think it would be ideal in a case with just a single rear and single intake fan. If you have alot of case fans, like I do, it might not be worth it. Shoving it under your desk may be a better solution

miker · Post by **miker** » Fri Mar 28, 2003 7:25 pm

I'm new so bare with me......but why does a wire grill matter? What's the advantage/disadvantage of having one, rather than having the Nexus 300 watt as it is?

Well, some of this is science, some is just personal taste or plain obsessive compulsive behavior, but here goes:

1.) The stamped grill just looks *BAD* to me, I love the looks of the wire grill.

2.) Stamped grills create air turbulence, especially with higher CFM fans. Turbulence creates a "whooshing" sound and also inhibits air flow. Obviously, with a low voltage, hence low-CFM fan like what's in the Nexus, it will not be a big problem, (possibly none) but that's where the OC behavior comes in

3.) Conversely, wire grills allow air to move more freely, so airflow is improved overall , with less turbulence and noise. I tend to remove half the grills from my wire grills. That's how bad my brain is

Wedge · Post by **Wedge** » Fri Mar 28, 2003 10:48 pm

There is medication for that.

j/k, thanks for clearing that up for me. *must resist urge to consider stamped grills taboo*

EDIT/ I think the wire grills look better too.

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