24 Volt Panaflo M1A

al bundy · Post by **al bundy** » Fri Jul 25, 2003 8:09 pm

Has anybody tried one of these fans yet?

Word around here lately seems to indicate they are very nice and quiet when they are run at 12V or less (?)

I personally always hear a ticking sound from an undervolted 12V L1A. If these 24V M1A fans don't tick when undervolted, and are more quiet than our beloved reference fan, then I guess I'll just have to convert!

Post by **Ralf Hutter** » Sat Jul 26, 2003 5:28 am

"Word around here lately"

That's a new one on me. All I've ever seen is people trashing the noise of the 24V Panaflos when you try and run them at low voltages. Supposedly they tick like crazy plus have a lot of extra electrical and bearing noise that you don't have with a regular 12V L1A. The only time I've seen anyone advocating their use is just lately when Dorothy started selling them.

I may be totally out in left field though, but that's what I remember....and I'm too lazy right now to search for posts to backup my claims!

Post by **Rusty075** » Sat Jul 26, 2003 6:22 am

They blow too. (heehee)

Although I think some of my anger at them comes from my accidently buying 3 of them, when I thought I was buying 12v L1A's.

But yes, at 12v or lower the 24v fans produce very noticable IC clicking, as well as having more bearing noise an 12vL1A's.

Duncan · Post by **Duncan** » Sat Jul 26, 2003 6:38 am

From Dorothy's for sale thread:

"Some notes about integration:

---- they are VERY quiet, no acoustic artefacts
---- they are not the 24V-L1A (not usable & very different)"

---

Has anyone tried the 24v M1A?

grambr · Post by **grambr** » Sat Jul 26, 2003 6:02 pm

I just tried a used 24 v M1A, which I got cheap in a second-hand store.

It clicks really badly at 12 v and less + it vibrated like hell. This one was well used, so maybe it is not fair say they are all bad.

Same goes for a 24 v H1A which I picked up, only bearing noise and balance on this one were worse still.

12 volt M1A's, which I just fitted today (bought in the same junk shop) are working great though ... 2 in series for the case and one at 9v on the cooler.

Con't compare to L1A's, as I can't get them here in Brazil.

al bundy · Post by **al bundy** » Sat Jul 26, 2003 7:55 pm

Ralf Hutter wrote:...The only time I've seen anyone advocating their use is just lately when Dorothy started selling them...

Yes Ralf, that's exactly what I'm referring to.

Rusty075 wrote:...I think some of my anger at them comes from my accidently buying 3 of them, when I thought I was buying 12v L1A's...

Rusty075, you actually bought the 24V L1A's right? (Instead of the 24V M1A's I mean) Correct me if I'm mistaken please...

Duncan wrote:From Dorothy's for sale thread:

"Some notes about integration:
---- they are VERY quiet, no acoustic artefacts
---- they are not the 24V-L1A (not usable & very different)"

Has anyone tried the 24v M1A?

Exactly. We are asking the same question.

grambr wrote:I just tried a used 24 v M1A... It clicks really badly at 12 v and less + it vibrated like hell... Same goes for a 24 v H1A... only bearing noise and balance on this one were worse still...

Finally, some direct experience with the particular fan in question.

Thanks for sharing that info grambr! It is very helpful.

Anybody else?

Post by **Rusty075** » Sat Jul 26, 2003 8:01 pm

Yes Al, I bought three of the #$&%#! 24v L1A's.

A word of caution to anyone who shops newegg: The 24v variety is the only type of L1A they sell. So do not just scan down the list quickly looking for "80mm L1A" Trust me, read those model numbers carefully!

al bundy · Post by **al bundy** » Mon Aug 04, 2003 1:02 am

OK then, so far only one person says they've actually tried these 80mm 24v M1A fans (?)

If anybody else does too, I hope you would please post your experience for us regarding their noisiness (or lack of)...

futureweaver · Post by **futureweaver** » Mon Aug 04, 2003 3:49 am

I have several of Dorothy's 24V M1As. Subjectively they're no more clicky than the (one) 12V L1A I have - I think this is the same noise she calls "bearing / IC farts" in this thread http://forums.silentpcreview.com/viewtopic.php?t=5544. I can hear it with the case side off and my ear 15cm from the fan, but with the case assembled it's not audible - the predominant noise is air turbulence.

Reading the various threads on this issue, my impression is that it varies with fan sample, age/history, enclosure, mounting characteristics, orientation, voltage, source impedance, and the phase of the moon (well, maybe not the last one...) So a large and well-controlled blind trial would be required to reach any firm conclusions. That's the sort of thing drug companies pay gazillions to do, so I guess we'll not see one on fans any time soon ....

It would be interesting to know if the UBC trial is blinded.

Wedge · Post by **Wedge** » Mon Aug 04, 2003 5:01 am

I've got a couple but I haven't tried them out yet. I will post back when I have some experience with them. Sort of waiting for a couple of other items to arrive in the mail before I open my case up to install anything.

futureweaver · Post by **futureweaver** » Tue Aug 05, 2003 6:11 am

Having just listened very carefully to my fans, stopping them one at a time by hand, the clicking from the 12V L1A @9V on the CPU HS is definitely a lot more noticable than from any of the 3 24V M1As @12V.

Post by **Rusty075** » Tue Aug 05, 2003 1:19 pm

Your L1A clicks at 9v? I've never had one that clicks at so high a voltage. Is it really old? It might be a defective fan.

futureweaver · Post by **futureweaver** » Tue Aug 05, 2003 1:25 pm

No, it's a new one.

Post by **Rusty075** » Tue Aug 05, 2003 1:28 pm

Do you have any other L1A's to compare it to? A new L1A should not click at 9v. You usually have to drop it down below 5v to start having any IC click to speak of.

Post by **Ralf Hutter** » Wed Aug 06, 2003 5:22 am

Remember, there seems to be a bunch of crappy 80mm L1As floating around lately. There's sort of a thread about them in the Classifieds section (I think).

futureweaver · Post by **futureweaver** » Wed Aug 06, 2003 6:47 am

a bunch of crappy 80mm L1As floating around lately

That was my point about sample variation.

I'm going to to replace the L1A with a tacho one anyhow, when Dorothy gets them in. Ideally I'd like to use a 92mm L1A (with or without tacho), but I can't find a UK source. Anyone know of one?

al bundy · Post by **al bundy** » Thu Aug 07, 2003 12:36 am

Hi futureweaver,

Keeping on topic here,

Do you have a fanmate (or other voltage controller), to try out different voltages on those 80mm 24v M1A's?

I am finding they are clicky at nearly all voltages - except within a rather tight voltage band somewhere between around 7-9 volts, wherein they are actually very quiet (and with no clicking at all). Outside this tight voltage range though, the clicking resumes.

Your experience (or anyone else's too please)?

futureweaver · Post by **futureweaver** » Thu Aug 07, 2003 1:08 am

Do you have a fanmate (or other voltage controller), to try out different voltages on those 80mm 24v M1A's?

Yes, I'm using this http://www.enermax.com.tw/uc-a3fatr2.htm. But a strange thing has happened. The 12V L1A has stopped clicking, and one (but not the others) of the 24V M1As has started. To answer your question, if I turn it down below about 8V it stops clicking.

I'm starting to think this really does depend on the phase of the moon ...

Update: the level of the noise depends on orientation. I have rotated the fan (it's the front intake) to the quietest position.

Post by **Ralf Hutter** » Thu Aug 07, 2003 4:04 am

futureweaver wrote: Update: the level of the noise depends on orientation. I have rotated the fan (it's the front intake) to the quietest position.

You mean rotated on it's axis, in otherwords the actual axis of the fan hub?

If that's the case, then "whoa!". There's something else to mess with.

futureweaver · Post by **futureweaver** » Thu Aug 07, 2003 6:15 am

Ralf wrote:You mean rotated on it's axis, in otherwords the actual axis of the fan hub?

I do. One orientation of the four was clearly the quietest, and another (the one it was in, as luck would have it) the loudest. I wouldn't be surprised if horizontal / vertical made a difference too.

In [i]Recommended Fans[/i] Mike, quoting JMC, wrote:In traditional fans, the most dominant acoustic noise is due to the fan's motor switching noise. The stator motion is a square wave that is switched on and off before and after the peak torque position. This motion causes a small amount of undulation in motor torque, producing an audible noise caused by the lower frequency commutation operation. Each small torque causes a minute contracting of the entire fan structure and results in an audible clicking noise while the fan is operating.

So I'm not really surprised if depends on orientation, mounting, temperature, etc.