NEW MFW-15 amps (May 2010) *pics* - Page 6

Your ratings have had widespread appeal, I think because of their detail and easy to understand ratings. Rather then noting what the latest version looks or appears like, second hand, why don't you test the new subs and publish the results. Not only would that lay to rest any speculation but it would provide a current comparison with the subs you will be selling in the near future.

The only thing I could match was the amp runs very cool, I have to agree, no matter how hard you push it, it doesn't even get warm, (of course, mine doesn't produce as much power either). So, I got amplifier dud number 7, great.

Thanks for posting your findings NicksHitachi!

Sorry to go slightly O.T. but this is amp related.

I've had a B stock MFW for about 5 weeks now. Mine has zero hum (my house was wired in '57), and has performed very well. But my amp stays warm/hot all the time. Even if i turn the switch to off for a day, the amp is still warm to the touch. I was getting ready to get a remote controlled power strip to completely cut power to the amp when not in use, but then I read where some of the amps were blowing when powered up.

For those who have blown multiple amps, are you leaving the amp in standby, powering it off with it's power switch, or completely cutting the power to the unit when it's not in use? And the same question for those of you who've had NO issues.

The heat is "normal" I wouldn't be surprised if the amp failures are not partially attributable to the heat the components of the amp are subjected to. I read somewhere that for every 10 degrees rise in temp was like 20% loss in lifespan of electrical components(or something like that), someone should take a temperature reading on those babies and see just how hot they are getting. Mine is VERY hot to the touch even in standby.

To address your question on powering off, I personally would not, mine make thumps, bumps, or ticks when I power them on from an off state. Because of this behavior I personally would not.

I've actually contemplated blocking off the back plate and moving the V2 amps outboard with wire mesh cages which would solve humm and heat. I may strongly consider this more after seeing how the V3 amps pan out.

My v2 amps (from Jul '09 forward) had issues with the auto shut off, ran very warm and every one that blew, blew on startup. Either way, I still power them on with a switched outlet to conserve.

I have no idea how long they will last, I have one v2 amp that is still running as designed and 6 that didn't.

Good luck.

I'm very interested in hearing your impressions on sound quality for the v3 amp. I'm going to call Kyle today and let him know I'm going to do the same thing you did tonight, if yours were essentially equal I should be able to post the exact difference at the same settings even if we don't have the same AVR.

He's now bringing out his own products. I don't think he wants to open the can of worms of reviewing or facilitating the review of "competitors" subs.

I certainly don't like wasting power, or having my amp hot/warm all the time, but your results have me hesitant to completely kill the power supply. I'm going to see if any others have similar results to report.

Maybe finding a way to cool the amp without killing the power will help prevent the failures.

When I had my duals I used to shut them off from a switchable power strip. Left both sub amp switches in auto on all the time. During power up no noise, when the subs came on after signal detection no noise. When I shutoff the power strip with the sub amp lights still green I got a very, very slight burble type of noise this is the way I always turned them off. When they were powered off with the sub amp lights red a loud type of noise. Did this because to me the amps were just too warm for my comfort. This is of course how my amps behaved both were v2 models. Like you never had any problems with mine other than the heat while in standby mode. Hope this helps.

There is basically no difference in power consumption leaving them on or in auto mode. Mine are V2 and I've left both in auto mode since August with no issues.

I have 3 of the older MFW's and have no issues with amps or anything else. I'm home all the time so my system is on for 14 to 16 hours per day what with music, tv, or moves. amps are doing just fine.

Bill

It's good to see people have good experience with theirs and even though my 2nd MFW has been an issue MFW # 1 has been great. I can't use auto shutoff but otherwise it has been fine and sounds fantastic.

Ran some more tests by turning the gain knob on the sub.
And so far the amp and driver look fine to me.
The amp did run cool for the entire 30 minutes I ran the tests.
Test tones were mostly, 40HZ, 30HZ and 20HZ.
No thumping or any other strange noises either from the cabinet or the driver surround.
This is at 31HZ (gain knob on mfw at 2 'o clock, AVR Sub level at +8, no other speakers connected):

I have use an X10 module to turn off my MFW-15. It makes a thunking noise turning off which none of my other subs do/did but I don't want to pay my electric company $22-24 dollars a year to use my sub as a space heater (yes this is what it would cost at 11.5 cents per/KWH). I have had the MFW-15 since January I swapped the first amp because it has transformer hum the second is much better. No problems so far caused by my hard powering off (transformer hum was there from the get go). I don't think you will get good data one way or the other. I'd just pick your bias/poison on whether to turn off or not.

You're running much hotter than I would at +8 on the AVR, for my v2 MFW I run at -4 in the AVR which nets 75db on the meter at the listening position. What does the meter read using the setup test tone in the AVR for the subwoofer when running this way? Typically people set it for between 70 and 80db.

I'm not saying you're running it wrong, it may need this much to get to 75db on the meter at the listening position.

Whats your volume setting on your AVR? More importantly what are you reading at 40Hz? 5-7db hotter?

My Feb 2010-purchased B-stock MFW w/ v2 amp is kept in the AUTO mode, no burps when it powers on to green light (that I can hear), or on power off to red light (though I'm usually out of the room by that time anyways). It's plugged into it's own Panamax M5410 Pro, but will be using a Panamax M2Sub as soon as I take 2 minutes to do so to free up some floor space. I have no idea if the v2 amp is even warm in standby, but will check later tonight.

So far, my v2 amp and MFW have worked just fine since it was delivered , and have only experienced a few moments where it was a bit overdriven by some very challenging LFE passages at higher-than-normal-listening volumes.

Sorry to hear about the inconsistent v3 amp performance. If anything, maybe another reason to consider the Turbo upgrade when it's available. That, or part out your crippled MFW, then chop up the cabinet for firewood when the temps start dropping this fall...

If I knew I could sell my MFW for a decent price, I'd probably just buy a PB13-Ultra and be done with sub upgrades.

Ah, just another tattered page in the continuing MFW novella...too bad, since I have seem to have a pretty darn good working one.

Right, I only did this for testing. AVR is usually at +1 or less.


I believe it is 75 but I'll check it again.

More like 3db I think but I will write it down for reference.

Right, this was to test max output only. Not for normal listening.

If everybody in this thread who was not happy had purchased an SVS, Hsu, Epik, or what have you, no one would have had any problems to begin with and this thread would not exist. You know, when I was 15 my friend back in California got himself scammed by the white van. I didn't know about it either and if it were me, I would have gotten ripped off. I was lucky it was him and not me, but it was a valuable lesson learned for both of us.

I was just thinking posting actual test results would be better then posting 2nd hand information. But you're right, he has subs to sell.

Easier said then done. In the beginning "this" sub out performed "those" subs and many purchased "this" sub before they noticed the white van leaving the parking lot.

I adjusted my graph units to be similar with what was used here. The graphs are similar to my eyes15-20db roll off under 20, both have the ~30 dip. The V2/V3 do have some midrange swell not on the old graph though.




Also a couple afterthoughts:

• Check your phase with the new amps carefully. In other words if the V2s worked great at 180 that doesnt mean the new amps will. They must be set all over again from scratch.
• Some of the roll off seen in my graph approaching 80Hz might be the AVR crossing over since i set my crossover to 80Hz. I should have set it to like 200Hz or something to rule it out.
• Still listening for final verdict on this one.

Nick, you got that response "in-room"? I believe Craig's measurements were ground plane. Interesting.

Yeah, just put the SPL meter about 10-12" from the port laid on the floor.

KH- check your phase, I recall you saying you couldn't hear the new amp when it was playing with the V2, maybe they are out of phase?

Last night I was playing with integrating mine together and was getting poor response. I had transposed the phase setting off my old V2 amp to the new V3(wrong I know). Turns out they were out of phase horribly, reset the phase on the new V3 and netted 10db increase with the two phase matched. I know this is not earth shattering news, and its fundamental when integrating two subs, but seeing the cancellation of two out of phase warranted at least a mention.

NicksHitachi,

I set mine up in a 2 channel rig so the AVR would be completely removed from the equation. Straight from Mac Pro, to mixer to 2 channel amp using the following.

Last night I could only perform listening tests since I worked until midnight.

Running the same song on each config the only adjustments I could make were the volume on the Mac Pro, gain settings on the mixer and gain settings on the plate amp.

V2 plate amp set to 11am, Mac Pro volume set to 50% and mixer channel gain set to 75%, main volume on mixer at 40% netted 100db.

V3 gain set 100% netted 88db, another unscientific test I know but there it is. I am copying my test tones to my Mac Pro and running better tests when I have some time.

I'm in the JP Morgan Chase (I hate the company, but like the event ) corporate challenge tomorrow and Friday going to a Cubs game so not going to have time until this weekend.

I have no doubt the V3 that NicksHitachi got works as designed, unfortunately it looks like the one I got and a few others received doesn't. I am going to prove it as best as I can however I think the basic test conducted so far proves without a doubt my V3 amp is weak compared to the V2.


My ears are very sensitive to phase, this was the first thing I checked for, Kyle mentioned it as well. One thing very noticable between the two is how the driver is pushed, my V3 at max and being pushed hard doesn't move the driver much, the V2 is very capable of blowing the driver out of the box if pushed too hard.

KH- when you pull out the V3 amp, look to see if there was a "tested OK" sticker on the back side of the amp plate. I saw mine somewhere close to the transformer I think. Not that it means anything, just curious.

If memory serves, mine does not have this sticker but I'll verify tonight.