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mak99
Mark_Seaton wrote:
Murrel wrote:
I would think that if anything the UFW is harder to drive than the MFW driver as the UFW driver is very stiff excursion wise

Murrel


The suspension has little to do with how hard a speaker is to drive.  The impedance curve and the spectral content of the signal used matters much more...

Mark - thanks for the educated response, especially for someone like me that will always ask for help when I'm in unfamiliar territory.

Murrell - No offense, but you might want to do some add'l research (maybe even PM Mark and/or Kevin for their thoughts?) before you respond with what could be interpreted as your "best guess"?  Your response did seem plausible to me, but I guess a well-versed, sounds-reasonable-and-educated response-but-incorrect-response is still incorrect...  Good luck with your endeavors to sell/fix all those amps...
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Timeless_Tech
I'm glad Mark made the distinction between the various types of hum that have been reported. My amps have thus far all died of that 3rd type. Way back in the bad old days of "brute force" non-switching power supplies and discrete components mounted on printed circuit boards, such newfound hum would (at least initially) have you looking for a bad capacitor, maybe a leaking electrolytic letting 60 cycles from the power supply play havoc with the signal before reaching the amplifier.

As for the current hum, if it's induced thermally, the change is not diminished by cooling. It's there immediately the next time the unit has power applied, no matter how long powered completely off (not just between so-called Standby and On).

I've been away from component level of troubleshooting for way too long, but if someone has an interest in following the traces and the software to generate one, I for one would find it interesting to see the schematic(s) of the various boards and how the amps evolved over time. I'm pretty certain schematics would be a valued part of the MFW-15 archives.

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Array

You can sign me up for two.  One of the two I have failed recently, and the other has always had a tiny bit of transformer hum.  And I guess the one that still works is on borrowed time now.  So, I'm in for a pair.

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nottaway
Will the new amps be 2-prong or 3-prong?

I don't know what it is about this sub, but I have had to battle ground loop hums with V2 and V3 amps because of the ground plug. 

However the VTF3-MK3 they replaced never hummed a bit in the same location.......
AKA NicksHitachi
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sandbagger
nottaway wrote:
Will the new amps be 2-prong or 3-prong?

I don't know what it is about this sub, but I have had to battle ground loop hums with V2 and V3 amps because of the ground plug. 

However the VTF3-MK3 they replaced never hummed a bit in the same location.......


At this point I cant say with any certainty but.... my guess would be that it will have the standard IEC C14 connector on the back to take the standard 3 prong power cord.
Kevin
Motor City Custom Audio
http://motorcitycustomaudio.com/
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Irishlord82

One of my two MFW-15's has developed a buzzing sound and after checking all the connections, seems to be the amplifier. I am interested in a new amp before I destroy this sucker and place it in the trash. My purchase was in May, 2008 so I think I got the "good" driver. How do I confirm this? Thanks.

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Carp
Thanks Mark and Kevin for working on this for all of us that feel taken.  I'm anxiously waiting for the new and improved "Right" amp availability.  Mine's been dead now for 2 months and missing the boom

Thanks again

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nanok

Mark_Seaton wrote:
Murrel wrote:
I would think that if anything the UFW is harder to drive than the MFW driver as the UFW driver is very stiff excursion wise

Murrel


The suspension has little to do with how hard a speaker is to drive.  The impedance curve and the spectral content of the signal used matters much more.  From an amplifier's perspective, the UFW-12 is a very easy load to drive, especially between 25-50Hz.  With most of these types of amps, at high output the amps are happier as more of the power gets dissipated across the load and not the output devices.   It would be more useful to test in an MFW-15 box at moderate level as the small chamber is what likely highlighted this weakness in the amps.

There were a few sources of hum which had been noted over time.  One was related to the umbilical up to the control panel and its proximity/orientation to the power transformer (a few ways to reduce this).  Another was a matter of grounding and ground loop issues, and the third was only loosely documented, but seemed to be a progressive problem as the amp died and was likely related to some of the parts with poor tolerance combined with sensitivity to heat. 

I am still pursuing a few promising options from different suppliers to insure we'll have a solution sooner than later.

The highlighted portion seems to have just bitten me in the arse. I've been running mine for ~1 year, and all has been fine. I started notice a slight hum (not the typical ground loop sub hum) the other evening. It wasn't that lound and was easily browned out by the rest of the system. However, I didn't feel confortable leaving it plugged in with the problem if I wasn't going to be there, so I discconecyted it from the wall before I went to work. When I remembered it was unplugged last night, I plugged it in in front of my wife, and the hum was back, but even louder. Watching TV last night I came to these forums checking onthe upgrade, and found there are lots of people like me, and now AV123 is gone.
Perhaps I will get on the list for the upgrade, but might pull the trigger on this if it happens sooner than my number is called.
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paw
nanok

Contact Murrel. He's able to repair the bad components.
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Moikey
I was just recently pointed to this as an option and am anxiously awaiting the final product. I have two MFW15s. I had AV123 replace one amp almost immediately after purchasing and now the other needs replacement. I am sure the first one that was replaced will die soon.  I am so glad there is a good economical option moving forward, thank you Seaton!  The turbo option is very tempting as well.  Maybe if there was a poor man's turbo
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boober
Apparently there is a poorman's on the horizon. Which is good because we're obviously not rich if we bought MFW's... Still patiently waiting for updates on this from Mark and Kevin.
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jparkhur
As i find my new v3 amps developing issues, i would like to wait and get two new replacement amps.  Q: could i just hook them to a triad 500 dsp and run them fine?  What is the ohm on the driver?  How long till we see amps from Motor City????
THanks
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Timeless_Tech
jparkhur wrote:
As i find my new v3 amps developing issues, i would like to wait and get two new replacement amps.  Q: could i just hook them to a triad 500 dsp and run them fine?  What is the ohm on the driver?  How long till we see amps from Motor City????
THanks


The v3 amps now, too? You have more than 1 it appears. Are they exhibiting the same symptoms? Please tell us more . . .
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jparkhur
Morning,

I have two of the v3 amp versions.  Yes, the unusable controls at top.  I have tried everything.  I have removed all electronics, changed RCA's, moved outlets, used jumpers etc.  One of my subs has a constant hum when only plugged in to power, no rca attached.  The other has yet to have this issue, but i am hedging my bets.  If i have to fix one, i'll have to fix both to have similar sound.  I am currently using a ACI Meastro  XL that Mike Dzurko gave me and the two MFW 15's.  So I have no issues, i just want to replace the two amps with either drop ins, or and external 500 or 1000 watt amp to use with both drivers.  I am not sure the second is going to work due to ohm load.    Time line on amps???  

FYI:  I have taken amp apart and moved coil some, checked all connections too.  Nothing seems to work.
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boober
Out of boredom 1 day, I hooked up a Samson S1000 stereo amp to 1 of my MFW's and ran it like that for about an hour and it did fine. The Samson was giving it basically 500 watts at 4ohm. I didn't push it that hard out of fear, but it did work ok for as long as I had it that way. I'm hoping that maybe 1 of the options Kevin and Mark come up with is an amp that can be hooked up externally like my Samson 2 channel amp. I don't care either way if I use a plate amp. It's irrelevant to me, I'm just looking for the cheapest method which would be a good 2 channel amp. Since I have 4 MFW's, the CHEAPER the BETTER
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sandbagger
boober wrote:
Out of boredom 1 day, I hooked up a Samson S1000 stereo amp to 1 of my MFW's and ran it like that for about an hour and it did fine. The Samson was giving it basically 500 watts at 4ohm. I didn't push it that hard out of fear, but it did work ok for as long as I had it that way. I'm hoping that maybe 1 of the options Kevin and Mark come up with is an amp that can be hooked up externally like my Samson 2 channel amp. I don't care either way if I use a plate amp. It's irrelevant to me, I'm just looking for the cheapest method which would be a good 2 channel amp. Since I have 4 MFW's, the CHEAPER the BETTER


I thought you were doing 4 Turbos??
Kevin
Motor City Custom Audio
http://motorcitycustomaudio.com/
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Worlok
Put me down for 1.  I am in the same boat as many others who have posted.  Sent my amp in for repair at the end of July and never received a replacement or the original humming unit back.  Now I have an amp-less cabinet taking up floor space in my living room, hoping to find a way to bring it back to life.



Rod
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boober
sandbagger wrote:
boober wrote:
Out of boredom 1 day, I hooked up a Samson S1000 stereo amp to 1 of my MFW's and ran it like that for about an hour and it did fine. The Samson was giving it basically 500 watts at 4ohm. I didn't push it that hard out of fear, but it did work ok for as long as I had it that way. I'm hoping that maybe 1 of the options Kevin and Mark come up with is an amp that can be hooked up externally like my Samson 2 channel amp. I don't care either way if I use a plate amp. It's irrelevant to me, I'm just looking for the cheapest method which would be a good 2 channel amp. Since I have 4 MFW's, the CHEAPER the BETTER


I thought you were doing 4 Turbos??


I had been considering maybe doing 1 or 2 Turbo's. And maybe selling 2 of my MFW's to help pay for the 2. But then av123 went out of business, and no one seems to be having that much luck selling these things now for a halfway decent price. I dunno what the hell I'm gonna do, just waiting to see what you and Mark finally come up with before hopefully being able to make up my mind.
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ASAL
You could count me in for one of these.  I'm on the current turbo list but this might be a little more economically sound as long as they become available.
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synergytheory
On my third MFW-15 amp that has blown. Count me in for a replacement also.
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rfglock

any chance the new amp will have a balanced input?

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sandbagger
As of right now that is a good question.

There is a balanced input on one of several options we are looking at.  I dont know if it will the amp we go with or not yet.

So to answer your question.... its a big MAYBE

rfglock wrote:

any chance the new amp will have a balanced input?

Kevin
Motor City Custom Audio
http://motorcitycustomaudio.com/
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rfglock
Thanks. Not a deal killer but would be nice
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poormonkey
Well, one of my MFW-15 amp's now has the hum again.  I already replaced it about a year ago via warranty and now the replacement one is going.

I can dream about the turbo upgrade, but right now it isn't an option for me.

The question I have is their anyone out there that can isolate and repair the amp?   I have the original one that went bad in my closet, and now I have the second bad one in the sub.   If anyone has any info on someone who is qualified to repair them, please let me know.

Thanks.....
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boober
poormonkey wrote:

The question I have is their anyone out there that can isolate and repair the amp?   I have the original one that went bad in my closet, and now I have the second bad one in the sub.   If anyone has any info on someone who is qualified to repair them, please let me know.

Thanks.....


http://av123info.us
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