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NEW MFW-15 amps (May 2010) *pics* - Page 77

post #2281 of 2590
Quote:
Originally Posted by Mr.Metal View Post

I haven't been on this forum for a while, but today, my MFW-15 amp started humming like crazy. Now, it always had a little hum that wasn't audible as soon as the audio came on, but now it's bad. Very bad. Sounds like the common issue.

I bought my sub in August 2008, so I'm not sure what amp version I have. I'm not really good with small electronics, so replacing capacitors seems like a bit of a problem. Reading around, I see that replacement amps were offered, but are no longer in productions.

So... what are my options for fixing or replacing my humming amp now?

Thank you in advance.

Mr. Metal

Check out the link in my sig. Your sub should be a V2 and the hum fix should take care of your problem.


I'm here to help so don't hesitate to contact me.

Murrel
post #2282 of 2590
I'm moving and I need to get a smaller sub. What's the used market for MFW-15s these days? Can't imagine they go for much on the bay with shipping, etc.
post #2283 of 2590
Quote:
Originally Posted by Dirac View Post

I'm moving and I need to get a smaller sub. What's the used market for MFW-15s these days? Can't imagine they go for much on the bay with shipping, etc.

Dirac

Where are you located? What color is the cabinet and do you know what version amp you have?

Murrel
post #2284 of 2590
Quote:
Originally Posted by Dirac View Post

I'm moving and I need to get a smaller sub. What's the used market for MFW-15s these days? Can't imagine they go for much on the bay with shipping, etc.

I've been wondering the same as I've thought about getting rid of mine so I can go duals. Luckily, I have a V3 amp, which I'd think would make it way more marketable.
post #2285 of 2590
Quote:
Originally Posted by Dirac View Post

I'm moving and I need to get a smaller sub. What's the used market for MFW-15s these days? Can't imagine they go for much on the bay with shipping, etc.

I'd say about $100.00, shipped to Lincoln, Ne-->

HH
post #2286 of 2590
If I was you Dirac I would try to find someone local that is interested in it. I can say that if you were local to me I would be interested even knowing my MFW-15 is still down because of the dreaded hum. Hopefully mine will be fixed soon. I would love to have duals just to have them. lol
post #2287 of 2590
It's piano black with a v2 (professionally cap-fixed by a microelectronics builder) and there's no way I'm paying to ship it to Omaha! Would love to run double subs at some point and it would obviously be nice to have them match, but I can't hang on to this one and try to find a second one (several?) years down the road.

I'm in the Dayton OH area.
post #2288 of 2590
Quote:
Originally Posted by Dirac View Post

there's no way I'm paying to ship it to Omaha!

Good,,,I live down the road in Lincoln, So, We have a Deal??-->JK

GLWS

HH
post #2289 of 2590
Oops, got my wires crossed! Haha Lincoln's even farther though.

Dayton's a bit of a tough market for something like this--a bit small and not much going for it for AV enthusiasts IME. Cincinnati, Columbus and Indy might be better, though.
post #2290 of 2590
I stopped by Radio Shack this morning and picked up a 45 watt desoldering iron. I tried using my existing 30 watt iron again and it just isn't working. Maybe my current iron is defective which would explain a lot. The only other time I had an issue like this soldering was when I tried using "lead free solder" to attach speaker wire to banana tips. The lead free solder would not liquify at all. I gave up on the lead free solder and picked up some regular solder which worked perfectly.

If I remember correctly lead free solder has a much higher melting point. Which if my existing soldering iron is defective would explain why I'm having a problem.
post #2291 of 2590
The new soldering iron did the trick! I got it all back together and it seems to be working well. There is a very slight hum if I put my ear within @6 inches of the driver. Over a foot away I can't hear it at all. I listened to a few songs and it sounded great. Changing the caps appears to have fixed the problem. Thanks Murrel!

Now that it is working properly I can hold out upgrading for a bit. I don't need much more than a single MFW15 because my main speakers each have two 8" self powered woofers. They are rated down to 20hz but I cross them at 40hz, since that is the lowest I can set it before full range. They work well together overall. I will look into the turbo upgrade if it ever becomes available.

So now that it is working should I leave the amp plugged in and on auto or on? Should I unplugg it when not in use? If I remember correctly most of the amps are damaged when first turning on. That leads me to believe that leaving it in the on position is the best answer.
post #2292 of 2590
Quote:
Originally Posted by beekermartin View Post

The new soldering iron did the trick! I got it all back together and it seems to be working well. There is a very slight hum if I put my ear within @6 inches of the driver. Over a foot away I can't hear it at all. I listened to a few songs and it sounded great. Changing the caps appears to have fixed the problem. Thanks Murrel!

Now that it is working properly I can hold out upgrading for a bit. I don't need much more than a single MFW15 because my main speakers each have two 8" self powered woofers. They are rated down to 20hz but I cross them at 40hz, since that is the lowest I can set it before full range. They work well together overall. I will look into the turbo upgrade if it ever becomes available.

So now that it is working should I leave the amp plugged in and on auto or on? Should I unplugg it when not in use? If I remember correctly most of the amps are damaged when first turning on. That leads me to believe that leaving it in the on position is the best answer.

Hi Beeker,

Did you make sure to route the low level wires waaaay away from the transformer? If the ribbon/grey wires that lead up to the controller are close tor the transformer some transfirmer humm can contaminate the signal path.....

Also leave it plugged in, i leave mine in auto but many leave it on 24/7.
post #2293 of 2590
Quote:
Originally Posted by NicksHitachi View Post

Hi Beeker,

Did you make sure to route the low level wires waaaay away from the transformer? If the ribbon/grey wires that lead up to the controller are close tor the transformer some transfirmer humm can contaminate the signal path.....

Also leave it plugged in, i leave mine in auto but many leave it on 24/7.

Beeker,

Nick is correct Leave it on and just don"t worry about it

Murrel
post #2294 of 2590
Quote:
Originally Posted by NicksHitachi View Post

Hi Beeker,

Did you make sure to route the low level wires waaaay away from the transformer? If the ribbon/grey wires that lead up to the controller are close tor the transformer some transfirmer humm can contaminate the signal path.....

Also leave it plugged in, i leave mine in auto but many leave it on 24/7.

I am pretty sure I did. I remember when I first got the MFW-15 I had to do that. I zip tied them out of the way back then and that did help with the hum. When I put it back together last night I know I made sure the cables stayed to the left. If I have time tonight I will take it apart and double check. Does it matter where the driver wires are routed?
post #2295 of 2590
Quote:
Originally Posted by beekermartin View Post

I am pretty sure I did. I remember when I first got the MFW-15 I had to do that. I zip tied them out of the way back then and that did help with the hum. When I put it back together last night I know I made sure the cables stayed to the left. If I have time tonight I will take it apart and double check. Does it matter where the driver wires are routed?

I brought mine all the way around the edge of the power supply board far left from back and ran the high level wires(driver leads) to the right between the boards and transformer.

Make sure to keep all wires away from the high level inputs too(binding posts on back).... I even unplugged them on the amps I wasn't using them to ensure nothing got into that signal path either.... Don't know if that helped or not.

All of my wiring harnesses are also wrapped in weather stripping to help keep those wires isolated. I used camper shell weather stripping foam from lowes and wrapped the harnesses all the way to top. You have to pull it all the way out to do this.

Oh, and make sure the gain on the amp isn't up past 9-10oclock, turn it up on the AVR(controller) and turn the amp down. The V2 gain stage is pretty noisy.
post #2296 of 2590
I finally got around to some late night jamming and my MFW-15, with the caps replaced, handled it without issue.

Thanks again Murell! Please PM me you paypal account I would like to send you a buck or two for your efforts! I once asked a doctor for some free advice and he told me to book an appointment. lol just saying.....
post #2297 of 2590
I have two off these subs but not sure which version. I use cheater plugs to avoid a humming sound, but did so with other subs in the same room. I'm guessing its a ground loop.
If it were the amps would I get the humming even with the cheater plugs?
post #2298 of 2590
If cheater plugs get rid of the hum, its not the caps and is just a ground loop issue.

Quote:
Originally Posted by datguy85 View Post

I have two off these subs but not sure which version. I use cheater plugs to avoid a humming sound, but did so with other subs in the same room. I'm guessing its a ground loop.
If it were the amps would I get the humming even with the cheater plugs?
post #2299 of 2590
Quote:
Originally Posted by beekermartin View Post

I finally got around to some late night jamming and my MFW-15, with the caps replaced, handled it without issue.

Thanks again Murell! Please PM me you paypal account I would like to send you a buck or two for your efforts! I once asked a doctor for some free advice and he told me to book an appointment. lol just saying.....

beekermartin,

You are welcome!

Glad the hum fix worked for you.

Have a great weekend
Murrel
post #2300 of 2590
Quote:
Originally Posted by datguy85 View Post

I have two off these subs but not sure which version. I use cheater plugs to avoid a humming sound, but did so with other subs in the same room. I'm guessing its a ground loop.
If it were the amps would I get the humming even with the cheater plugs?

If you remove all input cables from the sub and it still hums then it is a problem with the sub's amp. If it only hums when you have your input cables attached to the sub.....then you have a ground loop.


If you need help or have questions just contact me.
Murrel
simplysound@msn.com
post #2301 of 2590
One of the subs has a very slight hum and a domed capacitor...which is also the one that bottoms out before the other. Could the cap fix take care of the bottoming out, or may I need a new driver?

Has anyone in the Indianapolis area taken there amp someplace for the fix? I'm not brave enough to do this one...

Thanks
post #2302 of 2590
Quote:
Originally Posted by datguy85 View Post

One of the subs has a very slight hum and a domed capacitor...which is also the one that bottoms out before the other. Could the cap fix take care of the bottoming out, or may I need a new driver?

Has anyone in the Indianapolis area taken there amp someplace for the fix? I'm not brave enough to do this one...

Thanks

Do the hum fix it will solve the hum. It will not fix the bottoming driver. You will just need to turn down the gain on that one. I have had 4 MFW's one of them would bottom out at what seemed like the same setting as the other three. It's just how it goes with the V1 and V2 amps. Sorry.

If you need help I am available.

Murrel
post #2303 of 2590
Thanks for your help.

Is there a comparable driver under $100 that would be worth trying? I can't run them much in this house, but we plan on moving in a few years. Just want to keep my options open.
post #2304 of 2590
Quote:
Originally Posted by datguy85 View Post

Thanks for your help.

Is there a comparable driver under $100 that would be worth trying? I can't run them much in this house, but we plan on moving in a few years. Just want to keep my options open.


This is as cheap as they get, and a drop in replacement. They are going to be on sale for a couple more days.

http://www.parts-express.com/pe/show...number=295-190
post #2305 of 2590
Just a "heads up" to those looking to sell their MFW15. You need to take into consideration the WEIGHT AND the overall DIMENSIONS of the original box if you are planning on shipping it. You will also find out that the size of the original shipping box puts you in a whole new pricing structure for fedex and ups. It is considered an "OS" size package and as such is EXTREMELY expensive to ship via common carrier. Do not go by weight alone...
post #2306 of 2590
Quote:
Originally Posted by streamerlover View Post

Just a "heads up" to those looking to sell their MFW15. You need to take into consideration the WEIGHT AND the overall DIMENSIONS of the original box if you are planning on shipping it. You will also find out that the size of the original shipping box puts you in a whole new pricing structure for fedex and ups. It is considered an "OS" size package and as such is EXTREMELY expensive to ship via common carrier. Do not go by weight alone...

Pro tip: Check into Greyhound. If you can get it to a Greyhound station and your receiver can also get to a Greyhound station their rates for transporting larger & heavier items is FAR better than the big name shippers. Also, FedEx Ground (different than FedEx) tends to be the least expensive for large/heavy objects than the other big name competition. I do lots of shipping of items all sizes so that's my tip of the day.
post #2307 of 2590
Quote:
Originally Posted by streamerlover View Post

Just a "heads up" to those looking to sell their MFW15. You need to take into consideration the WEIGHT AND the overall DIMENSIONS of the original box if you are planning on shipping it. You will also find out that the size of the original shipping box puts you in a whole new pricing structure for fedex and ups. It is considered an "OS" size package and as such is EXTREMELY expensive to ship via common carrier. Do not go by weight alone...

I actually shipped an MFW across the country via UPS for < $50 using our work UPS account. I was surprised how cheap it was.
post #2308 of 2590
Quote:
Originally Posted by bmrowe View Post

I actually shipped an MFW across the country via UPS for < $50 using our work UPS account. I was surprised how cheap it was.

For some perspective to those of us lacking a work account:
To ship a pair of small bookshelf speakers (Ascend HTM-200s) from AZ to AR was $30 for me with UPS.
post #2309 of 2590
Quote:
Originally Posted by bmrowe View Post


i actually shipped an mfw across the country via ups for < $50 using our work ups account. I was surprised how cheap it was.

bs
post #2310 of 2590
Looks like a had a loose red wire connected to the driver...I reconnected it and the clipping and the humming quit!
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