Mackie SRS1500 Powered Sub Issue

[Erich031667]

OK, I have a Mackie SRS1500 powered sub that has no noise at all. I am trying to use it in the "balanced full-range" mode. I made an unbalanced XLR to 1/4" cable as the board we are using has no balanced outs. I used the typical "Pin 2, hot ~ Pin 1 & 3 ground" as I have always done for low Z mic config. Have I screwed this up? It didn't work when I first tried it, but it powers on. Any help would be appreciated. Thanks, Erich!!!!

[Greg C.]

Your cabling sounds fine. It's probably a blown amp module or a blown driver.

[ijpengelly]

Is there any kind of pop or thump when you turn the sub on? Is the green and blue power lights coming on? If you are getting power and no noise it could be a failed driver or the amp module may have failed. You'll need to strip the amp off the back and check the internal fuses and driver impedance as a first check.

I've recently repaired the newer version, which has the same amp in it, so hopefully I can talk you through any further checks.

[Greg C.]

I've recently repaired the newer version, which has the same amp in it, so hopefully I can talk you through any further checks.

Couldn't be that new if it has the same amp module. All the Mackie stuff for a while now has been using class D amplification. It sounds like you're referring to the SWA line which has been discontinued for some time.

[ijpengelly]

Oh and if the 8Amp fuse that is on the right hand side of the amp board half way up has blown, be very careful the main power capacitors will still be charged and could be at a potential of up to 120VDC!!!! 

If this is the case, you'll need a light bulb (or highpower resistor with a value of circa 50 Ohms) with test leads to discharge them.

Take care and if you don't feel confident handling such a task take it to a trained professional. Its really not worth the risk of electrocution. 

[ijpengelly]

I didn't say it was new, I said it was newer 

It was indeed the SWA1501 that I had in and it was a hybrid class G. The schematics are widely available.

[ijpengelly]

Did you have any luck with it Erich?