Mysterious sound from Sunfire - Amp or Driver Problem? - AVS Forum
Subwoofers, Bass, and Transducers > Mysterious sound from Sunfire - Amp or Driver Problem?
ksdehoff's Avatar ksdehoff 10:40 AM 01-09-2013

I have an old 12" Sunfire True Signature Subwoofer from 2002. Sunfire will not repair this because it is too old so I am looking to repair this myself if it is salvagable. I have a mysterious problem that I'm hoping someone on the forum will have experienced before that can help point me to the problem component. The problem is that I have an 80 hz harmonic at lower volume levels.

My example source is the initial track of Dark Side of the moon. The heart beat runs at 40-60 hz but I also get a big pop at 80 hz at every beat. The magnitude of the pop goes down as the input signal increases so it is pretty intermittent overall - but very annoying.

So any thoughts on whether the amp may be doing this or whether I have a driver gone bad?

ksdehoff's Avatar ksdehoff 07:14 AM 02-05-2014
As an update to this, I was able to do the circuit board repair based on other information on the web - several capacitors had gone bad. To avoid the problem in the future I had to upgrade this to dual PSA XV15s and have retired the sunfire to my PC. Anyone with some patience should be able to complete this repair the same way I did
BeeMan458's Avatar BeeMan458 08:46 AM 02-05-2014
Congratulations on your success and new purchase. I guess if one has to suffer the indignities of life, doing so with a pair of XV15s goes a long way in distracting one from everything else.

SmittyJS's Avatar SmittyJS 10:36 AM 02-05-2014
Originally Posted by ksdehoff View Post

I was able to do the circuit board repair based on other information on the web

Care to post those sources?

I'm bookmarking repair shops and DIY articles in case my Sunfires ever go bad.
ksdehoff's Avatar ksdehoff 10:43 AM 02-05-2014
The technique was posted here:

There was a workaround suggested to short two pins on an IC to avoid the power save feature - I do not recommend this as it appears to have made my sub perform worse.

I went through the capacitors listed with a capacitance meter and found several bad caps - got them from Mouser and I've been up and running ever since. I fortunately did not have issues with any other components on the board
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