How to safely determine if amp is damaged? (1 Viewer)

[AndrewKC]

I recently experienced a woofer meltdown in one of my tower speakers. This set up was a passively biamped one--that is I had my receiver powering the mids and tweeter, and a subwoofer amp powering the woofer. One day I smelled burning plastic, and then discovered my amp was sizzling hot and the woofer was destroyed.

So now I'm getting a new woofer, and I'm quite hesistant to re-connect the amp to the woofer because I don't know if it is what caused the woofer damage, or if it was a bad woofer to begin with. Does anyone know of a safe way to test to see if the amp is okay to use?

 

[Craig Robertson]

have it checked out by a technician.

 

[Chu Gai]

And what was that subwoofer amp that you were using?

 

[AndrewKC]

The amp in question is an NHT SA-2. I'm not sure if I want to send it in to their service center because it'll probably cost 25-30 bucks each way for shipping, and then they'll charge something like 20 bucks just to look at it. So if nothing is wrong with it, it will have cost me 75-80 dollars to find that out. The thing cost me 300 or so originally.

 

[Jason.Soko]

For $300 I would just throw it out and buy a new amplifier. That isn't even worth the shipping and servicing fee.

 

[Chu Gai]

I take it you were using NHT speakers and following one of the plans outlined in the manual for the SA-2. I'd begin by reviewing if I'd done the connections properly to begin with and that I hadn't maxed out that amp in any way. You might want to contact NHT for guidance on your question. Perhaps if this is still under warranty you may be pleasanty surprised at the costs.

 

[Craig Robertson]

even if it isn't under warranty, they may suprise you.

 

[AndrewKC]

Chu, I'm pretty sure I didn't do anything wrong with the settings, because I've had the speakers and amps set up in the same manner for over a year now. Unfortunately the warranty period is a year, and I'm definitely past that point. Craig, have you had a good experience with the NHT people? I had to call them to replace my woofer, and they didn't ask me if my speakers were still under warranty. I didn't have the receipt anymore, so I wasn't eligible for warranty replacement (it cost 145 bucks!). I'll call them later this week when I get the chance, I guess.

 

[JohnSer]

Check all fuses within the amp, make sure none of the rail fuses are blown (if it has them). Power it on and use some cheap disposable speaker first. Any 4-8 ohm speaker you have laying around. An old car, boombox, or other cheap speaker should do. Just run the volume enough that you can tell the amp is functioning OK. This should be enough of a test to save your $150 NHT.

JohnS