Spectra 11, scratchy sound

Read more on the Acoustat Spectra 11 in our home audio section

Matt Herko2007-07-10 00:13

I have a pair of Spectra 11\'s,one of which recently started making the music sound garbled & scratchy when playing. I open up the circuit panel portion, and found that the resistor nearest the 2 ballast resistors is burnt. The one next to it looks like it might be starting to cook too. (this is on the right of the burnt resistor, the smallest one on the board) The circuit panel itself is a bit browned where the burnt resistor is as well. Any ideas what went wrong, and if so where/how to replace it?

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Andy Szabo2007-08-01 23:50

It is not uncommon for the resistors in the Spectra 11 interface to get very hot, sometimes to the extent of getting quite \'toasted\'. If you play a lot of loud music, you can expect this to happen. These resistors are easliy replaced, and if you use better-quality, metal-bodied resistors, they can be mounted on the metal chassis (to act as a heatsink) and connected to the board with short lengths of wire. However, I\'m not sure the burnt resistors are causing the \'garbled and scratchy\' sound. Resistors don\'t usually fail in that manner. You may have some high-voltage arcing on the board or in the transformer. Go ahead and replace the resistors first, and see if that solves your problem. See my piece called \"Ted Nugent vs Spectra 1100\" located under \"Spectra 1100, Refurbishing\" to see how I did a similar modification to the Spectra 1100. Look for any signs of arcing (i.e. black marks) on the components and wiring to see if you have a greater problem. Check too, for any loose connections at the speaker wire, wall-transformer plug, woofer box to interface, and panel-to-interface connections. Write again if you still have the problem or need further advice.

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