Speaker Protection Circuit

In the Gobo instructions there is mention of a speaker proteciton circuit that can be added to the Gobo case or externally.  Do you have any advice on where one can purchase a speaker protection circuit to build or simiply to purchase on outright.  If purchasing outright, how does it connect to the Gobo amp?  Any data for ressearch would be very helpful.

I would also like to add speaker protection (for DC protection and to prevent those thumps on turn on/off). There are many kits on ebay, I am looking at one that requires 12-20 VDC. Can I use the output from the Gobo pwr board? Mine is the 240V version with the Antek transformer and puts out 16V at the terminals. If I piggyback this extra kit board off the amp pwr board wold it degrade/affect the audio any?

 

IMHO the bump/pop doesn't really hurt the speaker at such a low power level, but I won't contradict you if you think you need it. The pop is caused by an imbalance in the positive and negative power rails when you first turn the amp on or off. One or the other power filter cap charges or drains faster than the other. So, taking power off one rail and not the other could, theoritically, make the problem worse. 
Given that there's no output cap, I guess you could have a fault that puts DC on the output. but, my philosophy is that everything between the instrument (or vocal chords) and your ear adds distortion.
Bottom line--there's no obvious technical reason why you can't take the power off one or the other rail. Let us know if you try this.
 

Thanks for the info Ken,
The speaker thump/pop is really just an annoyance for me but when I started researching it I found out about the effects of DC offset on a speaker and coincidently am currently replacing a driver in our polks due to this very thing caused by the old amp. So I thought I would add  a circuit to the gobo for piece of mind.
 
I agree with you about less "stuff" between source and speakers is better but from what I have read these protection circuits are pretty much a short (through the relay contacts) when they are active so It shouldn't affect audio quality in anyway. I'm no expert though and stand to be corrected on that.
 
There is a velleman kit out there that has it's own transformer on board so that would go in a standalone box, but there are plenty of others that dont have onboard pwr supply so I thought if I could tap into the gobos' then I could shoehorn the board into the same case, saving on extra pwr and audio interconnects.
 
I'll let you know what I end up with. Be nice if boxedkitamps had a protection circuit kit?..... :-)