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Discussion Starter #1
I would like to experiment with tri-amping but leery of running my tweeters naked. Opinions and rationale are all over the map on best approach:

DAC>DBX Speaker Manager>Amps(3)>Speakers (Crossover bypassed)

1. Fuse
2. Bulb
3. Capacitor
4. Polyswitch
5. Paralleled zener diodes

Obviously sound quality is important but I am not “obsessive” and, at this point in experimenting at least, hoping to avoid complex circuitry. I am leaning towards Polyswitch as best compromise.

Opinions/Suggestions?
 

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I would recommend an easily removable safety device, the series capacitor or the parallel zener diodes. You might even use a pluggable terminal that can be jumpered if needed (series capacitor). Then all of your setup and experimentation can be done safely, and when it has settled down and is stable, you can remove the protection completely for best sound, put it back in later on if more experimentation is in order.

If you use the series cap, choose a value that is an octave or two below your crossover freq so you don't mess that up.
 

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Discussion Starter #3
You might even use a pluggable terminal that can be jumpered if needed (series capacitor). Then all of your setup and experimentation can be done safely, and when it has settled down and is stable, you can remove the protection completely for best sound, put it back in later on if more experimentation is in order.
QUOTE]

Smart idea. On the "removing after experimenting" that's really a 2nd question. Obviously "volume" is the biggest risk but clipping and "mistakes" still remain. I suppose it's a matter of what's more important - absolute SQ or peace of mind ...:huh:
 

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Damage from clipping is always a risk. I suppose an approach is to design in a series capacitor an octave or two below the crossover frequency and leave it in. That should have minimal effect on the crossover design. I personally would probably take it out once I was really satisfied it was stable. Your call.
 

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Discussion Starter #5
If my math is correct a 100UF capacitor should do the trick. Now, I am thinking about leaving it in just for peace of mind. There are many negative opinions on bi-polar caps so I started looking at 100uf polypropylene etc. caps which range from$30 each to the absolutely absurd. I LOVE finding a bargain so voodoo aside anyone see a hard reason that I could not use polypropylene film cap designed for starting motors for $10 vs Audio Cap at $30-$800?

http://www.ebay.com/itm/AC-250V-100uF-100MFD-Polypropylene-Film-Cylindrical-Motor-Start-Capacitor-/231326632287?hash=item35dc24495f
 

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If my math is correct a 100UF capacitor should do the trick. Now, I am thinking about leaving it in just for peace of mind. There are many negative opinions on bi-polar caps so I started looking at 100uf polypropylene etc. caps which range from$30 each to the absolutely absurd. I LOVE finding a bargain so voodoo aside anyone see a hard reason that I could not use polypropylene film cap designed for starting motors for $10 vs Audio Cap at $30-$800?

http://www.ebay.com/itm/AC-250V-100uF-100MFD-Polypropylene-Film-Cylindrical-Motor-Start-Capacitor-/231326632287?hash=item35dc24495f
100uf is way too big. That would easily allow enough low frequency energy to burn out a tweeter. A 100uf capacitor makes at 200Hz high pass to an 8 ohm tweeter. (400Hz for a 4 ohm). Try going for two octaves below your active crossover frequency and use a cheap inductor to reduce the impedance of the tweeter at and below it's resonance.

I am speaking from first hand experience here. My stereo in 1990 was a four way active system with 24dB/octave crossovers. It was worth the effort (however I did have access to pro electronic design tools). And I do have 5 tweeters sitting around here with burned/broken voice coils from before I learned how to correctly protect them from turn-on thumps etc. Two fried while directly connected, three with 150uF capacitors.


Currently I am using KRK 10-3 tri-amped mid field monitors in my HT. You can get them on sale for 360 bucks sometimes and they are an amazing price/performance value. You can't buy the parts to build one for that much.
 

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Discussion Starter #9
The KRK 10's look like an extremely nice piece of kit for the price but not quite what I was trying to achieve. I wanted to be able to use a computer controlled active crossover to send seperate feeds to each. Using a room mic and PC based room correction the results where quite worth the effort IMHO. Could the same have been achieved much more simply? Probably but I love to tinker and I own that :coocoo:
 
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