Not recommending series caps but if you have to...
If high currents are involved the only really safe way (for the cap) to use back to back electrolytic caps is to jump across the caps individually with high current, low forward voltage Shottkey diodes that conduct the current when it is flowing in the direction opposite to that which the electrolytic cap is labelled.
I have used this to tune out the inductance of large moving magnet linear motors, but it is still a non ideal method to accomplish this as motor run caps are much "sturdier" and bipolar caps are getting larger in value every year.
Dave
If high currents are involved the only really safe way (for the cap) to use back to back electrolytic caps is to jump across the caps individually with high current, low forward voltage Shottkey diodes that conduct the current when it is flowing in the direction opposite to that which the electrolytic cap is labelled.
I have used this to tune out the inductance of large moving magnet linear motors, but it is still a non ideal method to accomplish this as motor run caps are much "sturdier" and bipolar caps are getting larger in value every year.
Dave
Ping. Best approach now-a-days to driver protection?
How about this little Velleman kit or equivalent home-brew boards? Any dangers to this approach? Limitations?
https://www.parts-express.com/velleman-k4700u-2-channel-loudspeaker-protection-kit--320-264
Historic note: in days of yore, a major concern was systems that produced high frequency harmonic distortion notes, esp, high up frequencies that fried tweeters.
Ben
motional feedback, the final frontier
How about this little Velleman kit or equivalent home-brew boards? Any dangers to this approach? Limitations?
https://www.parts-express.com/velleman-k4700u-2-channel-loudspeaker-protection-kit--320-264
Historic note: in days of yore, a major concern was systems that produced high frequency harmonic distortion notes, esp, high up frequencies that fried tweeters.
Ben
motional feedback, the final frontier
that was 30 some years ago on the preamp transient - the culprit besides myself forgetting was a Citation IV feeding a Citation 12. Tell me how to juggle the heater, power supply and internal constants so it can't happen without any relay protection. The line stage was a 12ax7 cascade pair with cap coupled NFB from 2nd plate to 1st stage cathode. Medium mu anode followers make nice buffers but I've not built for ~20yr. I paid about $9 each for 600vdc 600uF polypropylene
Ben,
The D-Fend is probably the most robust and adjustable driver protection technology available:
D-fend? Loudspeaker Protection Technology | Eminence Speaker
It can handle (dissipate) 300 volts (more than enough to protect against "Flame Linear" PSU rail voltage ;^) and still sound musical as it clamps down.
Peak and RMS voltage and hold times can be adjusted individually at different frequencies to make virtually any loudspeaker "bulletproof", assuming they are set conservatively enough.
I have a never used earlier version of the unit I'd sell for a bit over the shipping cost, PM if interested.
Art
Sure seems the ultimate protective device. Alas, well outside my budget.
DJK, do you know the joke "if you want to smoke here, you have to go elsewhere"? I'm not looking to switch expensive amps, just to add protection. Likely true of OP too.
Ben
" I'm not looking to switch expensive amps, just to add protection. Likely true of OP too."
It can all be done externally as well.
I've been thinking about a crowbar circuit that could attach right at the speaker leads.
I change the filter in either the EQ or the crossover, or the amp, whatever is the easiest.
It can all be done externally as well.
I've been thinking about a crowbar circuit that could attach right at the speaker leads.
I change the filter in either the EQ or the crossover, or the amp, whatever is the easiest.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.