Speaker delayed insertion, speaker protector, off set sensor

[zeraphine]

I have tested one like this on a Veroboard, with Two Relays unlike most with only one Relay, and Op Amp driving a Transistor, works really well, I adapted the design by Rod Elliot, it uses three Power resistors, and I have separated the resistors and the Relays from the main board because I though it was safer. I think Ill etch a board of this also Carlos, thanks so much for sharing

[zeraphine]

Come to think of it this design looks very similar to the one I built, I used Three 5W resistors unlike this one uses a single 50W one (will be expensive and hard to find), This design works carlos, but ill build this and see just in case

[destroyer X]

i do not think it is a good idea to try it.

I had problems related the timing, the DC sensitivity was not good, the relay have not closed contact in a decided way...one of them seems had vibrations during the operation.

I had tweaked but i really dislike the circuit....very unprecise...... i have stopped and decided to design my own by myself.

I never did that, as i am not too much motivated, i do not think they are really needed, fuses can do a nice job too...all my life i have used fuses and i have never regret about..so..i do not have good reasons, personally, to make it.

I gave a try on that because a book circuit, from a good designer...i was not satisfied.

Dx Blame does not have power on noises...so.... circuits not needed to mute it.....it is already silent..... the board has already fuses and i use to suggest people to use fuses....2.5A in series with the output line (to speaker) when using 8 ohms and 5.0A in series with the output line to 4 ohms.

I have made it because forum friends, as there are a lot of guys that likes these protections...was not for me.... as i am not motivated i have stopped to work on that.

Search for one schematic if you want..assemble, test and use it if you want....but do it under your own risk.

regards,

Carlos

[Mitchel]

Hello zeraphine,

Instead of the 50W aluminum housed resistor, you can use a NTC thermistor, lice CL-60, and the delay time can be set longer, by raising R1 value. This circuito is based around Rodd Elliott design, as you have already mentioned, and works very very well.

[zeraphine]

Hey Mitchel.

Thanks for the Info I will Try a NTC Thermistor, keep up the good work...

[zeraphine]

Im currently trying out the DC protection and Muting Circuit designed by Rod Elliot, I know what you mean, I actually dont need muting also, but Itll be really handy to have DC protection if something on the Amp fails itll protect my speakers at least, keep on posting your findings carlos,

Regards
Zeraphine.

[andrewlebon]

hi zeraphine
greetings see edwin paijs home page very nice compact dc
protector
thanking you
andrew lebon

[zeraphine]

Originally Posted by andrewlebon

hi zeraphine
greetings see edwin paijs home page very nice compact dc
protector
thanking you
andrew lebon

Can you please send me a link, thanks in advance

[zeraphine]

Ok I found the site, thank a lot Andrew, a very informative site...

[andrewlebon]

hi zeraphine
greetings change transistors to bc 547 bc 557 instead of bc 550 bc560

thanking you
for soft start see thread h class 900 watt have deciphered rod elliots soft start with small pcb andrew lebon