Hello to all,
I am making speaker protection PCB design for my LJM L12-2 and I have few questions.
1) What is the name of the thing combination air coil and resistor? I forgot 😕 I think it should be there.
2) The fuses are originally 3A, isn't it too much?
And here is what I do:
Thanks!
I am making speaker protection PCB design for my LJM L12-2 and I have few questions.
1) What is the name of the thing combination air coil and resistor? I forgot 😕 I think it should be there.
2) The fuses are originally 3A, isn't it too much?
And here is what I do:

Thanks!
Parallel RL circuit - is that the name you are looking for?What is the name of the thing combination air coil and resistor?
P.S. I can't comment on whether or not the fuse values are appropriate.
3A is about 100 times too big. I don't think a fuse there will ever protect anything. Maybe keep it at 3A but put in series with speaker output.
Nice logo. How did you do that in Sprint-Layout? Take a long time moving curves?
Nice logo. How did you do that in Sprint-Layout? Take a long time moving curves?
I believe the parallel RL circuit is included to prevent the amplifier from becoming unstable (oscillating) at very high frequencies when operating into a capacitive load.I think it should be there.
I noticed most of speaker protections has no fuse. I assume fuses should protect the protection if it will be connected to some new test amp or so...
That logo took 2hrs to make. It is my hand-written signature and it is made from 3 pads, 66 circles and 16 tracks.
@Galu "Parallel RL" eh, not so sure. It has name ... it is name as some guy who invented it?
That logo took 2hrs to make. It is my hand-written signature and it is made from 3 pads, 66 circles and 16 tracks.
@Galu "Parallel RL" eh, not so sure. It has name ... it is name as some guy who invented it?
Regarding RL circuit, maybe you were thinking of Zobel network, Boucherot cell on the other hand is an RC series circuit only although it falls under the Zobel term as well.
Where are you going to buy a UPC1237? Ebay? Alibaba? May as well install a blob of glue. Use op amps or transistors, which still had leads last time I shopped.
Relays are so old fashioned also, when 50 amp nfets are a dollar. See Michael Bean circuit.
Relays are so old fashioned also, when 50 amp nfets are a dollar. See Michael Bean circuit.
How far back do you want to go ?
How about Maxwell,s theories on magnetism etc --a Scottish professor .
How about Maxwell,s theories on magnetism etc --a Scottish professor .
Where are you going to buy a UPC1237? Ebay? Alibaba? May as well install a blob of glue. Use op amps or transistors, which still had leads last time I shopped.
Relays are so old fashioned also, when 50 amp nfets are a dollar. See Michael Bean circuit.
I have few UPC1237 from Aliexpress, they works well. I played with Yamaha A-S500 clone (and I didn't figured out why two 47 omhs resistors run into smoke + other amps experiments) and my testing Yamaha speakers had been saved several times.
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How far back do you want to go ?
How about Maxwell,s theories on magnetism etc --a Scottish professor .
Yes, it might be Maxwell. Somebody somewhere named RL circuit like that, sounds quite sophisticated 😀
And yes, I am old fashioned guy having no TV over 15 years...
You may need to spend more time on the design of your circuit. A quick look at the pcb indicates the 3A fuse will do nothing; the 7812 will perform woefully as there is no input filter cap, and there is nothing to drive the relay coils.
You may need to spend more time on the design of your circuit. A quick look at the pcb indicates the 3A fuse will do nothing; the 7812 will perform woefully as there is no input filter cap, and there is nothing to drive the relay coils.
Fuses looks good there 😀, so it is everything... hmm, perhaps I will remove them. I forgot about input cap! Thanks for pointing it out.
The relays are run from pin 6 of uPC1237.
Surely R//L is a Thiele network, isn't it?
Yes! exactly! Thank you!
OP:
Definitely the fuse will be very slow, the thin wire of the conventional tweeter VC will melt much sooner, especially with 3A.
Can someone identify these components? Could I give you a photo of the reverse side of the PCB so that you can do a circuit survey ...
Definitely the fuse will be very slow, the thin wire of the conventional tweeter VC will melt much sooner, especially with 3A.
Can someone identify these components? Could I give you a photo of the reverse side of the PCB so that you can do a circuit survey ...
Attachments
That's a new word for my vocabulary, but at least I knew what the function of the network was! 😎Surely R//L is a Thiele network, isn't it?

The Thiele network reduces oscillations caused by capacitive loads, usually due to long speaker cables (while the Zobel network reduces oscillations caused by inductive loads).
Here you can see a simple circuit, maybe it helps.Technics SB1950, 75 watts RMS is the total allowable power, the circuit acts when that maximum is exceeded, the tweeter is the main beneficiary ...
it's a x-over, not a protection circuit
Here is the updated version with input cap.
If I will remove fuses, it will be quite big empty space there... 😕
So yes, to just to be clear, this is a nice (superior quality) Speaker Protection (as hi-speed design) with Thiele network. (The item each family must have!) I should do marketing
If I will remove fuses, it will be quite big empty space there... 😕
So yes, to just to be clear, this is a nice (superior quality) Speaker Protection (as hi-speed design) with Thiele network. (The item each family must have!) I should do marketing

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