Very Simple, Almost Universal, Speaker Protection Circuit

[delecoy]

👀

 

[EUVL]

Fran has tested the latest version this weekend.
It actually works beyond the minimum 24V and maximum 100V total rail voltages.
We shall make some final check with the PCB shop, update documents, etc. next week.
Then we should be ready to go with the GB.


Thank you for your patience,
Patrick

 

[woodturner-fran]

Yes, I carried out some extensive testing this weekend, along with some of the documentation. Happily, all worked as expected, triggering of the protection is very repeatable, and the working supply voltage range was verified.

I will prepare the last few details in the coming days and post the information for the group buy during the week.

fran

 

[woodturner-fran]

Hi all,

Testing and preparation is now complete, so the group buy is now open at

W

Thread 'Group Buy - Very Simple Almost Universal Speaker Protection'

2025-04-10 9:26 pm

What is offered:

4x pieces of a speaker protection module as shown in the thread here:
https://www.diyaudio.com/community/...-universal-speaker-protection-circuit.415149/
enough for 2 stereo amplifiers.

Since the MOSFETs used are tricky to solder effectively at home, the boards will be provided with the MOSFETs already soldered. The rest of the parts will need to be supplied by the subscriber. They are easily available and in stock at Mouser, DK etc. The modules use SMD parts with the smallest at 0603, but most are larger than this - I'm only saying...

• woodturner-fran
• Replies: 37
• Forum: Group Buys

• 

Fran

 

[kouiky]

Hello,

I have a few questions that I hope are not too invasive.

Can you clarify why the circuit must be run from the same rails as the main amplifier? If one rail goes down, does the protection circuit immediately open the relay? My last question is, what kind of failure conditions will trip the circuit to open the relays?

Appreciated!

 

[EUVL]

Can you clarify why the circuit must be run from the same rails as the main amplifier? If one rail goes down, does the protection circuit immediately open the relay?

Yes, and precisely for that reason.

Also the relay MOSFETs are protected from excessive voltage during switching of inductive load by clamping diodes to both rails.

My last question is, what kind of failure conditions will trip the circuit to open the relays?

Loss of any one of the rails, differential DC voltage at the amplifier output.

The working principle of the DC trigger is very similar to post #5. Difference is in the details.


Patrick

 

[EUVL]

Many many thanks to Fran again who has been testing the latest version in his F5EXC with +/-50V rails over many evenings.

He also repeated the trigger timing test multiple times at +/-12V, +/-25V and +/-50V to confirm that they are consistent with the design values.


Patrick