App Output-DC-Detection with LED Indicator

[U230421]

Trip occurs at around -/+2.5 volts DC.

Is that low enough for dc protection?
This one does trip at +/-0.2V:
DC & Temp protection with limited resources

 

[Mooly]

Its a pretty standard type of circuit so the amp designers must have thought it OK.

2.5v only gives 800mw dissipation in an 8 ohm load and so any speaker that such an amp would be used with should be safe.

 

[Mooly]

Optos 🙂...

LT includes quite a few common parts in its standard library. Alter the value of R7 to suit the opto current required.

 

[Mooly]

This shows the speaker being fed from an amplifier with a rising DC offset. The speaker is connected via a solid state relay. Once the offset reaches around +2.5 volts the speaker is disconnected. The audio is 1kHz here.

 

[wgh52]

OK folks,

I've made the decision to accept a set of potential electronic and financial risks 😉 and do this:

For general retrofitting (e.g. my Trio Receiver, Vincent Monos, friends' applications) I am building a 15x22mm(32mm with 4xM3 mounting holes) DC detection & display board. This piggy backs on my 15x22mm(32mm with 4xM3 mounting holes) one-channel SSR board. The DC detector is based on the optocoupler SFH620A and does the SSR/V+ on/off switching, a green LED shows "SSR On" and a red LED signals "DC warning".

For my 4-way active DIY speakers, a 20x20mm board is designed to piggy back on the specialised SSR for this case which fits on the PwrAmp boards' Output Connectors and substitutes the "old" DC detector with electromechanical relay for the 4 Outputs (which avoids a bunch of cabling and connections).

Thanks for all the valuable input and work done! It will take a few weeks to build all that...

A happy, healthy Christmas Time to all!
Winfried

 

[Mooly]

That sounds like a plan 🙂

Merry Christmas