Class G rail supply indicator

Hi guys. I upload a circuit that indicates the +/-Low rail to +/- high rail transition by mean of a Led but I have some doubts respect to it, first if this circuit can be added to Mosfet step driver circuits. Any suggestion you have, let me know. Thank you
 

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It's not hard to improve on this circuit but yes, it should work fine on any class G amp.
1. It runs on the high voltage rail wasting power and hot dropping resistors.
2. It uses (waste) two stages but is two diode drops inaccurate.
If accuracy matters then you may want to make it more complicated, but I would just use one transistor in common base mode off the lower rail. Or color code a VU ladder to indicate the class G threshold.
 
Thank you Steveu for replying. Well, I have to experiment with this circuit if it works fine in class H whose step drivers use Mosfets to switch between rails. Steveu, I have seen several class H amplifier with Leds glowing in the step driver circuits, are they the same as this on?

I'd have to see the schematic but I suspect not. Leds are often used as ~2V voltage references.
 
Thank you Steveu for your response. Well, I have seen a Led glowing in some class H amplifiers but I have not read the diagrams of these unknown amplifiers. You are right, the circuit I posted is to monitor the changes between rails therefore it would be necessary for a manufacturer to add a circuit like that. I will go on researching class H diagrams in the Web. Do you have any schematic of step drivers for this kind of amplifier? Thank you beforehand for your help.
 
Hi
Why do you even need such indication?
The article is just another cash grab by Doug - the circuit will work but has its pitfalls as noted above.

Yes Nauta. Only I wanted to build a circuit to know the chage of supply rail.

Hi Andrewlebon thank you for answering. The circuit looks interesting and I will build a PCB to test this step driver. Andrew, thank you for your help. Does that circuit belong to any original audio brand?
 
Hi Eliasib
greetings i found this on the net what do you want to build there are better
and more powerfull circuits to build
warm regards
Andrew

Yeah, Andrew , you are right however it is difficult to find step driver circuits for class H amplifiers explained on the net. I have several step driver circuits but they belong to manual service of class H amplifier sold in the market. I read a Crest Audio manual service, Pulse Series that explains how the opamp based step driver works. Thank you for replying bro