Adding a "Protection LED" on an amp

Status
Not open for further replies.
Jump to Latest
Bricolo

Bricolo

Member
Joined 2002
#1
I've seen many commercial amps that have a "protection" LED, that lights when the amp goes in a kind of protection mode, in example when it's oscillating


Has anyone a schematic for this?

PS: there's no need for short circuit protection; since it's for a gainclone. My principal aim is to see easilly if the amp oscillates

Thanks
Alex
 
#3
I saw a schematic in the Slone
audio book for an usual DC offset
detector with oscillating output
detection. It had output series resistor andinductor.
The voltage sense taps off the inductor..
I don't know too much about it, I wasn't interested in the design......

I guess the voltage rises at oscillation
triggering the DC offset detector.

Or make a high frequency detector
:clown:

high pass filter at > 50khz
that triggers when voltage > threshold?

:dead:
 
#6
are these oscillations always a high frequency?
highpass+ threshold?
I have been thinking a zero crossing detector would capture all DC problems but the oscillating case is not detected. maybe setecting something in the feedback path?
 
#12
Sources foe such circuits

In Randy Slones books you can find simple circuits for clippping indicators, oscillation indicators, and circuit that provide speaker DC protection. delayed tuern on, and thermal protection with an LED flashing in various ways to indicate the sstatus.

Rod Elliot has clipping indicator as well as the SIM (Signal Impairment Monitor).

These are copy writed so they can't be posted here, but are easy enough to look up. All are fairly simple to build.
 
#14
You can use it even if it's copywrited. You just can't sell it or post it. You can go to Rod Elliot's site, print out your own copy and build it. What you should not do is post a copy here. Ditto with Slones except I don't think it posted on his web site. You could go to your library and if it is there make a copy, go home and build it.

Of course if you want to put it in a product for resale, the appropriate course would be to contact the individuals and work a deal. In either case, there may not actually be a patent so perhaps you could use it anyway so long as you didn't republish the schematic.
 
#15
sam9 said:
You can use it even if it's copywrited. You just can't sell it or post it. You can go to Rod Elliot's site, print out your own copy and build it. What you should not do is post a copy here. Ditto with Slones except I don't think it posted on his web site. You could go to your library and if it is there make a copy, go home and build it.

Of course if you want to put it in a product for resale, the appropriate course would be to contact the individuals and work a deal. In either case, there may not actually be a patent so perhaps you could use it anyway so long as you didn't republish the schematic.
Click to expand...


the problem is finding it in a french library...
 
#19
JojoD818 said:
Sam,

I don't have any intention of doing wrong to anybody, especially in this forum. I apologize to anyone I unintentionally did wrong.

I came to this forum to learn, not to make anybody mad. 🙂

I guess I should be more sensitive when posting other people's property. 🙂

Jojo
Click to expand...


Rod's images are always tagged with the ESL logo, so I think he doesn't mind
 
#20
"I don't have any intention of doing wrong to anybody, especially in this forum. I apologize to anyone I unintentionally did wrong."


Don't worry, I wasn't angry. I was just trying to explain some of the complexities. I'm married to someone who co-authored one of the early papers on intellectual property and the internet, so I get a lot of input (and cautions) on that subject whether I want it or not. The situation remains unclear in a lot of ways. Someone like Rod Elliot may be quite mellow about what you post, calculating that it serves to send more business his way. Another person (or company) might take an exteme position and attack with an army of lawyers.
 
Status
Not open for further replies.
Top Bottom