Audio Amplifier protections

[aguantesoda]

¡Hola!, trato de hacer una protección para los Tips, y los Parlantes, para mi amplificador de audio, pero no sé como realizarlo.

Las características:

Vcc: 45 - 0 - 45
RL: 8 ohms

Si podés ayudarme...
Acá está el circuito.

Hello, I am trying to make a protection for the Tips, and the speakers, for my audio amplifier, but i do not know how.

The characteristics:

Vcc: 45 - 0 - 45
RL: 8 ohms

If you can help me...
Here is the circuit.

 

[gni]

Try http://sound.westhost.com/

 

[destroyer X]

Intall, please, the missed zobel filter.

Also the third output base was missed....just complete in your diagram...those bases are joined together.

I do not know why people forgot the stop resistors in series with the output bases...well...if working this way it is OK!

regards,

Carlos

 

[aguantesoda]

If a problem happens in the amplifier; the Tips will be hottest, and it is dangerous for the Tips. So, how can I install a protection for it?

si ocurriese un problema en el amplificador; los tips comenzarán a calentar y podría llegar a dañarlos. Entoces, como hago para proteger a los tips; y evitar q se quemen?

 

[Dick West]

Install a thermal switch in series with the incoming AC voltage. Study the schematics and wiring layout of the Hafler DH series. Mount the thermal sensing switch on the heat sink next to the output devices.

http://www.hafler.com/techsupport/pdf/DH-200_amp_man.pdf

 

[aguantesoda]

ok, thanks!

 

[AndrewT]

Hi,
that 39k collector load cannot be right.
1 or 2k should be nearer the required value.

 

[aguantesoda]

Hi,
that 39k collector load cannot be right.
1 or 2k should be nearer the required value.

yes, sorry; the 39k collector load it´s not right;
it is 3k.

here is the circuit

 

[aguantesoda]

I have made a Short Circuit Protection with an article post in http://sound.westhost.com/vi.htm

It is ok?

Source: + - 45V

RL: 4 u 8 ohms

 

[ifrythings]

I've seen lots of pro amps use this circuit (alost the same as yours but a bit modified

P.S look up uPC1237 IC, it can give you delay turn on to get rid of turn on/off thump , DC detection and load removal, and over-current load removal(via relay).

 

[teemuk]

The VI-limiter article at Rod Elliott's site is a bit "torso". The only useful information you get from it is that the circuit needs to be equipped with "flyback" diodes. The best information source about this subject I've seen so far is US patent 7,061,740 "System and method for protecting an audio amplifier output stage power transistor" by Eric Mendenhall. http://free.patentfetcher.com/

 

[mikeks]

Oh dear!

Mr Mendenhall has merely been allowed to patent prior art!

http://www.freepatentsonline.com/7061740.pdf

 

[mikeks]

Moreover, the notion that a thermistor may be used to implement automatic linear "derating" is flawed because thermistors are extremely non-linear.