Finished my first LM3886 dual Mono Amp

[RCBandwidth]

Heat dissipation

I usually put a very small dc fan inside to move air out the back..It has not been a problem for other amps i have built. Bob C.

 

[pete.a]

Hallo Bernd

Hallo, ich habe Deine Message gesehen und bin total beeindruckt.Ich mache das auch und kann ein paar neue ideen immer gut gebrauchen.
Was kostet Dcih das ganze Material in deutschen Euro's?
Hier bei mir kostet mich das Meterial 60 Pfund
.Freu mich neues und ein paar tips von Dir zu bekommen.
Ich komme aus England und bitte Dich in Englisch zu schreiben.
Danke im voraus und Liebe Gruesse,

Peter

 

[Bernd-HH]

Hi Peter,

Thanks for the compliments.

All in all I have spend around 300€ for this Amp.

Kind Regards,
Bernd

 

[jaudio]

Re: Heat dissipation

I usually put a very small dc fan inside to move air out the back..It has not been a problem for other amps i have built. Bob C.

Nice Job. Have you measure the temp of the heatsink or internal volume with and without fan?

 

[RCBandwidth]

for jaudio

I will check the actual die temperature of the chip amps when the electronics are installed inside the cabinet.I always test my systems thoroughly after their finished.This includes an automated frequency linearity sweep and a temperature profile at full power.The temperature sensors are linked to my computer via a 1-wire bus(Dallas Semiconductor).

Best regards Bob Cottiers

 

[jaudio]

When I use a fan,I get about a 15 degree difference. How do you measure the die temperature?

 

[Evilsizer]

You cant measure the die temp since the amp chip does not have a temp diod that would report temps. It's like our computers the cpu has a temp diod that reports temps. what u will be able to measure is the temp of the heatsink itself. It wont be the die but you will get an idea of how hot it is running.

 

[kowu]

new guy here but I would like to say....wow you guys are very skilled!..excellent work!..I hope to be at the caliber of expertise someday...very impressive



keep up the good work.

 

[RCBandwidth]

Temperature monitoring

When I say I am measuring the die temperature,it means I am placing a temperature measuring device right on the LM4780 device(closely coupled),the actual chip temperature is the critical parameter to be measured(as opposed to the temperature of the heatsink).I hope this clears things up.

For Evilizer: If there is poor thermal contact between the chip and the heatsink, measuring the heatsink temperature will give misleading readings,of course the "substrate temperature" cannot be monitored,in this point i agree with you.

Thanks Bob C.

 

[Tekko]

Cute little amp