1000W Simple PA Amplifier

[apexaudio]

hi apex sir,
added extra 4 pair outs, now the heat is 80 degree ,in cliping level.

Fan have no efect on your desk, outside of the case, air must flow only thru heatsink.

 

[wattaniya]

yes sir, the fan is only for one heatsink,
the new heatsink is without fan, and the heat is very less.

 

[thimios]

PCB for 12-LED-Stereo-Version.

Regards Olaf

It is useful if we have schematic diagram.

 

[olafk]

It is useful if we have schematic diagram.

Was created directly from the layout of Mile.

regards Olaf

 

[olafk]

very fast, no warranty!
regards

 

[apexaudio]

very fast, no warranty!
regards

Nice schematic thanks, only 68R must be connect to GND not to +5V,
Regards

 

[olafk]

Nice schematic thanks, only 68R must be connect to GND not to +5V,
Regards

Oh, sorry.

 

[boss2009]

Oh, sorry.

Hello Apex... my amp is ready for testing. Can i use MJE340 instead of BD139/BD681? if its ok .. what will be the values of R13 & R14? this is
without using trimmer to adjust bias. Thanks so much for support.

 

[apexaudio]

Hello Apex... my amp is ready for testing. Can i use MJE340 instead of BD139/BD681? if its ok .. what will be the values of R13 & R14? this is
without using trimmer to adjust bias. Thanks so much for support.

You can use mje340 instead bd139 with 2k2/1k resistors.

 

[boss2009]

You can use mje340 instead bd139 with 2k2/1k resistors.

Thank you so much for quick reply Apex.

Best Regards and TC

 

[boss2009]

You can use mje340 instead bd139 with 2k2/1k resistors.

hello sir Mile.. just done quick test without heat sink .. i have dc offset of 35mv for 1 channel and the other have 125mv. i hope u can suggest where to look for error. i used for test 35vac trafo and vdc reading is at 54 with 8 pcs 10,000uf/100 caps. thanks and regards

 

[apexaudio]

hello sir Mile.. just done quick test without heat sink .. i have dc offset of 35mv for 1 channel and the other have 125mv. i hope u can suggest where to look for error. i used for test 35vac trafo and vdc reading is at 54 with 8 pcs 10,000uf/100 caps. thanks and regards

There is no error, without adjust and meaching input pair dc offset can be +/-300mV.

 

[boss2009]

There is no error, without adjust and meaching input pair dc offset can be +/-300mV.

thanks for clarification Mr. Mile...

Best Regards

 

[boss2009]

There is no error, without adjust and meaching input pair dc offset can be +/-300mV.

Mr Mile.. I put 1k trimmer for DC offset and series with 470R (R4) . offset is now at 13mv. Voltage accross Q11, Q12 BE reads 0.56V and Q5, Q4, Q3, Q9 & Q10 is heating up moderately increasing even without signal at input. Output tranies not heating up. By the way CE of MJE340 reads 2.2VDC. Can you give you analysis bout this.. Many thanks

 

[boss2009]

Mr Mile.. I put 1k trimmer for DC offset and series with 470R (R4) . offset is now at 13mv. Voltage accross Q11, Q12 BE reads 0.56V and Q5, Q4, Q3, Q9 & Q10 is heating up moderately increasing even without signal at input. Output tranies not heating up. By the way CE of MJE340 reads 2.2VDC. Can you give you analysis bout this.. Many thanks

I now replaced 1k trimmer and 470R with 560R. DC offset is now at 10mv..

 

[apexaudio]

Mr Mile.. I put 1k trimmer for DC offset and series with 470R (R4) . offset is now at 13mv. Voltage accross Q11, Q12 BE reads 0.56V and Q5, Q4, Q3, Q9 & Q10 is heating up moderately increasing even without signal at input. Output tranies not heating up. By the way CE of MJE340 reads 2.2VDC. Can you give you analysis bout this.. Many thanks

VAS transistors work in class A and must be on heatsink with outputs.

 

[boss2009]

VAS transistors work in class A and must be on heatsink with outputs.

Thank you Mr. Mile.. i'll do further test when it will be mounted to heat sink and proper signal input.. Best Regards

 

[olafk]

Hi, here the VU again. I want to mount it behind dark Plexi. The other LEDs are used to show temperature. If it work, I will take the touch sensors and an Arduino for on / off and mute. Let's see ... It's playground 🙂

regards Olaf

 

[apexaudio]

Hi, here the VU again. I want to mount it behind dark Plexi. The other LEDs are used to show temperature. If it work, I will take the touch sensors and an Arduino for on / off and mute. Let's see ... It's playground 🙂

regards Olaf

Old BGW amp with similar VU.

 

[olafk]

wow, everything good comes back 🙂

regards