My ACA Amp

[surfatwork]

1. You have wayyyyy too much heatsink paste.
2. Your mount suggests that the MOSFET is not properly in contact with the sink. Seems tilted.
Please see how to mount the mosfets properly, else they will overheat and blow.
Check diyaudio forums for proper heatsink sizing. Vertical fins are much better, so see if you can orient them that way.
The alpair has only 87. 5db sensitivity. Limited volume with the aca.

 

[sarathssca]

1. You have wayyyyy too much heatsink paste.
2. Your mount suggests that the MOSFET is not properly in contact with the sink. Seems tilted.
Please see how to mount the mosfets properly, else they will overheat and blow.
Check diyaudio forums for proper heatsink sizing. Vertical fins are much better, so see if you can orient them that way.
The alpair has only 87. 5db sensitivity. Limited volume with the aca.

MOSFET contact is ok i think as the screws on the MOSFET are quite tight and heatsinks are getting very very hot .. after some 15-20 min not able to hold it for more than 1-2 sec.. will check changing the position of the heatsink to vertical fins ..

 

[jls001]

MOSFET contact is ok i think as the screws on the MOSFET are quite tight and heatsinks are getting very very hot .. after some 15-20 min not able to hold it for more than 1-2 sec.. will check changing the position of the heatsink to vertical fins ..

Not able to hold for more than 1-2 sec sounds like your heat sink is inadequate. You need bigger.

 

[sarathssca]

Last weekend took the amp to native and play it with sony ss-rv900 speakers (3 way speaker) from Sony Hi-fi setup. Though the hi-fi setup was rated at 150w+150w, got decent (but not much loud, may be little louder would have been better) sound from ACA played with mobile as input source. But when played it from a laptop (vnc player) got nice loud volume from the ACA amp driving the these speakers .. ..
5w amp looked very nice loud with speakers rated at 150w each..

Now may be need to get a nice preamp for the ACA amp with gain, as with laptop as source ( seems which has good gain compared with mobile phone) sounded loud enough and some updates to handle the excess heat that my amp is generated with my given heat sink..

 

[niftianmadhur]

Nice looking amp. This is a good DYI stuff. congrats. I wish the wires were not much visible from the top. Where did u get the spikes from? It looks good and stury.

 

[sarathssca]

Is anyone using 24v power supply with aca amp??
I tried to search 24v laptop power supply but couldn't find it and all were saying only 19v laptop power supply available ..

 

[saikatbiswas82]

Finally assembled and got the amp sing ..

- no thump sound at power on or off .. it's smoothly starting and stopping ..

- finally used 4 strands of cat-6 cable for each output positive and negative on one side.. my soldering job little ordinary only

- I couldn't get the bolt/connectors for mounting the board and MOSFETs on the heatsink as in other aca builds here .. I have used normal screw and nuts for this as in photos but faced difficulty in properly fitting the board and MOSFETs. Needed to put the screws from behind the heatsink and put the bolt on top as I couldn't put the bolt behind the heatsink .. also the holes for MOSFETs and PCB were not properly aligned as my heatsink has horizontal fins ..

- my heatsink r of size 190mm *95mm *33mm.. is it ok .. while running it's getting very very hot .. i haven't done any mod and these r running on 19v 90w power supply.. do I need to use bigger heatsink or small fan or another additional heatsink and fix it over these 2 heatsinks ..

- volume out of the alpair 7p speakers r coming little less only .. current volume is ok for near field .. now need to run these to break in the alpair 7p driversView attachment 28877View attachment 28878View attachment 28879View attachment 28880 ..

I also paired my alpair 7.3 with my AmpCamp and found its not enough powerful for alpairs.