Proud new owner of 4ch LM3875


It's finished :D

It sounds quite amazing. :) Very smooth and detailed. I ran it in with some old speakers I made but it has graduated to my proper speakers now, I can't stop listening to it, it keeps making me grin because it sounds so good.

I know this won't be very interesting to everyone because it's very basic stuff but I'm chuffed to bits.

I have used 2 dual mono kits and a shielded 500VA transformer, it's in a 2U 19" rackmount case which while not a pretty thing, works fine and it wasn't too tricky to assemble because there is loads of space.

I have shielded all the mains power cables with knitted copper wire tubing, I don't know if it helps cut down on EMF but is certainly won't hurt. I used socket 7 processor heatsinks because I had loads spare for old types of processors at work which I'll never need to use.

So far I have only grounded the CHG from the boards so there is a very slight hum if I put my head right next to the woofer. I'm reading up on grounding now. :) This is very useful actually Linky

I have started building the capacitor and snubber section of the snubberised PSU from the Db dungeon site - one of CarlosFM's designs. 1 board is done, 3 more to go. I'll pop them between the power and amp boards and see what sort of difference they make.

I'm dedicating the amp to the 6 diodes and 1 capacitor which paid the ultimate price in the construction because I mixed up the + ground and - ground wires.

Thanks for your help in answering my questions in the other threads, much appreciated. :)

Here is a pic I took on my phone when I had done the first 2 channels.


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Good job :) . I just finished building my first hi-fi amp and speakers the other day. I used a Brian GT LM3875 kit w/ a snubberized PSU. Mine has been running 24 hours a day since this weekend when I finished construction of the lot. I wonder in every few hours to sit and listen at the new goodies.

There's a certain sense of satisfaction one gets from appreciating something that they put together on their own.

Do you have any pics of the final product?
Thank you :) Congrats to you on your new amp and speakers too :)

Yes, I agree, it's the satisfaction from building kit that makes it special.

I have got so much more out of building speakers and sub boxes for the cars than I put in. I may have a go at some other things when I have finished adding bits to this amp. Maybe a DAC.

I haven't got any decent pictures, just a few on my phone which isn't a very good camera. I want to set a small perpex window in the front panel and maybe etch "gainclone" in it, I also need to mount LEDs from the power boards in the front panel so I'll wait until it's finished before taking any pictures.