Rebuilt 1875 Amp with new boards

I few years ago when I first started experimenting with chipamps I threw together a amplifier based on the LM1875 out of spare parts and connected it to a PC and an old NEC SCSI CD-Rom. It has gotten used everyday. Occasionally I get the urge to open it up and tweak something. It has received a new pot, input jacks, power supply, etc. Then one day it dawned on me to take it one step further.

For the first time I started playing with Eagle and decided to design some pcbs for the LM1875. Inspiration came from Peter and Brian's original LM3875 boards. I found a place online that quickly made some prototype boards for cheap. I learned a lot and I'm happy with the results. The sound is clear and noise free.

This is a picture of the original amp.


  • front-top-internal-old-psu.jpg
    93 KB · Views: 507

The boards cost $50 shipped for 8 amp channels and 4 power supplies. No solder mask, no silkscreen. I received them in one week after placing the order. Not near the quality of the boards that I received from Audiosector, but for a prototype, its better than I expected.

The amp sounds good. It runs off +-20volt rails so I am looking at about 17 watts per channel. The highs are clear, and the lows are present. Its dead quiet.

I now need to think of a small bookshelf fullrange speaker to go with it.


  • new-pcbs.jpg
    91.5 KB · Views: 399