Rebuilt 1875 Amp with new boards

[DC Dave]

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.

 

[DC Dave]

Here is the after picture. The heatsink became much larger!

 

[drummer_Dave]

Not bad, Ive always found making PCB's fun yet frustrating at times. Glad it worked out for you

Dave

 

[DC Dave]

Here is a closeup of the amp modules. A very basic schematic was used.

 

[DC Dave]

And the power supply.

 

[head_spaz]

Very nice. You done good.
How cheap were the boards?

 

[judtoff]

Looks very good. I personally like using the p2p method for 1875s, actually all chip amps I've done.
How does it sound?

 

[DC Dave]

Thanks,

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.

 

[drummer_Dave]

Would you mind sharing with us the company that manufactured the boards for you? Pretty Please

Dave

 

[DC Dave]

CustomPCB

 

[Paswa]

I have also made the same, but i'm confused with the Power supplt. can somebody tellll me about the trafo's VA rating and how much current will darw the LM1875 @ 4 Ohm??