My "el cheapo" LM1875 amp

[Sparky OR]

This is a step down from my earlier LM1875 stereo amp where I attempted to do things "right" as much as possible, quality case, gold RCA jacks, selector switch, attention to grounding, toroid 160VA xfmr, etc. This one used a scrounged satellite receiver for the case, which worked out really well, transformer mounted to existing threaded pemnuts. The case is easy to work with due to the removable front panel and faceplate. I even was able to use the existing AC input and fuseholder holes. I used a Radio Shack 25.2V 3A transformer (about $12), rear panel scrounged from an old computer speaker, kit50 amp PCB's, mounted to a chunk of aluminum. I did use a BrianGT PS board, replaced the 1500uF 50V caps with 4700uF 35V. There is a 2 wire AC cord, so no external ground. All grounds return to PS PCB, except for the inputs. There is a 10k stereo minipot for Vol control. Input wiring is Home Depot plenum cat 5 wire conductors, I don't think they are teflon as they stripped too easily. It is quiet, sounds better than my earlier attempt for some reason. PS gives only +/-15VDC and is not too stiff, it varies when turned up all the way.

[michal]

Looks nice.

Having a dedicated PS for each channel would help a bit with the sagging V under load. Given low cost of it, should be worth it.

Are you sure it's a 2A and not a 3A model?

[Sparky OR]

It's stamped 3A. Dual supplies would push me away from the cheap and simple concept that I was shooting for with this one. But I will take some measurements with it running only one channel. I was surprised at the ample bass as it is, sag and all. I would like to make my own PCB with a better coupling cap.