Brian's LM3875 REV C boards

[wigginjs]

Everything looks wonderful to me, I can't think of anything to make it better.

The LM3875 and LM3886 seem like pretty similar chips to me. With you doing your new LM3886 boards it seems redundant tohave an LM3875 board available as well. Perhaps you should pick the better of the two chips and simply focus on that, unless there is a big difference between them that I don't understand. I just don't think it makes sense to have two choices available that are so similar.

[BrianGT]

Originally posted by m0tion
Everything looks wonderful to me, I can't think of anything to make it better.

The LM3875 and LM3886 seem like pretty similar chips to me. With you doing your new LM3886 boards it seems redundant tohave an LM3875 board available as well. Perhaps you should pick the better of the two chips and simply focus on that, unless there is a big difference between them that I don't understand. I just don't think it makes sense to have two choices available that are so similar.

My plan is to get another batch of the standard LM3875 boards made with the small modifications made, and a new batch of boards made with the LM3886 and the snubber setup, and I will compare the two. With the board pinouts being the same for hooking up connections, the LM3875 boards will work together well with the rectifier board on the LM3886 pcb, so I can also try the new power supply setup with the LM3875.

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Brian

[sbolin]

Brian, is the LM3886 board the same size as the rev B LM3885 board? Just wondering if it will fit in one of Peter's chassis without modification. The PS board isn't the same, of course, but I think it should still fit in the chassis, just need to drill new mounting holes. Looks very nice to my untrained eye, can't wait to see/hear the final product.

[BrianGT]

Originally posted by sbolin
Brian, is the LM3886 board the same size as the rev B LM3885 board? Just wondering if it will fit in one of Peter's chassis without modification. The PS board isn't the same, of course, but I think it should still fit in the chassis, just need to drill new mounting holes. Looks very nice to my untrained eye, can't wait to see/hear the final product.

The LM3886 amplifier board is exactly the same size as the LM3875 board. The mounting holes are the same as well, so it will work in peter's chassis.

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Brian

[sbolin]

One last question, Brian. I am now confused a bit, I was thinking I was in the LM3886 thread. Will there be a LM3875 rev C board and the LM3886 board? So two separate boards?

[BrianGT]

Originally posted by sbolin
One last question, Brian. I am now confused a bit, I was thinking I was in the LM3886 thread. Will there be a LM3875 rev C board and the LM3886 board? So two separate boards?

I am going to handle the new LM3886 boards first, and then once I get the order placed and finalized, I will work on getting the LM3875 rev.3 boards done. The changes are quite minor for the rev.3 boards compared to the rev.2 boards, so I would like to see how the LM3886 boards work out first, and possibly build more features into the LM3875 rev.3 pcb set based on this. I still have about 50 rev.2 boards available, and I will take orders for them again soon.

In the end, there will be 3 pcb sets offered, each with 2 amp boards and 2 rectifier boards:
- LM3875
- LM3886
- LM4780

Let me know if you have any more questions.

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Brian

[homer09]

If its not too much to ask, any estimates on time for each stage?

[sbolin]

Thanks for the quick replies, Brian.
If possible, I would like the rev C board to have the 'standard' PS (like the current rev B board). In the LM3886 thread you mentioned that the LM3886 would be where the new ideas and experiments take place, and I think that is a good idea. I like that board, but for the LM3875 think a simple design is best.

And yes, I'm with homer09...any time tables?

[homer09]

sbolin, i side with you on the time tables, but i would like to see the snubbered power supply for the rev3 boards of the lm3875. and i think im far from being alone on that one. the complexity of the snubber isnt much greater either, only larger caps and extra pair of resistors...

but anyway, correct me if im wrong brian, you're planning on desiging a rectifier board capable of a snubbered or normal supply right (up to the builder's preference)?

[BrianGT]

Originally posted by homer09
If its not too much to ask, any estimates on time for each stage?

Originally posted by sbolin
Thanks for the quick replies, Brian.
If possible, I would like the rev C board to have the 'standard' PS (like the current rev B board). In the LM3886 thread you mentioned that the LM3886 would be where the new ideas and experiments take place, and I think that is a good idea. I like that board, but for the LM3875 think a simple design is best.

And yes, I'm with homer09...any time tables?

The form factor of the LM3875 board will not change, and it will be compatible with new power supply board on the LM3886 set.

As for time frames, if people are interested in the LM3886 boards, I will order them Friday and start taking pre-orders for them.

As for the LM3875 boards, I will sell the remainder of my rev.2 inventory starting within a week, and work on ordering the boards for that after I get the LM3886 boards ordered.

All boards are ordered with a 2 week leadtime.

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Brian