Here is the the revised board so far:
changes:
- added zobel resistor to silkscreen (can be mounted on top or bottom of pcb)
- widened the pin spacing on the zobel resistor to allow for larger resistors and more continuity on the groun plane
- changed the connection for the signal ground (SG) and power ground (PG) connection [credit to PA's suggestion for this minor change]
- added chipamp.com to the silkscreen
Let me know if you have any more suggestions. The difference in this rev.3 from the last rev.2 design is quite minimal, mostly cosmetic.
Let me know if you have any more features that you would like to have added to this pcb, as I am looking to order some relatively soon.
I still have rev.1 and rev.2 boards left, and will put up a clearance page soon to get rid of my stock.
LM3886 board here:
http://www.diyaudio.com/forums/showthread.php?s=&postid=554825#post554825
Also, let me know if you have any suggestions for the LM4780 board.
--
Brian
An externally hosted image should be here but it was not working when we last tested it.
changes:
- added zobel resistor to silkscreen (can be mounted on top or bottom of pcb)
- widened the pin spacing on the zobel resistor to allow for larger resistors and more continuity on the groun plane
- changed the connection for the signal ground (SG) and power ground (PG) connection [credit to PA's suggestion for this minor change]
- added chipamp.com to the silkscreen
Let me know if you have any more suggestions. The difference in this rev.3 from the last rev.2 design is quite minimal, mostly cosmetic.
Let me know if you have any more features that you would like to have added to this pcb, as I am looking to order some relatively soon.
I still have rev.1 and rev.2 boards left, and will put up a clearance page soon to get rid of my stock.
LM3886 board here:
http://www.diyaudio.com/forums/showthread.php?s=&postid=554825#post554825
Also, let me know if you have any suggestions for the LM4780 board.
--
Brian
At the bottom is a link to Carlos' schematic. Looks like you could make all of the changes on the rectifier PCB, but it may require a slightly larger board. You'd need to add a place for the 2.2k resistor, then the 100nF cap, and the 2.2k->100nF cap. You would then replace the 1500uF Panasonic cap you're currently using with a ~10000uF capacitor, which may or may not require changing the footprint for the capacitors on the amp PCB. Heh, a pain I know, but this is now pretty widely accepted as an improvement that yields significant[/B increases in sound quality.
Quote from Peter Daniel regarding sound quality improvements:
"...last week I tried Carlos' suggestion with regards to snubbers in GC supply (and big caps) and right away I liked the results. It is better even comparing to battery supply I was using up untill now. There is more bass slamm but at the same time the mids and highs are not veiled by anything (like it was in a case of regulators). There is more midrange presence and dynamics, but also what suprises me, more micro detail, something I wouldn't really expect."
I suppose it should also be noted that this would probably increase the price of a kit buy a few dollars ($5?). Possibly this Panasonic capacitor could be used in place of the 1500uF?
I personally think this would have a much larger improvement on over-all sound quality than the premium parts and is also a good deal cheaper. Just something to think about...
Quote from Peter Daniel regarding sound quality improvements:
"...last week I tried Carlos' suggestion with regards to snubbers in GC supply (and big caps) and right away I liked the results. It is better even comparing to battery supply I was using up untill now. There is more bass slamm but at the same time the mids and highs are not veiled by anything (like it was in a case of regulators). There is more midrange presence and dynamics, but also what suprises me, more micro detail, something I wouldn't really expect."
I suppose it should also be noted that this would probably increase the price of a kit buy a few dollars ($5?). Possibly this Panasonic capacitor could be used in place of the 1500uF?
I personally think this would have a much larger improvement on over-all sound quality than the premium parts and is also a good deal cheaper. Just something to think about...
m0tion said:At the bottom is a link to Carlos' schematic. Looks like you could make all of the changes on the rectifier PCB, but it may require a slightly larger board. You'd need to add a place for the 2.2k resistor, then the 100nF cap, and the 2.2k->100nF cap. You would then replace the 1500uF Panasonic cap you're currently using with a ~10000uF capacitor, which may or may not require changing the footprint for the capacitors on the amp PCB. Heh, a pain I know, but this is now pretty widely accepted as an improvement that yields significant[/B increases in sound quality.
Quote from Peter Daniel regarding sound quality improvements:
"...last week I tried Carlos' suggestion with regards to snubbers in GC supply (and big caps) and right away I liked the results. It is better even comparing to battery supply I was using up untill now. There is more bass slamm but at the same time the mids and highs are not veiled by anything (like it was in a case of regulators). There is more midrange presence and dynamics, but also what suprises me, more micro detail, something I wouldn't really expect."
I suppose it should also be noted that this would probably increase the price of a kit buy a few dollars ($5?). Possibly this Panasonic capacitor?
I personally think this would have a much larger improvement on over-all sound quality than the premium parts and is also a good deal cheaper. Just something to think about...
Sounds like an interesting idea. I will definately look into it.
--
Brian
re new design
IF you are changing the PS and the chipamp PCB, why not combine them into one board. this way there is more flexibility
about the real estate and would still have a compact layout.
It would require then about the same space as current both PCBs
This would also reduce the number of solder holes
vote for mute function to have room for cap for delay, as well as snubber circuit, instead of expensive premium components, as was suggested..
IF you are changing the PS and the chipamp PCB, why not combine them into one board. this way there is more flexibility
about the real estate and would still have a compact layout.
It would require then about the same space as current both PCBs
This would also reduce the number of solder holes
vote for mute function to have room for cap for delay, as well as snubber circuit, instead of expensive premium components, as was suggested..
Re: re new design
The reason that the rectifier board and amp board are seperate pcbs is so that they can be seperated from each other for better shielding, and also allow for a stereo configuration to be used with 2 amp boards per rectifier board.
I will work up a new rectifier board for the snubber setup.
--
Brian
SheldonD said:
The reason that the rectifier board and amp board are seperate pcbs is so that they can be seperated from each other for better shielding, and also allow for a stereo configuration to be used with 2 amp boards per rectifier board.
I will work up a new rectifier board for the snubber setup.
--
Brian
SheldonD said:
The option will still be there to keep them together as done by this person:
http://www.briangt.com/gallery/nigc-maarten/board
--
Brian
I'd have to agree, I think allowing the ability to seperate the boards outways the advantage of one consolidated smaller PCB. These amps are such a bargain I know I personally wouldn't mind chipping in a few extra dollars for the larger sized boards these modifications would require. That is, of course, only my personal opinion.
m0tion said:At the bottom is a link to Carlos' schematic. Looks like you could make all of the changes on the rectifier PCB, but it may require a slightly larger board. You'd need to add a place for the 2.2k resistor, then the 100nF cap, and the 2.2k->100nF cap. You would then replace the 1500uF Panasonic cap you're currently using with a ~10000uF capacitor, which may or may not require changing the footprint for the capacitors on the amp PCB. Heh, a pain I know, but this is now pretty widely accepted as an improvement that yields significant[/B increases in sound quality.
Quote from Peter Daniel regarding sound quality improvements:
"...last week I tried Carlos' suggestion with regards to snubbers in GC supply (and big caps) and right away I liked the results. It is better even comparing to battery supply I was using up untill now. There is more bass slamm but at the same time the mids and highs are not veiled by anything (like it was in a case of regulators). There is more midrange presence and dynamics, but also what suprises me, more micro detail, something I wouldn't really expect."
I suppose it should also be noted that this would probably increase the price of a kit buy a few dollars ($5?). Possibly this Panasonic capacitor could be used in place of the 1500uF?
I personally think this would have a much larger improvement on over-all sound quality than the premium parts and is also a good deal cheaper. Just something to think about...
Here is a quick workup of a rectifier board that you mentioned above. Let me know what you think.
An externally hosted image should be here but it was not working when we last tested it.
The placements are for the 10000uF caps you mentioned, and the larger 30mm will fit as well, with replacement of R1 and R2 on the bottom of the pcb.
--
Brian
Here is how the boards would hook up to each other (LM3886 board shown here has the same side pinout:
--
Brian
An externally hosted image should be here but it was not working when we last tested it.
--
Brian
Brian:
You work quickly =). Looks very good, I think this would work very well. One possible concern is that this does make the rectifier PCB much larger and this would raise the cost of the PCB sets considerably I think (maybe I'm wrong here). I believe Carlos' design used the 10000uF capacitors as the only filtering capacitors, but your design seems to use them along with the existing 1500uF capacitors. I think a lot of space could be saved if you moved the 10000uF capacitors onto the amplifier PCB (making that PCB slightly larger) in the place of the 1500uF capacitors. I think the other components could still remain on the rectifier PCB. This would change the order in which the components appear in parallel (instead of R1->C1->C2->(C3-R2), it would be R1->C2->(C3-R2)->C1, if that makes sense), but I don't think that matters electrically speaking. Please correct me if there is some glaringly obvious reason why this won't work, but it makes sense to me and would make the PCB set much smaller. Also, if this post isn't clear please tell me and I'll try to make some sort of visual representation of my idea when I get home. Thanks for your great effort!
You work quickly =). Looks very good, I think this would work very well. One possible concern is that this does make the rectifier PCB much larger and this would raise the cost of the PCB sets considerably I think (maybe I'm wrong here). I believe Carlos' design used the 10000uF capacitors as the only filtering capacitors, but your design seems to use them along with the existing 1500uF capacitors. I think a lot of space could be saved if you moved the 10000uF capacitors onto the amplifier PCB (making that PCB slightly larger) in the place of the 1500uF capacitors. I think the other components could still remain on the rectifier PCB. This would change the order in which the components appear in parallel (instead of R1->C1->C2->(C3-R2), it would be R1->C2->(C3-R2)->C1, if that makes sense), but I don't think that matters electrically speaking. Please correct me if there is some glaringly obvious reason why this won't work, but it makes sense to me and would make the PCB set much smaller. Also, if this post isn't clear please tell me and I'll try to make some sort of visual representation of my idea when I get home. Thanks for your great effort!
I just noticed that you changed the LM3886 PCB layout in that picture compared to the picture you posted earlier today in your LM3886 thread (in the upper right hand corner you moved a resistor and added a capacitor). Were these changes due to the snubber addition? I'm guessing not, but I thought I'd ask anyway.
m0tion said:
I didn't want to change the order of the components, but I did make the layout more compact after the initial layout:
An externally hosted image should be here but it was not working when we last tested it.
m0tion said:
The resistor and cap are for the muting circuit. The resistor sets the current for the mute pin, and the cap is for a turn-on/turn-off delay.
If I was to use the snubber rectifier board, I will be adding pads for the smaller decoupling caps, instead of the 1500uF. The design would allow for both,
--
Brian
m0tion said:
Here is what I referring to with regards to allowing both setups:
An externally hosted image should be here but it was not working when we last tested it.
This way the .1uF decoupling can be installed along with a 100uF cap (100uF would fit stretched out to fit in the larger spacings). If the standard 1500uF setup is desired, than the extra holes would be ignored (or even stuffed on the bottom side for experimentation).
--
Brian
I updated the picture above a few posts of the 2 boards together to show the current LM3886 with the extra pads for decoupling caps. This should show what I am referring to. Here it is again:
The total size of the 2 boards together is 1.2" for the amp, and 2.4" for the rectifier board = 3.6", and for a 2 channel pcb, it would be 7.2", which is still reasonable. What do you think?
--
Brian
An externally hosted image should be here but it was not working when we last tested it.
The total size of the 2 boards together is 1.2" for the amp, and 2.4" for the rectifier board = 3.6", and for a 2 channel pcb, it would be 7.2", which is still reasonable. What do you think?
--
Brian
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