Hello everyone, I'm new to the forum and would like to share my first LM3886 amplifier build. It all started from a new sound card purchase (Auzentech X-Fi Forte) and a small issue with my Logitech z-2300 2.1 system. Initially I was planning on upgrading the Logitech sub and satellites, but once I ripped the guts out, it seemed like a waste. I quickly sold the setup and used the money toward the following build.
The build started with lots of research and with the help of this forum and similar others, I was able to put together a parts list. After 2 weeks of waiting and driving around like a maniac trying to piece things together, I was able to gather all required parts minus a 50k ohm dual gain audio pot. This can wait till I'm closer to being finished.
So far I was able to put together the power supply and test the output voltage.
Some amp and power supply components
hand matching resistors
one rail completed
both rails completed
testing output dc positive voltage 37.3
testing output dc negative voltage -37.3
My plans for the weekend are to begin the amp channels build along with customizing my aluminum enclosure for the entire setup.
I would like to hear some ideas on bookshelf speakers and a custom sub/amp. For now I'll be using Polk monitor 30 to run off the lm3886 and a self powered Onkyo sub. I plan on building the crossovers and buying separate components along with the cabinets. So any ideas or suggestions would be highly appreciated.
More pics to come as the build progresses!
The build started with lots of research and with the help of this forum and similar others, I was able to put together a parts list. After 2 weeks of waiting and driving around like a maniac trying to piece things together, I was able to gather all required parts minus a 50k ohm dual gain audio pot. This can wait till I'm closer to being finished.
So far I was able to put together the power supply and test the output voltage.
Some amp and power supply components
An externally hosted image should be here but it was not working when we last tested it.
hand matching resistors
An externally hosted image should be here but it was not working when we last tested it.
one rail completed
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
both rails completed
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
testing output dc positive voltage 37.3
An externally hosted image should be here but it was not working when we last tested it.
testing output dc negative voltage -37.3
An externally hosted image should be here but it was not working when we last tested it.
My plans for the weekend are to begin the amp channels build along with customizing my aluminum enclosure for the entire setup.
I would like to hear some ideas on bookshelf speakers and a custom sub/amp. For now I'll be using Polk monitor 30 to run off the lm3886 and a self powered Onkyo sub. I plan on building the crossovers and buying separate components along with the cabinets. So any ideas or suggestions would be highly appreciated.
More pics to come as the build progresses!
I got one channel to work today, sounds really good. I threw the right channel together just for testing purposes with the minimum amount of components.
For now I got a few pics of the point to point test build on the right channel.
Small components
Chip amp complete
Powersupply filter caps
Right channel assembled for testing and tuning
For now I got a few pics of the point to point test build on the right channel.
Small components
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Chip amp complete
An externally hosted image should be here but it was not working when we last tested it.
Powersupply filter caps
An externally hosted image should be here but it was not working when we last tested it.
Right channel assembled for testing and tuning
An externally hosted image should be here but it was not working when we last tested it.
New Update...
Haven't had much time to work on the amp lately, but there's a lot of progress since last post. I was able to build and test one channel, play around with some numbers and components to get the best possible sound so here are the pics of how it currently sits...
Aluminum Case purchased for $5, a little scratched but will do. Will polish later.
Power supply attached
Power Supply wires shrink tubed
Fuse and power switch added
Heatsink attached for one channel
Left channel completed, ready to attach to heatsink
Right channel in build progress
I'm waiting on the RCA chassis mount jacks and volume control pots with knobs, once those arrive and the right channel is completed, it should be finally finished.
As far as the sound goes, it's absolutely amazing. Extremely clear and detailed highs along with tight mids and some decent bass. Can't wait to build a better pair of bookshelfs to eventually replace the Polks.
Haven't had much time to work on the amp lately, but there's a lot of progress since last post. I was able to build and test one channel, play around with some numbers and components to get the best possible sound so here are the pics of how it currently sits...
Aluminum Case purchased for $5, a little scratched but will do. Will polish later.
Power supply attached
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Power Supply wires shrink tubed
An externally hosted image should be here but it was not working when we last tested it.
Fuse and power switch added
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Heatsink attached for one channel
An externally hosted image should be here but it was not working when we last tested it.
Left channel completed, ready to attach to heatsink
An externally hosted image should be here but it was not working when we last tested it.
Right channel in build progress
An externally hosted image should be here but it was not working when we last tested it.
I'm waiting on the RCA chassis mount jacks and volume control pots with knobs, once those arrive and the right channel is completed, it should be finally finished.
As far as the sound goes, it's absolutely amazing. Extremely clear and detailed highs along with tight mids and some decent bass. Can't wait to build a better pair of bookshelfs to eventually replace the Polks.
Thanks man!
I'm in the process of designing a PCB board in Eagle for both the PSU, left and right channels. Should look much better and be assembled much faster. For my first build though, I wanted to build the entire thing from scratch, learn some things as I go and try out different configurations to get the best sound out of a specific setup.
I'm in the process of designing a PCB board in Eagle for both the PSU, left and right channels. Should look much better and be assembled much faster. For my first build though, I wanted to build the entire thing from scratch, learn some things as I go and try out different configurations to get the best sound out of a specific setup.
Another Update:
Amp completed for the most part. Been running for 3 days now and I'm absolutely addicted to the sound.
The station:
Amp:
I'm going to run it for another 2 or 3 days, then pull it out, shrink tube and organize the rest of the wiring, polish the enclosure and install the lid. I'll be also wrapping part of the enclosure in carbon fiber vinyl.
Currently I'm running Polk 30s and Polk self powered 12" sub. I'm looking for ideas for some custom speakers so if you guys have any let me know.
Amp completed for the most part. Been running for 3 days now and I'm absolutely addicted to the sound.
The station:
An externally hosted image should be here but it was not working when we last tested it.
Amp:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I'm going to run it for another 2 or 3 days, then pull it out, shrink tube and organize the rest of the wiring, polish the enclosure and install the lid. I'll be also wrapping part of the enclosure in carbon fiber vinyl.
Currently I'm running Polk 30s and Polk self powered 12" sub. I'm looking for ideas for some custom speakers so if you guys have any let me know.
Very tidy indeed mate, as someone else said it does make me feel less of a man for using a PCB. You have done a great job of thinking through where each of the components were going to fit and the need to maintain lead wires for the external connections. I just hope if you do a PCB the sound doesn't deteriorate.
Have you seen much of Peter Daniels work? He does some amazing point to point work and yours is definitely in that ball park for a first build.
Are you driving the amp straight from the soundcard?
Have you seen much of Peter Daniels work? He does some amazing point to point work and yours is definitely in that ball park for a first build.
Are you driving the amp straight from the soundcard?
I built one of Peter's amps, the 3875. I run a pair of Fostex FE127 Fonkens. I don't know what it is about this amp, but it really works well with these speakers. I've run different speakers with the amp and different amps with these speakers, but nothing does for them what the 3875 amp does.
If the characteristic that makes the Fonkens sound great is the same with the 3875 and the 3886, I would HIGHLY recommend the Fonkens. I'm sure one of the fine members on the forum can explain the characteristic I'm referring to.
Mike
If the characteristic that makes the Fonkens sound great is the same with the 3875 and the 3886, I would HIGHLY recommend the Fonkens. I'm sure one of the fine members on the forum can explain the characteristic I'm referring to.
Mike
I can! I did build one of the Peter Daniel LM3875 amp too. I know the sound of those amps, they sound really good, I used a lot capacitance on the ps boards.
Very nice job!!! I was afraid to do point to point wiring because the result would no be so nice as using boards. But, in your case it came out nice and neat. Congratulations!
Last quick update before the speaker research and build starts:
Amp as it sits now functionally completed with a few cosmetic things left to do in the nearest future
Closeup of heatsink and chip amp mounted:
Amp as it sits now functionally completed with a few cosmetic things left to do in the nearest future
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Closeup of heatsink and chip amp mounted:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Those things came pretapped on those sides so to save me some hassle I figured I'd use it that way for now. To be honest those things barely even get warm. The bottoms have thermal paste so the heat dissipates quick into the actual enclosure. By the time it starts to get really hot in the room, I'll have a new enclosure and a whole different design.
Thanks for all the comments guys!
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