My affordable LM3886 DIY amplifier.

[Hiten]

OK will see how I can manage this in my amp.

 

[Outofphase]

nice build

 

[Hiten]

keith,
I checked speaker terminals. Little distance constrained for fixing capacitor. As 1 cm cap leads are mentioned in Bonsai article. However I checked with my mobile by calling and turning amplifier volume full (No sound playing) and moved mobile towards speaker termina, input sockets, speaker wires, interconnect wires. There was no interference. So I guess probably OK (not sure though)
I also checked various input/output ground . With no interconnect my cd player shows short on two L & R output (RCA sockets) my amp RCA input ground shows open. means they are not connected. But since CD player are short you were right in saying only one cap would do.. Now it seems the 1nf two caps will be 2nf (Parallel). But i guess I should take comfort in knowing that this 1nf value is not severely important as I have read discussion about various values and various types of caps in this position. Since I am not getting any noise will as of now keep as it is. But I will surely be considering your input in next project.
regds

 

[jmascreen]

Classy look and well executed waiting for them to land in "For Sale"

 

[Hari Iyer]

Nice built. But I thought you were building a tube amplifier -

 

[Hiten]

Classy look and well executed waiting for them to land in "For Sale"

Would not mind barter too. Some nice VFM midranges, Dome tweeters or 60/100 watts amp boards/kits. Good PS with speaker protection etc.

Nice built. But I thought you were building a tube amplifier -

Bhai,
It was abandoned. I mentioned few time in the forum. All parts were also sold in forum itself. This was good few months back.

Regards

 

[HormusPeston]

Great job! Looks very clean and I'm sure it sounds great. I quite like the sound of LM chip amps and also the venerable STK series; I like, even more, the sanity they bring to the DIY world. Or perhaps I should say that they keep us "grounded."
I remember that thread on diyAudio. I built an SX amp and found it to be quite nice--sounds like a JLH. (The sx is now working hard playing jazz at a friend's house.) Bonsai's PDF on grounding is straightforward and clean, and even I can understand the electrical theory behind his grounding scheme. I cannot say that I fully understand everything Andrew says...
Cheers,
~hp

 

[adityamody]

Hi Hiten,

Liked your cabinet, need help in getting one for the amp I’m building.

 

[Hiten]

Hello aditya,
the cabinet is from Gtech Audio. Tamil Nadu as mentioned in first post.
Regards

 

[ssf]

.

 

[sdk]

Only one cap is needed - not one per channel. You bond the grounds from each channel together and then connect it to the chassis via one 1nf cap.

In Andrew's pdf - Page 51, the 3rd bullet from top.

Is there a link to download this famed pdf or even a search string for Google?

 

[Hiten]

Is there a link to download this famed pdf or even a search string for Google?

The link is in post #15 of this thread. Bonsai (DiyAUdio) has wriiten few more articles/blogs on his website which has link in his Diyaudio account.
Regards

 

[adityamody]

Hello aditya,
the cabinet is from Gtech Audio. Tamil Nadu as mentioned in first post.
Regards

Hi Hiten,
Thank you..
I re-read your thread and also tried to communicate with him but was difficult as I needed the back panel to be blank so that I could do the 4-way stereo RCA and one stereo speaker along with the IEC power socket. Probably I will order it and manage something on my own or get a custom done.

 

[Hiten]

Aditya,
The original back panel had couple of RCA socket holes. The single cut on back panel you see is made by me. This being power amplifier I only required a pair RCA input and speaker connectors.

 

[adityamody]

Aditya,
The original back panel had couple of RCA socket holes. The single cut on back panel you see is made by me. This being power amplifier I only required a pair RCA input and speaker connectors.

thank you very much for this post else I surely would be hunting for a cabinet.

I have a slightly different application as I want it like a stereo receiver and I m not using the Chinese "mp3 bricks" for it. So, therefore, need a few extra things. also will be using Rasberry pi as a streamer for input and input from tv ( Firestick ).

 

[Hiten]

OK. Do share your build in the forum.
Regards.

 

[adityamody]

My amp currently is LM3886 my ref revA, I am happy with it and I am sourcing audio through Rpi + higiberry Dac+ Adc pro

 

[adityamody]

 

[Hiten]

Nice build.
regards

 

[viveshsahu]

Hello folks,
This is my fun, getting hands dirty DIY LM3886 amplifier. It was started during lockdown, as I had nothing to do. But later got busy so finished it when time permitted. I have no knowledge of proper electronics so cant answer technical questions. But ask me other things. As some of you know I just build to listen to the sound and move on. So this amplifier will be on sale soon to fund my next DIY project. The amp works perfectly and sounds good. LM3886 is probably last class AB high quality IC. Specifications are great for 40 watts in to 8 ohms. My main goal was to build as cheap as possible and had budget of 5K which exceeded . But it is built with love.

Some details...
This LM3886 chinese module and most parts are from GTech audio (Tamil Nadu). Some parts they couriered by air which was not necessary. Overall good experience with Gtech Audio. Smaller chassis was chosen to save money so amp is little bit congested inside. And I misjudged speaker terminal space from modules. But it is manageable. There are details after some picture and cost of the project, which probably will be helpful to new diyers like me. Audio CD will give you some perspective.

View attachment 64718

View attachment 64719

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View attachment 64721
(1) Power on light and wire routing aluminum clips. (2) Extension shaft from robotics project (3) Mains Terminal to fuses and transformer from AC mains. There is plastic film below PS boards. (4) 1.5A fuse for each channel. Earlier I had two pole on/off switch but it broke so am using single pole switch for live wire. Separate fuse on two PS board. There is also an extra third main fuse.

View attachment 64722
(5) Capacitor from Input ground to chassis to attenuate RF (6) Grommet from CD player mechanism (mains in has turntable grommet (7) PS 0v two wires and mains earth wire grounded to Amplifier main chassis (8) Four 4700uf Caps. per channel. Silly me I thought caps would get hot so removed original sleeves then put on new one realizing the outer capacitor case will be carrying voltages.

View attachment 64723

(Top Left) Power on light made from LED TV backlight bulb plastic. (Top Right) 10 K volume pot made fake logarithmic with a resistor. (Bottom Left) Speaker Terminals. (Bottom Right) Aluminum piece is on IC just for countersunk hole for screw.

Approximate build cost.
View attachment 64726



Thanks for watching. Suggestions welcome and will be highly appreciated.
Regards

looks great from inside and outside. specilaly the inside layout looks like done by professionals. How you managed to do so? Are you academically qualified?