LM 3886 chipamp project completed

[Anil kumar]

Hi all, finally my amp was powered few weeks back!!!
Project started in 2010 but could not complete for some reason. This cabinet is a overkill, but i wanted a neat & nice looking enclosure. This is a simple chassis using 4 aluminum panels on top , back, bottom and 2 heat sinks on the sides & enclosure feet is made of aluminum which is machined for perfect fit. Front panel is 6mm thick with countersink holes that mesh perfectly with chassis. Heat sink & front panel are milled for perfection. Did lot of running around to get the right kind of material for the project.

Thanks to siva (linuxguru) for board & components & josephjohnt for R core transformer. Special thanks to SoundsGreat for his great help right from populating the board to wiring, he has done a great job All cables are twisted & protected by heat shrink tube to reduce noises, added a EMI filter before the transformer which greatly reduced the hum. Front plate is not anodized as i have plans of some upgrade. It has done about 100 + hours of burnt in, it sounds pretty cool Sounding great on my towers.

More pictures here at my DIY EFFORTS PAGE

Heat sink after milling

Front plate being milled

Assembled heat sink

Amp in action after assembly

chassis after assembly

Mock assembly

Cabinet after powder coating

After final assembly

 

[anilva]

Amazing build quality. Looks like you had the full workshop for yourself.

Cheers.

 

[jetlag]

Hi Anil
Fantastic build. I am building one LM3886 as well, have given me some great ideas. Particularly the way you have mounted the r-core...minimalistic approach.

Later
Peace
Jetlag

 

[sjith]

aluminium, welding less assembly - good approach

 

[linuxguru]

That build is simply stunning - Congratulations!

Is there any way you can offer identical cases/panels to DIYers? Engineering drawings, e.g. as plain printable image files, would be highly welcome, too.

(The only thing I might do differently is to use CSK profile (conical head) Allen-head bolts to fasten the top panel to the side panels - with a CSK profile drilled into the top panel to the correct depth to allow flush-mounting the bolts. This is used by Cambridge Audio, but with standard philips-head screws with a CSK profile, as well as 8Audio. I'll post pics of a cloned 8Audio case (almost completed) shortly to show the idea.)

I'm also getting stainless-steel feet fabricated, but may switch to aluminium as you have done, depending on the pricing.

 

[sachu888]

Very nice:thumbsup:

Regards,
Sachin

 

[spirovious]

Very nice built,how do you define the sound?

 

[linuxguru]

FWIW, those boards are the Mauro Penasa MyRef Rev C kits (with my v1.3 PCBs) which I supplied to Anil. You can read about the MyRef at these threads at DIYAudio, including the original posts by Mauro Penasa himself:

My "audiophile" LM3886 approach - diyAudio
The new "My Ref" Rev C thread - diyAudio

An alternative design that borrows ideas from the MyRef, but with opamp and chipamp flexibility, is the MiniRef, which I designed and uploaded to DIYAudio a couple of years ago:

MiniRef Schematic and PCB layout - diyAudio

There is now interest developing in South Korea in a premium audiophile version of the MiniRef with AD797B opamps, LM1875 chipamps, and a discrete Salas shunt regulator for the opamps, which presapian @ diyaudio (who developed this tweaked version) claiming that it sounds even better than the MyRef.

 

[nraghunadh]

Looking professional and beautiful. Perfect build. :clapping: :clapping: :clapping:
I have procured all the parts except power supply board for my LM3875 build.
Got custom made (2 x 0-25v @7Amps each and 0-12v@1amp) Toroidal transformer from EMD Hyderabad. Your R-Core transformer looks EMD make, what about the power rating and pricing?

Thank you
Raghu

 

[ukjeyaraj]

Nice and clean looking build. Congratulations.

 

[vivek.saikia]

Very professional finishing for a DIY amp.

 

[tcpip]

Where did you get the R-core transformer from?

The power switch you have used is exactly the type I have been eyeing for some time. Are they easily available in India?

 

[Hiten]

Superb build Anil kumar.
Regards

 

[AmitKumar]

These pictures look great.

excellent build quality.

now you could share the listening impressions.

 

[saheb11123]

WOW!

Great metal work.
What speakers are you using them with?

 

[keith_correa]

T.H.A.T.........I.S.........S.T.U.N.N.I.N.G.!!!

Where the heck do you guys get the resources from in B'lore to do the work [cutting, milling etc.]? In Mumbai, the workshop guys will laugh me out if I ask if they can undertake something like this.

 

[josephjohnt]

Great work Anil :clapping: Hope they sound good as well.

 

[anshulkwatra]

An absolute thing of beauty and sound

 

[saheb11123]

T.H.A.T.........I.S.........S.T.U.N.N.I.N.G.!!!

Where the heck do you guys get the resources from in B'lore to do the work [cutting, milling etc.]? In Mumbai, the workshop guys will laugh me out if I ask if they can undertake something like this.

What he said applies here multiplied by 2 in kolkata.

 

[doors666]

What he said applies here multiplied by 2 in kolkata.

Its the same case here in bangalore:lol: