First Amp Build - Potentially LM3886

Good day everyone,

Pleased to be here. I built a couple of tower speakers (F6/AMT Nephila build by Wolf) a year ago and have been powering them using a very underperforming class D amp from Amazon. In recent months, the output has dramatically decreased. I think it is time to run these off of something a little more promising.

This being said, I have scoured the internet in search for a decent amplifier kit to build. I do have extensive experience with soldering and did analog circuit design years ago in school (basically too long ago for it to be super useful). So the questions I ask may not entirely make sense. Please bare with me while I catch up :)

I would prefer not to do a class A.

Here is what i've narrowed down to, unless the wealth of knowledge here pushes me in a different direction:

1. Amp board

2. Power Supply

Questions:

1. Would you recommend this amplifier?
2. What other components would you recommend to pair with it? Any specific brand of Potentiometer for volume control?
3. Will I be basically paying for the board then have to buy the components from a reputable source like Digikey?

Any ideas or recommendations are greatly welcomed and appreciated.
 
Hello,
The amplifier kit looks nice(quality pieces), the power supply does not look so good though, to power up the amplifier you just need a transformer from 220V or 110V(depends on your location) to 15-0-15V up to 28-0-28V( i use 25-0-25V to drive 8 Ohm speakers).
For the volume control, if you have the possibility use ALPS RK27 50Kx2.
Pay attention to the heat sink....that may not be included in the kit.
 

Attachments

  • alps-rk27-50kax2.jpg
    alps-rk27-50kax2.jpg
    48.8 KB · Views: 469
Hello,
The amplifier kit looks nice(quality pieces), the power supply does not look so good though, to power up the amplifier you just need a transformer from 220V or 110V(depends on your location) to 15-0-15V up to 28-0-28V( i use 25-0-25V to drive 8 Ohm speakers).
For the volume control, if you have the possibility use ALPS RK27 50Kx2.
Pay attention to the heat sink....that may not be included in the kit.

Thanks! I like that route.
 
Hello,
The amplifier kit looks nice(quality pieces), the power supply does not look so good though, to power up the amplifier you just need a transformer from 220V or 110V(depends on your location) to 15-0-15V up to 28-0-28V( i use 25-0-25V to drive 8 Ohm speakers).
For the volume control, if you have the possibility use ALPS RK27 50Kx2.
Pay attention to the heat sink....that may not be included in the kit.

Hey, with the RCA input terminals, do you recommend designing a load match circuit? Is that something which is built in that amp already?

I am trying to pick out a case and RCA input terminals.
 
@mrgarison - Which is the signal source? I use a desktop PC as signal source( 24bit, 192000Hz), my RCA input terminals are connected to 50K volume potentiometer than to the signal input of the amplifier... and it works just fine. I have to mention tough, that i am using a different LM3886 kit...more simple than the one you want to use... XY LM3886 kit bought from ebay. In my point of view the reproduced sound is quite spectacular...but i am not a musician...i am just comparing the sound to the other amplifiers that i have build over time and of course i must be subjective. Anyhow every solution is a compromise.


@knauf1919- Thank you for your kind remark, maybe you have higher experience in building this kind of amplifiers( Chip Amps), this way, maybe, you can give us some better ideas. Thank you.


Please excuse any errors, English is not my native language.
 

Attachments

  • 20190111_215630.jpg
    20190111_215630.jpg
    80.6 KB · Views: 397
  • 20190111_215729.jpg
    20190111_215729.jpg
    91.7 KB · Views: 405
  • s-l1600.jpg
    s-l1600.jpg
    106.8 KB · Views: 399
@mrgarison - Which is the signal source? I use a desktop PC as signal source( 24bit, 192000Hz), my RCA input terminals are connected to 50K volume potentiometer than to the signal input of the amplifier... and it works just fine. I have to mention tough, that i am using a different LM3886 kit...more simple than the one you want to use... XY LM3886 kit bought from ebay. In my point of view the reproduced sound is quite spectacular...but i am not a musician...i am just comparing the sound to the other amplifiers that i have build over time and of course i must be subjective. Anyhow every solution is a compromise.


@knauf1919- Thank you for your kind remark, maybe you have higher experience in building this kind of amplifiers( Chip Amps), this way, maybe, you can give us some better ideas. Thank you.


Please excuse any errors, English is not my native language.

Thanks for that input Mishu, I really like your simple and effective setup. Can you confirm the amplifier I chose doesn't need the Capacitor filter you have used before the Toroidal? Or should I still use one?

What kind of wood did you use to build yours?

To answer your question, the source will be PC/Aux.
 

tomchr

Member
Paid Member
2009-02-11 12:58 am
Calgary
www.neurochrome.com
Yeah. Shy away from eBay unless you're just looking to solder some stuff together. I reviewed one of the better eBay boards here: XY LM3886 Kit Review & Measurements

I suspected the LM3886 was fake and contacted some connections at TI to have it analyzed. TI confirmed that it was indeed not a TI product, though it did appear to contain an LM3886 die as I recall. Whether it was a test reject or some other floor-sweep that made it out of the fab somehow is unknown.

If you're after performance, I suggest my Modulus-86. It uses error correction to drive the distortion of the LM3886 down into the abyss. The result is a marked improvement on the LM3886 itself.
On the surface, the Modulus-86 may seem more expensive than a 'naked' LM3886, but in reality the Modulus-86 adds maybe 5-10% to the total project cost compared to the 'naked' LM3886. The vast majority of the build cost is the chassis, heat sinks, power supply, etc.

Tom
 
Yeah. Shy away from eBay unless you're just looking to solder some stuff together. I reviewed one of the better eBay boards here: XY LM3886 Kit Review & Measurements

I suspected the LM3886 was fake and contacted some connections at TI to have it analyzed. TI confirmed that it was indeed not a TI product, though it did appear to contain an LM3886 die as I recall. Whether it was a test reject or some other floor-sweep that made it out of the fab somehow is unknown.

If you're after performance, I suggest my Modulus-86. It uses error correction to drive the distortion of the LM3886 down into the abyss. The result is a marked improvement on the LM3886 itself.
On the surface, the Modulus-86 may seem more expensive than a 'naked' LM3886, but in reality the Modulus-86 adds maybe 5-10% to the total project cost compared to the 'naked' LM3886. The vast majority of the build cost is the chassis, heat sinks, power supply, etc.

Tom

Hey Tom, very nice work. Your board is satisfying to look at. Thanks for sharing your site, now I have another great option!
 

invaderzim

Member
2015-10-07 4:07 am
The from China amp kits and assembled boards tend to make me wonder if they are genuine parts or if I should swap them out. For me that takes away some of the good feeling when the build is complete.

As far as satisfying builds go the LM3886DR that I built some time back has to be near the top so I'd imagine the modu-86 is even better.

Having built a several amp boards I have to say going with a well known design with great support is a big plus. There is a lot to be said for not having to track down hard to find discontinued components or guess if something will be 'okay' to use instead in the build. Being able to just email a question or ask it on here is priceless; especially with a first build.
 
FWIW, I’ve build dozens of kits of various types over my hobby career, including several bare bones chip amp offerings, but my only experience with the 3886 was with Tom’s designs - in fact I’ve heard a total of 4 models. Even the most basic LM3886 “done right” was quite a decent sounding piece, but the composite Modulus series are something dry special. My main amp in upstairs system is the Modulus286.
If nothing else, a deep dive into his full set of documentation on the subject would be educational.
 
Last edited:
Good day everyone,

Pleased to be here. I built a couple of tower speakers (F6/AMT Nephila build by Wolf) a year ago and have been powering them using a very underperforming class D amp from Amazon. In recent months, the output has dramatically decreased. I think it is time to run these off of something a little more promising.

Nephila | Parts Express Project Gallery

attachment.php


LM3886 amplifier.

With only one LM3886 by channel, better loudspeakers of 8 Ohms like Nephila. Then you can build a more unexpensive kit.

85 dB/W/m at 8 Ohms.

Pro-Audio and Lighting Calculators : dBs, time, Hz, DMX ...

3 meters, random phase, 50 watts -> 95.5 dBSPL. No problema with great recordings and high DR. With films better 100 dBSPL -> you need more than 2 LM3886 by channel or other kind of amplifier.
 

Attachments

  • Nephila-loudspeaker-graphs.png
    Nephila-loudspeaker-graphs.png
    105.2 KB · Views: 399
Last edited:
FWIW, all of the Neurochrome 3886 amps I’ve heard we’re powered by SMPS, as are the DIY Audio store ACA - which receive a lot of love here. Of course all power supplies need to be used within their design envelopes, and as with linear supplies not all SMPS are created equal, but today’s better quality products offer a lot of advantages.