First Amp Build - Potentially LM3886

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mrgarison

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Joined 2018
maty tinman said:
Nephila | Parts Express Project Gallery

813887d1580749327-amp-build-potentially-lm3886-nephila-loudspeaker-graphs-png


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.
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I appreciate this input. I may not fully understand. Please confirm this: the Nephila kit requires an amplifier capable of delivering 95 WRMS per tower, correct? (AMT=50wrms, F6=45wrms). If that is the case, I get your point. I also like the idea of a Class D. Although, it appears Class D is somewhat of a debated route. Do you have experience in the digital life?
 
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mrgarison

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Joined 2018
invaderzim said:
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.
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Top notch advice. Thanks Zim. I've been there before and value support on the user end. Something I will consider.
 
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mrgarison

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chrisb said:
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.
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Thanks for the direction Chris. I just looked at Tom's comparison of the eBay XYLM3886 vs his one. Educational read
 
maty tinman

maty tinman

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Joined 2012
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I listen to very good recordings with high / very high DR. KEF Q100 5.25" coaxials, with true 85 dB and about 5 Ohms (KEF says 86 dB and... 8 Ohms :( ).

Calcs are made with 8 Ohms. Then with 4 Ohms, double watts. 4 Ohms, better with two LM3886 by channel.

To 3 meters I want at least an amplifier with 80 watts at 8 Ohms, 0.1% THD, and about 120 watts or more at 4 Ohms. These coaxials love watts (KEF LS50 more!, with true 83 dB more watts!).

Of course, it is better that the amplifier never leave its comfort zone even at maximum demand.
 
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maxhifi

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The LM3886 is around the most capable chip amp presently being made. If you want more power, the options are either parallel BTL LM3886, a discrete amplifier, or class D. The most straightforward option for good sounding high power would be a regular complementary symmetry class AB discrete transistor amplifier. There are lots of options out there.
 
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mrgarison

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Joined 2018
maxhifi said:
The LM3886 is around the most capable chip amp presently being made. If you want more power, the options are either parallel BTL LM3886, a discrete amplifier, or class D. The most straightforward option for good sounding high power would be a regular complementary symmetry class AB discrete transistor amplifier. There are lots of options out there.
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Thanks Max, i'll do some more research. I did come across two items. 1. PA100 DIY 2x LM3886 in parallel gainclone audio amplifier and 2. http://www.ti.com/tool/TPA3221EVM?jktype=tools_software

I know those are two entirely different worlds. I do like the idea of a class D for the efficiency, however, I would enjoy the learning aspect of the Class AB.

Going through some very old lecture notes now. Had a few courses on Amplifier design. We moved quickly through it to take on RF circuits.
 
Mark Johnson

Mark Johnson

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maxhifi

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Joined 2005
Mark Johnson said:
You could consider this diyAudio Store offering

The diyAB "Honey Badger" Class AB Power Amp - 150W/Channel – diyAudio Store

Constructing one of these will be about five times more difficult & complex than the GT-102K with LM3886. But if you are willing to take the extra risk, and spend the extra time and money on your first amp build, it does have more output power.

_
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Wow nice amplifier, that one is going go have a lot of current delivery with all those output devices! I think though that it is a very ambitious first project, I would suggest to build a few small kits and practice component identification and soldering before moving to a brute like that... after all, in a direct coupled amp, one wrong move can instantly kill all the transistors in an channel at once.
 
Kokanee

Kokanee

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My 2Cents

Check out the chip amp section and the gallery to see what brands or manufacturer's people have built. If you have problems building, it is nice to know that someone on the forum has probably built one also and can help out.

Mark Johnson just had a GB for a variety of boards. You may be able to get some off one of the members who bought.

check tomchr's website. Has some great kits

Check the The My_Ref Freman edition.

Check if Audio Sector is still supply kits

Have fun building whatever you choose.:) I still have some Audio Sector kits to build, plus the Mark Johnson offering, Need to find some time.:D
 
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mrgarison

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Joined 2018
Thanks guys,

That Honey Badger looks very appealing. The cost is my only concern. From what I can tell, the total build with an enclosure could be around 800-1000$ correct?

I've built an AM/FM radio in the past and would consider my soldering skills to be advanced for through-hole and intermediate for SMD.

Maxhifi, your concerns are not unwarranted. On the functional side of things, mistakes can happen ;)

Space is a factor which is also giving me a headache.... man that TPA3255EVM is really looking good right now.
 
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NealJ

Member
Joined 2017
mrgarison said:
Thanks guys,

That Honey Badger looks very appealing. The cost is my only concern. From what I can tell, the total build with an enclosure could be around 800-1000$ correct?
Space is a factor which is also giving me a headache.... man that TPA3255EVM is really looking good right now.
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An LM3886 based amp would definitely make a nice starter, cheap and compact.

A member here, 00940, designed a LM3886 board that people can get manufactured for themselves - it costs about £6 or so for five boards and no expertise is needed, you just upload a zip file to the manufacturers site.

You could get 5 amp boards and 5 PSU boards for about £10 or so. Delivery takes about 2 weeks.
 
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