I would ask Tom at Neurochrome if he maybe has the LM3886 and controlling opamp left in stock.
These chips are pretty hard to find these days.
You may simply remove a 3886 from a China / Ebay PCB. The opamp may be available in SMD packages that need to be "adjusted" for regular use by means of some kind of breakout board / adapter. Interestingly, even the opposite (DIP to SMD) seems to exist !!
https://sg.element14.com/productimages/standard/en_GB/2476033-40.jpg
https://www.audiophonics.fr/21229-l...ring-on-soic-8-printed-circuit-board-unit.jpg
https://sg.element14.com/productimages/standard/en_GB/2476033-40.jpg
https://www.audiophonics.fr/21229-l...ring-on-soic-8-printed-circuit-board-unit.jpg
What is the difference between Toms Mod-86 and the cheap kits from China ? https://www.ebay.com/itm/284013335249
There seems to be different versions of LM3886, LM3886T, LM3886TF ?
There seems to be different versions of LM3886, LM3886T, LM3886TF ?
I think you ordered a bare board, so you still need to get:
- all components
- a real LM3886 (not easy)
- power supply components and board
- a power transformer
- a suitable chassis (which you will need to drill, label, maybe paint) to house everything
- some kind of enclosure
- a Bluetooth module
- something to feed it, maybe down-regulating a power amp rail, maybe a separate supply
and of course you have to build the whole thing.
Do you have some experience DIYing?
Not a too difficult project for somebody who already built a couple projects, maybe not the best to cut your teeth on.
Personally I would have searched for a ready built amplifier which also incorporated a built-in BT module, straight from the cradle, and which was accompanied by a suitable power supply, even better if already built inside a cabinet as a plug-in solution.
Don´t obsess with power amp specs: audiophile quality, vanishing distortion, is of course good any day of the week, but as mentioned above, even 1% distortion pales compare to the many % points of any normal speaker .... and in any case most power amps out there are better than that.
Yes, I got some soldering DYI experience. I think I will get a ready-built amp with BT too - I like Aiyima A07, but Aiyima A300 with BT got some really bad reviews. Is SMSL SA300 any good ? Any suggestions ?
I heard that some of the cheap class-d amps have THD like 10% when playing loud ?
I was actually thinking about using the mod-86 for my project, not just for testing, but there I need an mono amp with BT with a very small footprint and the mod-86 with everything included takes up a lot of space, I think.
I heard that some of the cheap class-d amps have THD like 10% when playing loud ?
I was actually thinking about using the mod-86 for my project, not just for testing, but there I need an mono amp with BT with a very small footprint and the mod-86 with everything included takes up a lot of space, I think.
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I think Tom has a composite amplifier which, in my opinion, results in excellent error correction over the existing LM3886, mainly in terms of PSRR (important), THD/IMD (less noticeable) etc.
Of all the LM3886s, I recommend getting the plastic (all black) version shown in the link that you cited, as your operating power, at best, is likely to be modest. If you happen to get an Ebay / Alibaba kit, you could take whatever you want (resistors, capacitors etc. ) and sell or gift the PCBs to encourage someone else who is a beginner.
Since you're into speaker testing, I suggest that you avoid using interfaces with inherent transmission delays, as is the case with Bluetooth etc. and try to directly wire your input into the amplifier (preferably) through a follower stage, so as to get best results during testing. Remember that test rigs need to be robust, predictable and dependable, rather than being fancy (shiny cabinet, USB, wireless etc.)
EDIT: Note that the bare LM3886 (Ebay) should also suffice for your purpose of speaker testing.
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Thanks. You are right. I got a little sidetracked with the bluetooth. Guess Aiyima A07 would be fine for testing
I like using bluetooth and turning everything max and playing my home built 3-way speaker loud. Currently I only have a small Aiyima TPA3116 100w mono bluetooth amplifier board, that probably generates 40-50w 4ohm with 24V 6A. When setting the phone volume to max, the amp board is already max (no volume control), the speaker distorts in the midrange (only). It does not when playing not so loud. Does this distortion most likely come from the phone, the amp or the driver ?
I know I need a bigger amp for testing and maybe also for normal playing. But with a bigger amp, how should I then limit how high you can safely play the speakers with all kinds of different music (and phones) ? Does everybody turn the phone volume to max if they can ?
I know I need a bigger amp for testing and maybe also for normal playing. But with a bigger amp, how should I then limit how high you can safely play the speakers with all kinds of different music (and phones) ? Does everybody turn the phone volume to max if they can ?
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You do NOT need a bigger amp for testing .
As said above (PRR or Rayma? .... both sensible experienced guys), you test and measure at about 1W RMS and listen to sound quality at 10/12W, more than enough.
Reserve 100-200W for Saturday Night Disco parties where DJ will clip the amp continuously no matter what (so easily 20 to 40% disortion) , he will burn voice coils, at last the tweeter ones and anyway Police will stop the "testing" in less than an hour because of Neighbours complaints.
TPA3116 is a GOOD chipamp, not sure how would Aiyima manage to make a BAD one since easiest is to follow datasheet suggestions and those are all good, by definition.
Common answer "I don´t like it" typically comes from people who also say : "yes, I drive a rust bucket shot engine 1972 clunker BUT MY OTHER CAR IS A BMW"
Yea, sure.
As said above (PRR or Rayma? .... both sensible experienced guys), you test and measure at about 1W RMS and listen to sound quality at 10/12W, more than enough.
Reserve 100-200W for Saturday Night Disco parties where DJ will clip the amp continuously no matter what (so easily 20 to 40% disortion) , he will burn voice coils, at last the tweeter ones and anyway Police will stop the "testing" in less than an hour because of Neighbours complaints.
TPA3116 is a GOOD chipamp, not sure how would Aiyima manage to make a BAD one since easiest is to follow datasheet suggestions and those are all good, by definition.
Common answer "I don´t like it" typically comes from people who also say : "yes, I drive a rust bucket shot engine 1972 clunker BUT MY OTHER CAR IS A BMW"
Yea, sure.
Thanks. But I don't understand how I can measure distortion from the drivers at high levels this way ?
Newvirus2008 talks about an issue which happen when you drive your loudspeakers at high power ( for long period): you make a lot of heat within your driver, specifications change ( T/S parameters) and as outcome you'll have less output level than you could expect from theory, you experience 'power compression'.
99% of drivers are subject to it. Some drivers are designed to lessen or take care of it in a 'gentle' manner ( these are usually live or P.A. oriented drivers).
At 200w you'll likely be able to test it with most drivers ( especially 'hifi' oriented).
So if only for testing purpose 200w is questionable to be of use ( it could be if you want to characterise the dynamic behavior of a driver you plan to deliver high spl but few amateur designers bothers, and for domestical use something in the 30/60w vicinity is ample for this kind of test (15 to 18db dynamic range above rms ( average) level).
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