Need Help with 3 way LM3886 Gainclone active amplifier

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Naresh Electronics is the most reliable source for Neutrik original products. You need a 4-pole Speakon cable plug and chassis socket per mono channel.
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Ahh! I went there last some 18 years ago ( when I was not home bound ) I guess. The name was Naresh Radio then I guess. Is it in Madan street ? I need the specific address so that I can send someone to buy it for me.

Thank you :)
 
.................. pro audio drivers have special needs when used at home, suggest you check on the speaker forums before purchasing.

Sir, you hit the right spot.

I earnestly need basic guidance with how to build a speaker enclosure with this system.
Kindly help me with speaker brand, enclosure size, cabinet design etc. ... in short, everything. I want to make a new set of floor standers.

My listening room is some 10ft X 14ft.
 
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Ahh! I went there last some 18 years ago ( when I was not home bound ) I guess. The name was Naresh Radio then I guess. Is it in Madan street ? I need the specific address so that I can send someone to buy it for me.

Thank you :)

It's still Naresh Radio, and unfortunately I do not have the address, just the location. It is not on Madan street but inside CC. They have about 4 branches spread all over CC, this is the one inside the old market. You or your associate will have to ask around a bit.

Re your speakers - there is a speaker forum where you can post a new thread for very helpful information from the nice folk here. I would use a Eminence Alpha or two for the bass and a Beta 10Cx or 12Cx coaxial + PSD series compression driver for the mid and high, you can expect to spend about 18k in local currency on a full stereo set of drivers, not sure about what happened to driver costs after the dollar went up.

Beware that your cabinet will become humungous. Pro drivers need much larger boxes (and larger rooms) than equivalent 'Home' drivers, do not have as much LF extension (but better power handling and sensitivity). Also the smaller 6-8" drivers are purpose-built midranges, with zero LF capability. You will be able to find the driver parameters on the Eminence website and should use WinISD to simulate a box. Result is not 100% accurate but is a good start to working out the size you need.

On the plus side, you can be assured that the 3886 and a bunch of pro drivers will be enough to blow your ears out in a typical home listening environment. You can also experiment with crossover points - some compression drivers can handle the expected 20W peak power down to 1KHz.
 
Som,
Do you really need to use pro drivers? How big is your room? (or your neighbourhood, for that matter?) Is the room big enough for the huge boxes you will need?

Normal 87 - 90 dB/W domestic drivers will make your eardrums meet in the middle of your head, plus they are more sensitive and better bass extension.
 
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^^There is a sourcing issue with hifi drivers in India. They are simply not available, one has to import everything and pay through the nose for shipping and customs.

Pro drivers, OTOH, are easily and widely available, very often cheaper than US prices because they are brought in factory direct - Taiwan, China or the other Far East countries where they are made. eg a Eminence Lab 12 costs about 10% less in India after taxes, than the ex-stock price on a big US site.

This basically a demand-supply issue. Sometimes, Indian DIYers will get together for group buying, but there is no off-the-shelf availability of anything of reasonable quality.

We do have one manufacturer in India, Peerless India, which is an offshoot of an old licensing arrangement with the Peerless/Vifa of old. Some of their drivers are here: Peerless Fabrikkerne Not excellent, but usable, and with somewhat known parameters. tcpip on this forum has documented a project using their drivers here: The Asawari | dhandanought.org/tcpip

For reference, $1 (US) = INR 60.
 
...................................Beware that your cabinet will become humungous. Pro drivers need much larger boxes (and larger rooms) than equivalent 'Home' drivers, .........................
Thank you for the reply.
That's a real problem then Sir.
My listening room cum my electronics junkyard is very small. :)
Not much space is left there.

I am happy with the pristine performance of present my DIY floor standers. But I have no idea whether they are fully optimized or I can get even better than the best sound from them. I am a complete noob there.

I need to learn the speaker enclosure building now.

But I didn't want to start another thread for that.
I just wanted to make this an exhaustive resource for the fellows/ new comers who like to follow/build the same LM3886 project e.g.
1. Preamp,
2. Power amp,
3. Grounding ,
4. 3 way Active X-over,
5. and last but not the least Speaker Enclosure building.

I wanted to update and illustrate every detail of my build in Post #1 after the completion of the project.

Dear Moderators, kindly suggest , should I start another thread for this speaker enclosure building or I can carry on asking help here?

Thank you.
 
Finally finishing reading out the whole article, And I remembered had ever reading that sb. takes 400 grands to build up 300W LM3886 amps by germany. And the caps is 47,000 uf made by SPRAGUE as pool to supply sufficent current for the output, meantime to balance the voltage of power supply. The disadvantage of which is the requirement for the fuse. One channel for a pair of LM3886 is about 3A and U can calculate it's capacity of the toroidal transformer should be much bigger than 200VA.
What I am worried about is it cann't hold it when clock is ticking.
 
Som,
Do you really need to use pro drivers? How big is your room? (or your neighbourhood, for that matter?) Is the room big enough for the huge boxes you will need?

Normal 87 - 90 dB/W domestic drivers will make your eardrums meet in the middle of your head, plus they are more sensitive and better bass extension.

Sir, I think you've pointed out a very pragmatic concern.
Neighbourhood is a thing to consider too.

My room is very small and sound is already surprisingly lovely and "big" with very deep Bass with delicate details. The sound stage/ stereo image is just amazing.
Also I am going to add an Equalizer very soon.


So I guess I will use Domestic Drivers.

At present I am using 6.5'' Woofers, 4'' Midranges, and 2'' tweeters ( a mix of local brand and Chinese one ) in the Floor standers.
I placed the 3.5'' Bass-port in the speaker enclosure, with a rough guess, to extend the bass response, studying some floor stander designs on the net.
No math done yet. I just used some left over half inch plywood at home to make the enclosure.

But still, bass response of the floor stander is identical or sometimes better than a "technically designed" bought two way system with 8'' woofer and 3'' tweeter. I can confirm that.

So all, kindly guide me to improvise on the design. :)
Thank you. :)
 
^^There is a sourcing issue with hifi drivers in India. They are simply not available, .......................We do have one manufacturer in India, Peerless India, which is an offshoot of an old licensing arrangement with the Peerless/Vifa of old. Some of their drivers are here: Peerless Fabrikkerne Not excellent, but usable, and with somewhat known parameters. tcpip on this forum has documented a project using their drivers here: The Asawari | dhandanought.org/tcpip

For reference, $1 (US) = INR 60.

Thank you sir for this valuable information. I have checked out their site. Price is reasonable for my financial credential as it seems.

Are they available locally at CC? If yes could you please tell me the name of the shop?
Eagerly awaiting your reply.
 
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No. There are some Peerless drivers available in CC but not these ones, and not in any certain quantity.

That site is the only one where those drivers are available, and you have to order directly with them. Fair warning - I have neither used them nor am associated with them, so any risk you take in transacting with them, is totally yours. Also, they are dealers, not the manufacturers.

Good Luck.
 
No. There are some Peerless drivers available in CC but not these ones, and not in any certain quantity.

That site is the only one where those drivers are available, and you have to order directly with them. Fair warning - I have neither used them nor am associated with them, so any risk you take in transacting with them, is totally yours. Also, they are dealers, not the manufacturers.

Good Luck.

I understand. Thank you Sir.
 
To adjust signal levels, download a white noise signal and adjust till the mid, high and low are playing at approximately the same level, it will be closer than your ear. Use pink noise to test whether you got the result correctly. White noise has equal power in each octave range, and pink tapers it at 6dB/octave, more representative of normal music (not Indian music, that's more like white noise with bass boost).

Keep levels very low when playing white noise.

Sir, I tried to follow your method by downloading both white and pink noise files and got good result with various Genres e.g. Jazz, Blues, Rock, Pop etc. ( Player Source: audio CDs and Youtube in HD )
Thank you really for the great tip.

But not all Indian music gave the same satisfactory output.

Fortunately the Low, Mid and High X-Over controls in the front panel are offering great scope to fine tune and optimize the output on the fly.
 
It seems I need even bigger heat sink and at least two fans to absorb the generated heat. :(

The heat sink is very hot when the ceiling fan is off.

I found the Apex Fan controller Circuit here in the forum. But I am yet to make it.
http://www.diyaudio.com/forums/analog-line-level/167363-mic-line-eq-preamps-39.html#post3435753
I am not very sure about the placement of the 10k NTC. Where to mount it in the cabinet?
I never worked with NTC earlier. So kindly help me.


So before I do that,
could anyone suggest a good fan controller circuit please or is this okay to use?
 
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That sink is enough for your amp. It will get hot, but you should be fine. I have a sink exactly like that with 1x LM3886, 2x OPA549 and 2x LM1875 mounted on it and it is fine - the temps stay stable around 60-65 degrees. That, btw, is burning hot to the touch, it's like dipping your hand in a cup of hot coffee about a minute or two after it is prepared. You have 3 chips to each sink and it works quite well as the heatload is pretty low.

Re your music selection - Indian music, for the most part is recorded and mixed by rank amateurs with absolutely no taste and no sense of balance. It has too much treble and the bass cuts abruptly at 60Hz, which means a properly balanced system sounds quite bad when playing it back. I wouldn't use it to calibrate a map, let alone a music system.
 
That sink is enough for your amp. .......... You have 3 chips to each sink and it works quite well as the heatload is pretty low.
Wow!
Thank you sir for a very experienced and very well explained reply.
LM3886 has a thermal shutdown feature integrated too I guess. So they are safe after I read your reply, I think.

So I won't make the fan controller. This will definitely save me some money.

...........Indian music, for the most part is recorded and mixed by rank amateurs with absolutely no taste and no sense of balance. It has too much treble and the bass cuts abruptly at 60Hz, which means a properly balanced system sounds quite bad when playing it back. I wouldn't use it to calibrate a map, let alone a music system.

This is true again. Many Indian so called professional recordings seriously lack dynamic sound stage as I personally found playing around with professional branded system.
Earlier in my TDA2050 Tri-amped system, the X-over controls were mounted externally on the front panel too. And because of that, youtube in HD sounded unprecedentedly great as I used to balance/compensate the poor recordings on the fly as and when required to suit my taste.

So here is my plan now. I will mark three spots calibrating with white and pink noise for the X-over controls for good professional recordings so that I can revert back to the setting easily.




I have some more important questions.

Can I make a wall mounted speaker enclosure for this system ( as this will clear some more carpet area in my small room) ?
How do the wall mounted speakers enclosures perform in Hi-Fidelity system?
Is there any good wall mounted design/plan available?
 
Update: A thing happened today.
The 0 volt wire from the PSU to the centre tap of a transformer was disconnected due to an earlier bad solder while I was messing with other part of the system.
I didn't realize that until suddenly I found one of the channels was slightly distorted.

So one channel was receiving only + and - voltage and no 0v for some more than 10mins!
But fortunately nothing is burnt.

Really LM3886 is a great chip.
 
Wow!

<snipped>

Can I make a wall mounted speaker enclosure for this system ( as this will clear some more carpet area in my small room) ?
How do the wall mounted speakers enclosures perform in Hi-Fidelity system?
Is there any good wall mounted design/plan available?

Speaker placement guidelines that I have seen lead me to believe that wall mounting would be less than optimal, since the speakers should usually be well away from every wall.

Room Acoustics

Optimizing the Sound of Your Room | Articles | Polk Audio
 
Speaker placement guidelines that I have seen lead me to believe that wall mounting would be less than optimal, since the speakers should usually be well away from every wall.

Room Acoustics

Optimizing the Sound of Your Room | Articles | Polk Audio

I thank you really so much sir.
Very useful resource, just what I needed.

I have another question.

The size of my woofer is 6.5'', midrange is 4'', tweeter is 2''.
Is there any ready-to-build, free speaker enclosure design/plan for a hobbyist?

Crossover level adjustment is not a problem for me as I am using a 3 way Active X-over. And with LM3886 amp the bass response is already awesome.

I just need a very small 3 way speaker cabinet design/plan.
If you could help me with that, it would be really great.
 
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