LM3886 Schematics + PCB

[Boscoe]

This design doesn't have a top layer I believe.

 

[ariyanto]

This design doesn't have a top layer I believe.

Possible that there is no...........

 

[apexaudio]

sorry less thorough in reading??? if the top layer can be displayed mr?

There is no top layer, it's single side pcb.

 

[ariyanto]

There is no top layer, it's single side pcb.

Ooooooo That's it mr??

 

[GloBug]

That's it!

Finally got away from SS, now I kinda want to try it as a guitar amp, now that I have tubed gear.

Maybe Apexaudio could start an instrument chipamp thread. Maybe even a higher wattage version like parallel LM4780's etc.

I would love to bring a 100W amp the size of a large sandwich to the jam spot.

 

[madtecchy]

Hi globug.

i think you will need a class d amplifier to get it as small as a large sandwich as not much heatsinking is required..

best regards Ian

 

[GloBug]

I'm a pig. lol

Something to look into, thanks.

 

[yugaaa]

Tried the circuit . I am happy with the result , though i find that the volume level is not good enough . Dosent sound like a 60w amp . Does the circuit need a pre amp ? I connected it directly to a mobile headphone out . sounds like a 5 watt amplifier

 

[GloBug]

Try it with another source, it should be louder then that.

Maybe you got a fake chip. Where did you buy it?

 

[AndrewT]

Measure the output of your

mobile headphone out

Tell us the gain of your 3886 amplifier.

Go read system gain article.

 

[apexaudio]

Tried the circuit . I am happy with the result , though i find that the volume level is not good enough . Dosent sound like a 60w amp . Does the circuit need a pre amp ? I connected it directly to a mobile headphone out . sounds like a 5 watt amplifier

Increase feedback resistor 15k to 33k for increase gain.

 

[yugaaa]

I wanted to try out the amp .. so i had to use anything that was avaliable and it was my phone .

Yes , i did increase the gain by increasing the resistor value , but it i feel the sound is not as good as it is when using the 15k resistor . Still testing though since i made 4 modules for bridging into stereo . Will update as soon as it is done .

 

[yugaaa]

Here is my amp .. 4 modules done and working .. Now , in a fix as to how to bridge the amp . Do i use an external bridge circuit ?

 

[udailey]

check AN-1192. http://www.ti.com/lit/an/snaa021a/snaa021a.pdf

 

[masood]

dear apex,
i want to take this chip from national semiconductor as sample?how can i get it?
thanks

 

[masood]

Here is my amp .. 4 modules done and working .. Now , in a fix as to how to bridge the amp . Do i use an external bridge circuit ?

dear yugapa
do you obtain hi power by this amplifier.thanks masood

 

[kuldeepsingh]

dear apex,
i want to take this chip from national semiconductor as sample?how can i get it?
thanks

If you have any collage email id or company email id. just order samples from NS (now merged with TI). only u'll have to pay for shipping (some 250 Rs for 5 ICs). Bur mind it , its is only for DIY, no commercial use.

 

[syklab]

Actually they never charge for shipping.

 

[gadut]

I got question for this case, I try to calculate Ci based on LM3886 datasheet formula with below parameters:
- TDP 50watt, impedance 8ohm, input 1V, Rf22k; so you'll get Ri 1k3 and Ci 21uF
This case seems to be applied in many designs, but what if I increase Rf into higher value? below case for example
- TDP 50watt, impedance 8ohm, input 1V, Rf330k; so you'll get Ri 18k and Ci 1.5uF

Is it applicable to use high resistance on R feedback? I'm thinking to use high quality poly caps for this Ci, 1-2uF is still affordable, but not for 22uF

 

[kuldeepsingh]

Actually they never charge for shipping.

Its the import duty or custom clearance charges which we have to pay. Say i had paid 5$ in India.