LM3886 Schematics + PCB

[apexaudio]

Sir mile please response... my transformer is 22-0-22vAC (+/-30vDC).
what would be the zener diode voltage rating instead of 16v?
I am saying about apex lm3886 gainclone ver:1

Use 10-12v zener

 

[NanoFarad]

Use 10-12v zener

Thnk you so much Sir

 

[NandhakumarV]

Hi,


I like to Parallel Super Gainclone, like as mentioned in Parallel LM3886 Diagram using wire wound 0.5 ohm 1 watt resistor (3) per channel and ground with 0.1uf (ceramic or film capacitor) with 2 ohm 1/w metal resistor.


Mile, Prasi can you guys just confirm whether it will work or not.


Thanks in Advance,
Nandhakumar

 

[NandhakumarV]

Plz reply

 

[NandhakumarV]

Hi,

I am about to build super gain clone. Waiting for PCB to arrive. Mean time i like to know the power requirements, -+35v what abt amps. How much amp required for single board and what about 5 such boards

Mile, Prasi and others plz help


Thanks,
Nandhakumar

 

[CptnAwesome]

Following the datasheet, a single lm3886 can handle 50W cont. avg. output power into a 8Ohm load with supply voltage +-35V --> I = sqrt(P/R) = sqrt(50/8) = 2,5A
So it needs 2,5A continuous current
and 2,5*sqrt(2) = 3,54A peak current


Multiply those values times 5 and you get what 5 of such boards need

 

[Kay Pirinha]

Following the datasheet, a single lm3886 can handle 50W cont. avg. output power into a 8Ohm load with supply voltage +-35V --> I = sqrt(P/R) = sqrt(50/8) = 2,5A
So it needs 2,5A continuous current
and 2,5*sqrt(2) = 3,54A peak current

C'mon! 2 * 35V * 2.5 A = 175 W. At full output power of 50 watts that would equal to 125 watts of thermal dissipation. Never ever!


Best regards!

 

[NandhakumarV]

Any good power supply design for ac to dc to get 35v

 

[CptnAwesome]

C'mon! 2 * 35V * 2.5 A = 175 W. At full output power of 50 watts that would equal to 125 watts of thermal dissipation. Never ever!


Best regards!

You're right. That sounds a little bit too much.
But whats wrong about my calculation then?

 

[CptnAwesome]

Actually are you shure that heat dissipation of an amp is calculated like that?

 

[Kay Pirinha]

Yes, dissipation always is input DC power minus output power.

Btw, 1.25 A of DC consumption, which is half of the value that you've calculated, seem to be more reasonable: 35 V * 2 * 1.25 = 87.5 W, minus 50 W output = 37.5 W dissipation. Remember that each half wave only draws current from one rail, not from both simultaneously.

Best regards!

 

[CptnAwesome]

Ah yeah that solution is definitely right.
But i think its just 35V * 2,5A = 87,5W

 

[NanoFarad]

Use 10-12v zener

Sir mile i have another question. Actually i am kind of dumb
I didn't mention trafo VA rating. 22-0-22vAC 5amps (220VA).
Do you think 10-12v zener will work properly when fully loaded?
Thnks & no more questions
Have a good day.

 

[prasi]

NandhakumarV

See if this is useful to you.

 

[NandhakumarV]

Thanks to All

Hi Guys,

Thanks for the help Prasi.

I am looking for power supply design. If possible any one has some good design to feed 35v dual supply with components list then share it to me. It will be a great help for me.


Thanks and Regards,
Namdhakumar
,

 

[jemraid]

Hello Namdhakumar

Please take a look at this page, it's Mick Feuerbacher's 2 resistor 3886
Mick Feuerbacher Audio Projects
The power supply is a bit furher down the page
I'm making it at the moment and got one channel rigged up and laughed out loud when I heard it, fast, analytical, transparent, huge dynamic range

But then I'm just a listener

Cheers

 

[bender460]

I did something similar to this.

 

[jemraid]

Hello Bender,

So did I with an LM3876.
In my opinion the LM3886 without the PS capacitors sounds a lot better.
This goes right back to Mr Kimura, I would respectfully suggest that he is right.

Cheers

 

[bender460]

I think one can be pretty flex able on the power supply and get good sound.

 

[jemraid]

Hello Bender,

Your quite right flexible is the key.
The simplest option is mostly the best one.
As I have found out for myself

Cheers