Need help with lm4700 schematics

[abraxa]

Hi

I'm in the process of making an amp with lm4700. This is my first amp, som im not really sure what design to use. There are plenty of circuit diagrams for lm3875 out there, but i haven't managed to find a single one for lm4700, except for the ones in the data sheet (.link).

So far ive collected most of the parts; a transformer with dual secondaries (15V/80VA), 4 x 80V 10000 uF caps, a 50k stereo alps potmeter for the volume control, a few rectifier bridges and of course 2 x lm4700. I also have lots of other caps and resistors.

If someone could help me out with the circuit diagram for this amp it would really be appreciated! Especially with the input, and how the potmeter could be integrated into the circuit

[Netlist]

Indeed, apart from the datasheet there's not a lot around.
So finally, you'll be the first to release something out of the obvious.
Maybe this might reveal something?

/Hugo

[demogorgon]

Hoisann!
velkommen til diyaudio. flott side i grunnen!
alltid hyggelig med flere normenn her og

National really has what you need.

maby add a litle snubber to those 10.000uf caps and a buffer, change the feedback resistors to 220k and 20k respectivly.

is i have promised you before, i will make a simple circut diagram of how i have done things, and how i would do things the second time around with the lm4700.

edit: funne that almost all hits on the lm4700 are threads i have created or participated?
you guys should try it. it leaves the lm3886 in the dust when it comes to mids and treble. a litle less bass deffinition, but i find the bass maby a bit murcy on the lm3886.

[abraxa]

Thanks for the reply, I know you said you were making a circuit Demogorgon, but its been quite a few weeks and I didn't want to bother you too much

Well, I pulled myself together and modified a design i found in the Eagle archives. Be gentle, im still learning I know the pin numbers on the ic don't match, but i couldnt figure out how to change them. Theyre supposed to be numbered as the first circuit in the data sheet.

I have no idea what a snubber is, but I'm guessing CS1/C2 and CS2/C3? No guesses on buffer tho. RB and R-IN should probably have other values since I changed the input potmeter from 10K to 50K, but I'm not sure how to calculate them.

Any comments?

[karahara]

Looks good. Currently I'm also working on a LM4700 amp, so far I've also created a Schematic.

Your Cin and Rin seem to be a good idea.
In my Schema I've left out the marked * Optional components.

greetz
karahara

edit:
Feedback resistance will be mounted offboard!

[demogorgon]

abraxa: yes, i know i said to do it a long time ago, but you know how school can be. then throw in the 4day a week working out, and the band practises 3 days a week, and you dont have a lot of spare time on your hands..

I'm going to portugal in three wekks time though, will be printing pdf's like hell and hopefully borrow a laptop at school, calling it schoolwork. installing orcad, and get some work done while laying on some towel on a sandy beach, getting a tan

or i can just do a quick one now, in paint..

[karahara]

New one, with Input Cap+Resistor

[karahara]

Me again, now with some pcb-artwork
Comments welcome

[demogorgon]

I ****ed up when trying to remove a NC pin on the repalcement IC..

it wasn't the NC pin i removed..
it was the ouptut pin..

so i moved over to the lm3886..
i had a few of them as well, so i thought i'd might try to copy teh work of carlosfm.

i found the orcad software to have to many limitations to actually use, it was a demo version.

karahara, i found the picture a litle unrevealing, where are your ground traces?

[karahara]

Damn NC-pins

Here's the pic without the Groundplane, Gnd is where K7, K4, K2 are.