lm4562 is cool!

[digi01]

i completed lm4562 preamp this weekend.i love it.

the attached is a photo of the real unit.i will post my pcb layout and sch file in a couple of days.
zang

[Tolu]

Hi Zang,

I love it, too.

I replaced the opamps (OPA2134) in my KR Audio Preamp with LM4562. It was an very audible improvement.

The "secret" for the use of LM4562 in a preamp is the following structure: input - 1st gain stage - pot - 2nd gain stage - output

The single use like pot + gain stage or buffer isn't satisfying (to my ears).

[digi01]

Hi Thomas,
Thank you for your ideaI will try it later.

the attached is my sch file.it is a DC amp.I keep it simple.

greetings from beijing,
Zang

[digi01]

The attached is my layout.
Consideration below:
1,the layout as compact as possible.
2,easy installation into a source or power amp.
3,smt & PDIP footprint.
4,simple power supply bypass.
5,big ground plate around opamp foot.

[tobebu02]

Hi Digi01,
Can you list the resistors & cap's values.
Thank you,

[digi01]

OK,

R1,3----------------1.2K
R2,4----------------100K
R5,6----------------39K
R7,8----------------415K
R9,10---------------12R
U1,2-----------------LM4562
C1,2,3,4,-----------35uf/25V

THE UNIT SHOULD RUN IN A BIT OF DAYS.
ZANG

[tobebu02]

Thank you very much.
Regards.

[AndrewT]

Hi Digi,
why run the signal through two stages of opamp?

Doing it the way you have will make conversion to Tolu's suggestion fairly easy.

Did you try a film or ceramic cap direct across V+ to V-? maybe 1uF

[digi01]

because i want the preamp driving lowZ headphones.this capability is very useful at live playing.
example:when i play my yamaha keyboard,i want monitoring the playback via a headphone.and the line out can work together.
as the datasheet shown,the lm4562 chip can drive complex loads,but it is no good for lowZ loading.so i do a circuit bending.

i have try a film cap direct across V+ to V- on some solid amp that is good.i will try it on this preamp later,thank you!
zang