LM833 RIAA Phono Preamplifier

[gmilitano]

Greetings,

I would like to try out a phono preamplifier using the LM833. I have searched diyAudio and it appears opinons are split on the performance of this op amp. Since I already have a few of these chips, I would like to try them out as a phono preamp.

So I have gone through the National Application Note AN-346:

http://www.national.com/an/AN/AN-346.pdf

and I have a few questions.

I have attached the schematic from the Application Note for reference.

1. For a power source, I would like to use two 9V batteries. The note shows a +/- 15V supply. Is a 9V supply too low? What effect will the lower voltage have?

2. I have also gone through the calculations and it appears that values for C4 and C0 do not need to be nearly as large as the values shown on the schematic! Based on my calculations, and selecting rolloff frequencies of a little below 20Hz, I calculate that 0.22uF for C4 and 22uF for C0 should be more than adequate. Have I made a mistake somewhere?

I would also be appreciated if you could share some links that use the LM833 as a phono preamp.

Regards,
Gio.

 

[sam9]

This is almost "the basic generic phono preamp". I've seen the basic circuit in many different books, articles, etc. Each one used a different opamp and each used different cap and resistor values (consistent with the formulas). I suspect they all work. I suspect the component choices were for reasons just like yours -- what ever they had on hand in their component box.

I'm not very much into LPs any more so my opinions on sound quality are far from authoritative. Nonetheless, I suspect that only the most devoted vinyl fans will notice any short commings to the version you propose to build and they would probably want a more elaborate (exotic?) circuit anyway.

 

[EUVL]

Tons of info here (Thread -- The best phono preamp on op-amps?) :

http://www.diyaudio.com/forums/showthread.php?s=&threadid=50530&highlight=

Patrick