A PCB-design for Phono-pre-amp

Roushon · 06:41 AM

Here is a single-sided pcb-design (with two jumpers) for a phono pre-amp circuit based on the National Application Note AN-1651.
I request for suggestions and corrections in the design.

Regards
Roushon

Joachim Gerhard · 14th May 2010, 12:01 PM

R18 and R19 have been swapped.

Joachim Gerhard · 14th May 2010, 12:02 PM

The output buffer may not be neccessary.

Roushon · 12:28 PM

Thanks Joachim. R18 is 38.7R. I corrected it now. I am following the Topology 2 (Active/Passive) in the application note. Half of IC4 is not used, so
I made a unity gain buffer out of it. I know it is not required, but it is not of any harm if added I hope.

Regards
Roushon

Joachim Gerhard · 14th May 2010, 12:39 PM

Putting a buffer in my sound better when you drive long and demanding cables, so yes, it does not hurt. You could also build a switchable subsonic filter.

Roushon · 14th May 2010, 01:01 PM

Quote:

Originally Posted by Joachim Gerhard

Putting a buffer in my sound better when you drive long and demanding cables, so yes, it does not hurt. You could also build a switchable subsonic filter.

That is a very good idea. Thank you very much. I will work on to convert the
unused opamp into a subsonic filter.

Best regards
Roushon.

mickeymoose · 14th May 2010, 01:06 PM

On the pcb: do not use 90 deg. anles on traces. In the etching process (especially home-made boards) undercutting at the anle could happen). Use only obtuse angles (135 deg. or greater). The star grounding you are employing is not required here. It is used in high power systems where a ground lead could be modulated causing hum and feedback. Not using star grounding can reduce the pcb size. E

Roushon · 15th May 2010, 06:39 AM

Quote:

Originally Posted by mickeymoose

On the pcb: do not use 90 deg. anles on traces. In the etching process (especially home-made boards) undercutting at the anle could happen). Use only obtuse angles (135 deg. or greater). The star grounding you are employing is not required here. It is used in high power systems where a ground lead could be modulated causing hum and feedback. Not using star grounding can reduce the pcb size. E

Thanks a lot for your suggestions. I will make the angles smooth. About the
ground connection can I make only one ground connection from the board, meaning, is fusing all the ground end from both upper and lower parts of the
pcb to a single point OK?

Regards
Roushon

binspaul · 15th May 2010, 09:05 AM

Hi,

I am also working on the same app note. But, I am using hard wiring with ultra pure silver wires instead of the PCB's. Also, I am using single opamp's instead of the dual version. What is the supply you are using ?

Best regards,
Bins.

Quote:

Originally Posted by Roushon

Thanks a lot for your suggestions. I will make the angles smooth. About the
ground connection can I make only one ground connection from the board, meaning, is fusing all the ground end from both upper and lower parts of the
pcb to a single point OK?

Regards
Roushon

Roushon · 15th May 2010, 12:24 PM

I will be using +-15v as shown in the application note made using LM317 and LM337. I have surface mount type ICs, so I need a PCB.

14th May 2010, 12:21 PM	#4
Roushon diyAudio Member Join Date: Sep 2004 Location: Mumbai (Bombay)	Thanks Joachim. R18 is 38.7R. I corrected it now. I am following the Topology 2 (Active/Passive) in the application note. Half of IC4 is not used, so I made a unity gain buffer out of it. I know it is not required, but it is not of any harm if added I hope. Regards Roushon __________________ S. Roushon Last edited by Roushon; 14th May 2010 at 12:28 PM.

15th May 2010, 12:24 PM	#10
Roushon diyAudio Member Join Date: Sep 2004 Location: Mumbai (Bombay)	I will be using +-15v as shown in the application note made using LM317 and LM337. I have surface mount type ICs, so I need a PCB. __________________ S. Roushon

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14th May 2010, 12:01 PM	#2
Joachim Gerhard diyAudio Member Join Date: Mar 2009	R18 and R19 have been swapped.

14th May 2010, 12:02 PM	#3
Joachim Gerhard diyAudio Member Join Date: Mar 2009	The output buffer may not be neccessary.

14th May 2010, 12:39 PM	#5
Joachim Gerhard diyAudio Member Join Date: Mar 2009	Putting a buffer in my sound better when you drive long and demanding cables, so yes, it does not hurt. You could also build a switchable subsonic filter.

14th May 2010, 01:06 PM	#7
mickeymoose diyAudio Member Join Date: Nov 2008	On the pcb: do not use 90 deg. anles on traces. In the etching process (especially home-made boards) undercutting at the anle could happen). Use only obtuse angles (135 deg. or greater). The star grounding you are employing is not required here. It is used in high power systems where a ground lead could be modulated causing hum and feedback. Not using star grounding can reduce the pcb size. E