Riaa Pacific Jfet

maxpou · 8th April 2006, 01:56 AM

I MAKE PCB FOR RIAA BUT I HAVE NOISE. SOMEBODY HAVE A PCB FOR THIS PHONO OR HOW I PLACED RCA GROUND AND PS GROUND. THANK'S

peranders · 8th April 2006, 06:35 AM

How does your power supply look like?

maxpou · 8th April 2006, 02:06 PM

I HAVE A HAMMOND TOROIDAL TRANSFORMER 44V CENTER TAP 160VA, 4 CAP 4700UF NICHICON FW DECOUPLING 0.01 POLYESTER METAL BY CHANNEL. PHILIPS AND 2 REGULATORS 7824 VISHAY ONE FOR EACH CHANNEL. THANK YOU!

Netlist · 8th April 2006, 02:11 PM

Maxpou,
Please turn off the Caps-lock. I'm sure it's not your intention but this style is considered as shouting.
As for the PSU, a schematic would be handy as well.

/Hugo

peranders · 8th April 2006, 04:13 PM

7824 regulator might be too noisy, just a hunch. How much decoupling do you have after the regulators?

maxpou · 9th April 2006, 04:43 PM

i have 4 caps 4700uf decoupling with 0.01 by caps by regulator. thank you!!

davidsrsb · 10th April 2006, 02:09 AM

This circuit has a low first stage gain followed by the RIAA network attenation so it won't be that quiet. As Peranders has said, it is also very sensitive to supply noise.

maxpou · 10th April 2006, 04:47 AM

which circuit you propose for power supply?

Onvinyl · 10th April 2006, 11:23 AM

Hi,
Try batteries with as much bypass capacitance you can afford.
Apart from PSU, this is a forgiving circuit: it was my first project a while ago since 15 years or so and it worked quiet good.
Rüdiger

jackinnj · 10th April 2006, 11:55 AM

you can use this "cleanup" circuit from Wenzel Associates -- the entire article can be found on their website. Just make sure that the opamp you use can take the voltage. (i.e. you don't want to use one of those low power, low voltage ones.)

Paralleling more 2sk170's on the front end will reduce "device" noise further (at the expense of more current consumption).

http://www.wenzel.com/documents/finesse.html

8th April 2006, 06:35 AM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	How does your power supply look like? __________________ /Per-Anders (my first name) or P-A as my friends call me

8th April 2006, 04:13 PM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	7824 regulator might be too noisy, just a hunch. How much decoupling do you have after the regulators? __________________ /Per-Anders (my first name) or P-A as my friends call me

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8th April 2006, 02:06 PM	#3
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	I HAVE A HAMMOND TOROIDAL TRANSFORMER 44V CENTER TAP 160VA, 4 CAP 4700UF NICHICON FW DECOUPLING 0.01 POLYESTER METAL BY CHANNEL. PHILIPS AND 2 REGULATORS 7824 VISHAY ONE FOR EACH CHANNEL. THANK YOU!

8th April 2006, 02:11 PM	#4
Netlist diyAudio Moderator Join Date: Jan 2003	Maxpou, Please turn off the Caps-lock. I'm sure it's not your intention but this style is considered as shouting. As for the PSU, a schematic would be handy as well. /Hugo

9th April 2006, 04:43 PM	#6
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	i have 4 caps 4700uf decoupling with 0.01 by caps by regulator. thank you!!

10th April 2006, 02:09 AM	#7
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	This circuit has a low first stage gain followed by the RIAA network attenation so it won't be that quiet. As Peranders has said, it is also very sensitive to supply noise.

10th April 2006, 04:47 AM	#8
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	which circuit you propose for power supply?

10th April 2006, 11:23 AM	#9
Onvinyl diyAudio Member Join Date: Aug 2002 Location: Germany	Hi, Try batteries with as much bypass capacitance you can afford. Apart from PSU, this is a forgiving circuit: it was my first project a while ago since 15 years or so and it worked quiet good. Rüdiger

10th April 2006, 11:55 AM	#10
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	you can use this "cleanup" circuit from Wenzel Associates -- the entire article can be found on their website. Just make sure that the opamp you use can take the voltage. (i.e. you don't want to use one of those low power, low voltage ones.) Paralleling more 2sk170's on the front end will reduce "device" noise further (at the expense of more current consumption). http://www.wenzel.com/documents/finesse.html

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