Humming from WCF but not SRPP

Brit01 · 22nd August 2010, 03:09 AM

Used exactly the same power supply for a WCF headphone amp and just got humming from the PSU.

With the SRPP set up, same chassis/grounding etc, dead quiet.
Is the WCF more susceptable to noise?

I do like the SRPP a lot.
Just trying out it with some 5687 now. Loved the 6N6P.

Poindexter · 22nd August 2010, 03:17 AM

SRPP has very good PSRR. How much ripple on your B+?

P

Brit01 · 22nd August 2010, 03:35 AM

not sure in this moment. My PSUII just crashed!!

For the SRPP:

Hexfreds
1uf
1K
200uf
1k
200uf/bypassed with 0.1 MKP10 Wima

Same caps with WCF, just varied resistors for correct B+.

Poindexter · 22nd August 2010, 05:03 AM

not sure in this moment. My PSUII just crashed!!

'king measure it!

Put a biggazz choke in place of the first resistor. 10H minimum. I use 25H.

P

Brit01 · 22nd August 2010, 01:48 PM

Wish it was that easy to buy a choke. Can't even buy caps bigger than 250V, they have no idea what PIO is, and OPT's forget it.

Well I think I'll just stick with the old trusted SRPP.

(I live in Uruguay!)

Brit01 · 22nd August 2010, 08:37 PM

I'm running a SRPP and trying out with different CCS on top and bottom cathodes.

Set up a DN2540 on the cathode of the top tube which works nicely.

But I thought I understood how to use a LM317 on the cathode of the bottom tube. Obviously not.
I had a Voltage of 1.21 V on the output of the LM317 with a resistor of 68 ohms.
So about 18 mA no?

So why does it not work? Just get a total distorted mess.

What am I doing wrong?

LED bias: If I have a voltage of 2.2V on the cathode with an LED with 130V on the anode of the bottom tube, how can I work out the current? I realise it sets up a constant voltage source but still confused.

I'm using 6N6P's in a headphone configuration.

Thanks

22nd August 2010, 03:09 AM	#1
Brit01 diyAudio Member Join Date: Jul 2008	Humming from WCF but not SRPP Used exactly the same power supply for a WCF headphone amp and just got humming from the PSU. With the SRPP set up, same chassis/grounding etc, dead quiet. Is the WCF more susceptable to noise? I do like the SRPP a lot. Just trying out it with some 5687 now. Loved the 6N6P.

22nd August 2010, 08:37 PM	#6
Brit01 diyAudio Member Join Date: Jul 2008	Confused with LM317 and LED bias I'm running a SRPP and trying out with different CCS on top and bottom cathodes. Set up a DN2540 on the cathode of the top tube which works nicely. But I thought I understood how to use a LM317 on the cathode of the bottom tube. Obviously not. I had a Voltage of 1.21 V on the output of the LM317 with a resistor of 68 ohms. So about 18 mA no? So why does it not work? Just get a total distorted mess. What am I doing wrong? LED bias: If I have a voltage of 2.2V on the cathode with an LED with 130V on the anode of the bottom tube, how can I work out the current? I realise it sets up a constant voltage source but still confused. I'm using 6N6P's in a headphone configuration. Thanks

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22nd August 2010, 03:17 AM	#2
Poindexter diyAudio Member Join Date: Oct 2004 Location: Maui, Hawai'i, USA	SRPP has very good PSRR. How much ripple on your B+? P

22nd August 2010, 03:35 AM	#3
Brit01 diyAudio Member Join Date: Jul 2008	not sure in this moment. My PSUII just crashed!! For the SRPP: Hexfreds 1uf 1K 200uf 1k 200uf/bypassed with 0.1 MKP10 Wima Same caps with WCF, just varied resistors for correct B+.

22nd August 2010, 05:03 AM	#4
Poindexter diyAudio Member Join Date: Oct 2004 Location: Maui, Hawai'i, USA	not sure in this moment. My PSUII just crashed!! 'king measure it! Put a biggazz choke in place of the first resistor. 10H minimum. I use 25H. P

22nd August 2010, 01:48 PM	#5
Brit01 diyAudio Member Join Date: Jul 2008	Wish it was that easy to buy a choke. Can't even buy caps bigger than 250V, they have no idea what PIO is, and OPT's forget it. Well I think I'll just stick with the old trusted SRPP. (I live in Uruguay!)

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