oneplustwo F5 build thread - Page 22

6L6 · 8th April 2012, 05:32 PM

Well the good news is that it's hum, not ripple. Now you need to fix the hum...

oneplustwo · 9th April 2012, 02:21 AM

Quote:

Originally Posted by 6L6

Well the good news is that it's hum, not ripple. Now you need to fix the hum...

Ok. I'll try playing with the grounding scheme. Also, I want to try my DAC and see if that makes a difference in terms of audible hum.

Any other recommendations?

Andersonix · 9th April 2012, 03:02 AM

Put it in a steel box.

oneplustwo · 9th April 2012, 05:39 AM

Quote:

Originally Posted by Andersonix

Put it in a steel box.

The speakers? Yah, I guess that would get rid of the hum.

DAC didn't reduce the hum. Will try options with the earth ground wire next.

6L6 · 9th April 2012, 03:26 PM

The Earth ground probably isn't it, but do try a couple of configurations, you will probably make it quieter.

Look at the signal grounding, start by removing one of the ground wires from the PSU board and attaching both ground wires to the same point on the psu (I.E., both signal grounds to one side.)

There was a guy who recently had a similar problem with the red board psu, I will try to dig it up.

oneplustwo · 9th April 2012, 06:33 PM

Aha! I think I forgot to tie the signal ground to the PSU board in the first place!

Oops. I will try that tonight and see what happens.

Zen Mod · 9th April 2012, 06:44 PM

NTC please

oneplustwo · 07:03 PM

Sorry, what does NTC mean?

EDIT: NTC is the CL-60 thermistor? In which case, I think I'm good since the PSU PCB is already populated with that.

6L6 · 9th April 2012, 07:07 PM

Yes, the NTC is the CL-60 ground-breaker. Not the 2 in the PSU being used as the inrush suppressors.

Attach the signal grounds to the ground-breaker, and at the same spot. Hopefully that's the problem.

Bksabath · 9th April 2012, 07:07 PM

Negative Themperature Coefficent

Also on bias thermistors 4.7K

8th April 2012, 05:32 PM	#211
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	Well the good news is that it's hum, not ripple. Now you need to fix the hum... __________________ llustrated Build Guides - Pass Pearl 1 - Pass B1 - - Pass F5 - Pearl 2 - -O2 HPA - - Pass F4

9th April 2012, 03:26 PM	#215
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	The Earth ground probably isn't it, but do try a couple of configurations, you will probably make it quieter. Look at the signal grounding, start by removing one of the ground wires from the PSU board and attaching both ground wires to the same point on the psu (I.E., both signal grounds to one side.) There was a guy who recently had a similar problem with the red board psu, I will try to dig it up. __________________ llustrated Build Guides - Pass Pearl 1 - Pass B1 - - Pass F5 - Pearl 2 - -O2 HPA - - Pass F4

9th April 2012, 06:44 PM	#217
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	NTC please __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

9th April 2012, 07:00 PM	#218
oneplustwo 1.21 Gigawatts?! diyAudio Member Join Date: Apr 2009 Location: San Francisco	Sorry, what does NTC mean? EDIT: NTC is the CL-60 thermistor? In which case, I think I'm good since the PSU PCB is already populated with that. Last edited by oneplustwo; 9th April 2012 at 07:03 PM.

9th April 2012, 07:07 PM	#219
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	Yes, the NTC is the CL-60 ground-breaker. Not the 2 in the PSU being used as the inrush suppressors. Attach the signal grounds to the ground-breaker, and at the same spot. Hopefully that's the problem. __________________ llustrated Build Guides - Pass Pearl 1 - Pass B1 - - Pass F5 - Pearl 2 - -O2 HPA - - Pass F4


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9th April 2012, 03:02 AM	#213
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	Put it in a steel box.

9th April 2012, 06:33 PM	#216
oneplustwo 1.21 Gigawatts?! diyAudio Member Join Date: Apr 2009 Location: San Francisco	Aha! I think I forgot to tie the signal ground to the PSU board in the first place! Oops. I will try that tonight and see what happens.

9th April 2012, 07:07 PM	#220
Bksabath diyAudio Member Join Date: Dec 2007	Negative Themperature Coefficent Also on bias thermistors 4.7K

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