Ventilation in amp case, regarding biasing and RF noise.

JoeM · 22nd January 2010, 11:30 PM

This is regarding the typical SS amps we are building here. I have noticed that taking the lid off affects the bias significantly and that has made me consider just how much ventilation is a good thing. If it aint getting hot in there (35C) , perhaps none is best...
Also what's required to shield RF? I imagine lot's of large holes will open it up to RF. Is mesh/screen better than holes or is that a myth?
How do you guys tackle the ventilation issue?

Wavebourn · 22nd January 2010, 11:36 PM

Here is my approach:

http://wavebourn.com/forum/download.php?id=123&f=7

JoeM · 23rd January 2010, 12:24 AM

A Nice looking amp

So I guess your electronics are quite exposed to draght and RF shielded by glass and mesh only. Well it's been done like that for ever with tubes. This aproach just wont help a (my) sensitive bias, that I know.
Does glass filter RF?

Wavebourn · 23rd January 2010, 12:56 AM

Hint: look at a microwave oven's door. It is covered by a perforated metal sheet. The oven contains dangerous microwave RF energy that does not leak out of the oven...
Got it?

Speedskater · 23rd January 2010, 01:18 AM

Are you sure that it's not light shinning on a light sensitive diode?

22nd January 2010, 11:30 PM	#1
JoeM diyAudio Member Join Date: Jan 2001	Ventilation in amp case, regarding biasing and RF noise. This is regarding the typical SS amps we are building here. I have noticed that taking the lid off affects the bias significantly and that has made me consider just how much ventilation is a good thing. If it aint getting hot in there (35C) , perhaps none is best... Also what's required to shield RF? I imagine lot's of large holes will open it up to RF. Is mesh/screen better than holes or is that a myth? How do you guys tackle the ventilation issue?

22nd January 2010, 11:36 PM	#2
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Here is my approach: http://wavebourn.com/forum/download.php?id=123&f=7 __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

23rd January 2010, 12:56 AM	#4
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Hint: look at a microwave oven's door. It is covered by a perforated metal sheet. The oven contains dangerous microwave RF energy that does not leak out of the oven... Got it? __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

23rd January 2010, 01:18 AM	#5
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	Are you sure that it's not light shinning on a light sensitive diode? __________________ Kevin

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23rd January 2010, 12:24 AM	#3
JoeM diyAudio Member Join Date: Jan 2001	A Nice looking amp So I guess your electronics are quite exposed to draght and RF shielded by glass and mesh only. Well it's been done like that for ever with tubes. This aproach just wont help a (my) sensitive bias, that I know. Does glass filter RF?

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