Roll Call: Who's building, built, or thinking of building a beta22?
Jul 17, 2013 at 8:09 AM Post #2,971 of 3,218
The idea behind the 6 board build is versatility.
 
properly done it can be used as 2 separate 3 board systems for 2 different inputs & outputs in the same build.
 
Jul 21, 2013 at 3:40 PM Post #2,972 of 3,218
Quote:
The idea behind the 6 board build is versatility.
 
properly done it can be used as 2 separate 3 board systems for 2 different inputs & outputs in the same build.

of course, to listen two headphones at the same time or with a friend eating a pizza
biggrin.gif

 
Jul 21, 2013 at 8:28 PM Post #2,973 of 3,218
Just a fair word of warning:
It feels great when you're just doing the physical process of building the amp, but once you hit the electrical troubleshooting... I haven't felt this much anxiety in a while. I had to dig into my old medication to handle how awful I felt today :frowning2:
 
Jul 21, 2013 at 9:36 PM Post #2,974 of 3,218
When I built mine I read the directions at least 10 times before I did the testing and biasing.  I was pretty scared to do that too.  When I tested my second board I smoked a part because the cheap clip-on leads I bought shorted the resistor I was measuring the voltage accross to the ground plane.  It turned out not to be so bad, Amb helped me figure out which parts to replace and how to test them.  Don't worry, you can do it!
 
Jul 23, 2013 at 8:27 AM Post #2,975 of 3,218
Quote:
I was under the idea aluminum is a very popular material for shielding though? The aluminum box should be preventing EMI leak from the transformer is what I was led to believe.

 
Aluminium is a good shielding material for radio waves, but does diddly squat for magnetic fields from the transformer. Get rid of it and wire as if for a one-box build.
 
Jul 23, 2013 at 10:19 AM Post #2,976 of 3,218
Quote:
 
Aluminium ... does diddly squat for magnetic fields from the transformer.

 
Absolutely correct.
 
Don't forget to try out the transformer in different orientations to see which is quietest. This is important, it can make a big difference. Just listen to the amplifier turned up full with a source plugged in but with nothing playing and turn the transformer around every which way to see if you can hear any difference.
 
w
 
Jul 23, 2013 at 10:29 AM Post #2,977 of 3,218
I found IEMs very handy in determining if you are hearing any transformer noises.  But I built a 2x gain B22, so YMMV.  If you are building 6x or 8x or whatever the default is then you may be able to hear any noises just fine with your regular headphones.  Also, having the source plugged in and not playing is a must, or you will just hear an unterminated connection.
 
Jul 23, 2013 at 10:43 AM Post #2,978 of 3,218
Quote:
 
Aluminium is a good shielding material for radio waves, but does diddly squat for magnetic fields from the transformer. Get rid of it and wire as if for a one-box build.

...or one transformer with plastic box like nuvotem-talema and a iron box coated with copper foil

 
Jul 23, 2013 at 11:09 AM Post #2,979 of 3,218
Quote:
 
Absolutely correct.
 
Don't forget to try out the transformer in different orientations to see which is quietest. This is important, it can make a big difference. Just listen to the amplifier turned up full with a source plugged in but with nothing playing and turn the transformer around every which way to see if you can hear any difference.
 
w

 
good advice and something i do will all my builds before drilling out the TX mounting hole.
 
Jul 23, 2013 at 2:06 PM Post #2,980 of 3,218
Quote:
...or one transformer with plastic box like nuvotem-talema and a iron box coated with copper foil

 
If you want shielding, don't do a half-assed homebrew job - do it properly and get a factory-shielded unit. l have several SumR ones that are all perfect, and very affordable.
 
Jul 23, 2013 at 2:14 PM Post #2,981 of 3,218
x2 on the SumR recommendation.  they're completely shielded/encapsulated and very reasonable and excellent quality.  i consider the added cost cheap insurance for a noise free, single chassis build. 
 

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