The Beta 22 Thread

[jinp6301]

i think he went for the Ck2III balanced instead

 

[cotdt]

The hum is probably not from the transformer but from the volume pot or your AC/DC lines too close together near the S22. it could also be a grounding issue. or you can just go balanced and not worry about all that stuff. i've noticed the hum completely disappear in certain other amps when balanced. never heard any hum from the Beta22 though.

 

[amb]

ast,

What material is your transformer box made of? Does it have additional magnetic shielding material in it?

n_maher's β22 has a steel box around the transformer, but that alone is not enough to cure the hum. The box is lined with a lot of stuff from lessemf.com, as are some of the signal wiring. I'll let him provide more details.

 

[OverlordXenu]

Oh how I want a Beta22...You are all terrible.

 

[luvdunhill]

Quote:

Originally Posted by amb /img/forum/go_quote.gif ast, What material is your transformer box made of? Does it have additional magnetic shielding material in it? n_maher's β22 has a steel box around the transformer, but that alone is not enough to cure the hum. The box is lined with a lot of stuff from lessemf.com, as are some of the signal wiring. I'll let him provide more details.

amb:

is there any reason to believe that a two box configuration would not fix this issue?

 

[amb]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif is there any reason to believe that a two box configuration would not fix this issue?

It certainly would fix the issue completely. But some people prefer a single-box solution.

 

[ast]

Quote:

Originally Posted by amb /img/forum/go_quote.gif ast, What material is your transformer box made of? Does it have additional magnetic shielding material in it? n_maher's β22 has a steel box around the transformer, but that alone is not enough to cure the hum. The box is lined with a lot of stuff from lessemf.com, as are some of the signal wiring. I'll let him provide more details.

Hi Ti,

it is a diecast Al alloy case from Hammond: http://www.hammondmfg.com/dwgfl.htm


Do you think it is not sufficient to shield EMI ?




...

 

[ast]

Quote:

Originally Posted by cotdt /img/forum/go_quote.gif The hum is probably not from the transformer but from the volume pot or your AC/DC lines too close together near the S22. it could also be a grounding issue. or you can just go balanced and not worry about all that stuff. i've noticed the hum completely disappear in certain other amps when balanced. never heard any hum from the Beta22 though.

Balanced config is not an option for at this stage since all my phones are singled-ended.


I will move the transformer outside of the box and see if that will help. Or switch the location of S22 and the transformer.


...

 

[amb]

Quote:

Originally Posted by ast /img/forum/go_quote.gif it is a diecast Al alloy case from Hammond: http://www.hammondmfg.com/dwgfl.htm Do you think it is not sufficient to shield EMI ?

No. You need something that has high magnetic permeability, which aluminum isn't. No wonder you're still getting hum.

Moving the transformer away from the amp is the most effective solution.

 

[ast]

Quote:

Originally Posted by amb /img/forum/go_quote.gif No. You need something that has high magnetic permeability, which aluminum isn't. No wonder you're still getting hum. Moving the transformer away from the amp is the most effective solution.

moving the trany outside will be a cosmetic mess

I'd prefer to get an effective shield and keep everything inside. Any recommendations?






....

 

[amb]

Quote:

Originally Posted by ast /img/forum/go_quote.gif I'd prefer to get an effective shield and keep everything inside. Any recommendations?

Then I recommend that you follow n_maher's footsteps and use a steel box for the transformer, and liberally line the inside with magnetic shielding material. He also used some magnetic shielding on the signal wiring.

 

[ast]

Quote:

Originally Posted by Nebby /img/forum/go_quote.gif I already have some magnetic shielding material on order, I liked the box because it made it look pretty ......

May I ask what and where I can order them?







Thanks!

 

[fierce_freak]

http://www.lessemf.com/274.html

 

[ast]

Quote:

Originally Posted by fierce_freak /img/forum/go_quote.gif http://www.lessemf.com/274.html

Thanks!







...

 

[ast]

...




[size=large]Aha! problem solved! Now there is absolutely ZERO huming noise:[/size]

....