[charlo89]

I do not have the amp with me, I collect information and I will check everything this weekend.
The PSU Vellman support very well my transformer, it does not heat up (the s11 was very hot) and makes me a beautiful 30.0V.
 
Thank you for your infomations, I check this weekend.

 

[tangent]

Which Velleman supply is this?  They offer several.
 
If it's the K1823, I don't think it's safe to push its output to 30 V.  I know the docs say you can do that, but they're fudging things a bit.  With the parts they include, I wouldn't go higher than about 26 V.  You can change out some of the parts to get the 35 V they claim, but even then you'd want to make some changes to the design.
 
I cover this in some detail on my TREAD history page.