Anurag,

You statement about the humming is from all the hammond transformers users on the internet.  They are built understacked for profit and will hum no matter what.
The reason we seen this overbuilding of the power trans we knew what was going on.  When a transformer is built correctly it will NOT hum or hum very little if very large.  When you use the hammond logic to purchase a properly built transformer, you will get a higher voltage due to it being underloaded. This is the problem we see and present to you.
They have brainwashed most of the builders out there and we deal with this everyday.  A transformer properly built will not hum and when correctly loaded to the circuit needs, it will operate perfectly.

We saw the circuit and it appears OK, the LED in the cathode was well as the tube used is a VHF type, the LED is an oscillator in the nano wave spectrum and its subharmonics WILL appear on the signal when a good scope is used.
Check the internet for this.
It will appear as a little spike on the tip of the sinewave.

Also, when you use a 200ma choke fro 50ma, it will not filter. 50ma needs a
20H+ to filter at 120hz.
Your idea for building large for hum will work for mechanical hum but the amp will hum.
We suggest you spec the transformer for the voltage and current needed and the choke for the current used.
Outputs are OK.

Please research this information and get back to us.

Jack Elliano
Electra-Print Audio