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6SN7 Mu follower or cathode follower?

I tried elevating the heater rails in mu follower but didint work.
Here is the sch of the cathode follower im planning to use.
 

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What is the intended purpose of this amplifier stage ??? Is it for line-level pre-amp ??

Yes it is for linestage.

My major concern was hum in the prestage for which once I tried keeping everything out of metal chassis ( made of mild steel ) and then later when moved to mild steel im getting constant hum.

Now im using CLC setup like 220uF/450V , 2H ( iguess ), 220uF/450V but now im thinking to move to as LCC combination that first the peak voltage be suppressed by the choke and then to use caps after that.

I have been said that using Mu follower its very sensitive to the power supply ripple so thinking to move to Cathode follower. Any input that anyone can provide will be very helpful.
 
A mu follower should have good PSRR, so should not be too sensitive to ripple.

You keep talking about switching between mu follower and cathode follower, as though these two quite different circuits are comparable in some way. They are not. If one of these seems to satisfy your needs, then it is almost certain that the other one will not.

The mu follower is not a follower, so it is an unfortunate name but too late to change it now. It is essentially a mu gain stage closely coupled to a modified cathode follower.
 
Yes it is for linestage.

My major concern was hum in the prestage for which once I tried keeping everything out of metal chassis ( made of mild steel ) and then later when moved to mild steel im getting constant hum.

Now im using CLC setup like 220uF/450V , 2H ( iguess ), 220uF/450V but now im thinking to move to as LCC combination that first the peak voltage be suppressed by the choke and then to use caps after that.

I have been said that using Mu follower its very sensitive to the power supply ripple so thinking to move to Cathode follower. Any input that anyone can provide will be very helpful.

Can you upload à picture of your amplifier? While your mild steel enclosure is transporting the magnetic field originating from the power transformer and choke, there is no part amplifying this field. Or, possibly the anode when iT is near.
 
Folks, the OP is comparing a mu-follower to a two-stage common-cathode DC-coupled to cathode-follower. Gain would be in the ballpark/similar (mu-follower somewhat higher gain).

Theoretically, the mu follower should have better PSRR than the common-cathode+CF.

Why not wire it up point-to-point to troubleshoot the hum issue, then lay out the PCB after you've solved the problem?

Also, grid stopper resistors might be helpful.