DC filament supply AC ripple affect on overall hum

[316a]

Bats

...hmmmm . I wonder if a similar scheme would work with a tungar rectifier charging the batteries ? Is this stupid enough ?

316a

 

[fdegrove]

EH,EH....

Hi,

Apart from the floating charging circuit your proposal is ideal (well, apart from bias stability).

While not adressed at my idea...it confirms my thinking...

Ta,

 

[EC8010]

Batteries and PSRR

Batteries are great not because they are quiet (although they are), but because they allow you to disconnect your heater supply from the noisy mains supply. Adding a charger instantly destroys that advantage. Of course, batteries change their terminal voltage as they discharge, so a driven valve has varying gm, which could be a problem.

 

[fdegrove]

RE:Batteries and PSRR

Hi,

First of all I can't be bothered with SLA supplies for heaters...they may sound better or not...
They're just too much hassle and I doubt they have that big an impact to justify their use.

Of course, batteries change their terminal voltage as they discharge, so a driven valve has varying gm, which could be a problem.

That can be solved by using higher B+ than needed and keep it constant, again, whether it's worth it is the question at hand...

I doubt it...
It is my conviction that good PSU design can really isolate the circuit from the mains to such an extend that battery supplies only become a rather expensive option that I just can't justify.

Cheers,