[regal]

If I have a DC tube heater power supply in a separate chassis should I add a decoupling cap on the heater supply in the amp chassis near the tubes?

 

[ericj]

You expecting some sort of high frequency switching in tungsten filaments or something?
 
(Short answer: No reason at all)
 
(More snarky answer: Twist and route your heater wires properly and there is no reason for DC heaters in the first place)
 

 

[adamus]

Regal, as you saw from my two chassis build, i used DC heaters and dual chassis. I used 1084 series adjustable regs, super simple and stable, everythin looks great on the scope with no local decoupling.
 
agree with Ericj to some extent, but by going DC the almost garantee you will get a noise free heater setup is very attractive, and an option i will take in the future if going down the custom Tx route.. You do need an 8 or 9v.

 

[bidoux]

What about a DC regulated filament supply ? I am building a tube amp (it is going to take some time), dual chasis, regulated power supplies. Using point to point wiring, it is not that complicated to add an extra capacitor directly soldered on the tube socket.

It should look like this : http://img37.imageshack.us/i/alimlentationfilaments.jpg/.  The transistors are two MJ11016. It is supposed to power two 6080 and one ECC88 (around 6 ampère)

 

[regal]

Quote:

You expecting some sort of high frequency switching in tungsten filaments or something?
 
(Short answer: No reason at all)
 
(More snarky answer: Twist and route your heater wires properly and there is no reason for DC heaters in the first place)
 

 
 
I'm just used to having some capacitance reservoir after a long run of wire.
Its so easy and cheap it implement DC that I just use it,  with Grados you hear everything.  If it were less sensitive phones AC Heat is nice and the spike at 60hz probably adds some warmth

 

[nikongod]

I'd say overkill, but small caps are cheap.
 
If you bias AC heaters above cathodes you dont hear them except with (extremely) microphonic tubes, very high gain stages, and poor signal VS heater wiring. 
 
If you want really quiet heaters: bias the heaters several volts above cathode AND use DC. It takes a bunch of caps, but its VERY quiet.
 
Tangentally:
Whats with everyone interchanging the terms "filament" and "heater" recently? Its not you bidoux, I'm seeing it all over the place. 
 
Heaters are separate from the cathode, as found on INDIRECLTY heated tubes like the kt90, 12sn7, 7dj8, 12a*7, etc
Filaments are the cathode as well as the heating element. as found on DIRECTLY heated tubes like the 6b4g, 46, 307A, etc.
 
grumbles.