DC Tube Heaters

[Bengali]

Hi,

just curious if anyone has compared the sound between simple DC heater psu vs. Volt. Reg. PSU.

1. F.W.B to R to C (10,000uF)
2. F.W.B to LM1084 V.Reg.

I'm wondering if the the volt. reg. heater psu limits the sound. This is for line stage.

 

[Vinylsavor]

Hi!

If this is for indirectly heated tubes, the differences will not be worth worrying about.

If this is for directly heated tubes, neither will sound good. Either use a current reg, or the dedicated fil regs offered by Rod Coleman, or use the purely passive LCL approach which I prefer

Thomas

 

[Wavebourn]

I disagree, Thomas.
In my recent 4P1L project I used floating 6.3V voltage stabilizer (for indirectly heated), and 3 Ohm resistors in series with each half of 4P1L filaments. No difference in sound VS floating batteries.

 

[Vinylsavor]

Hi!

I wrote that there will be no significant differences with indirectly heated tubes so I guess we agree 😉

Thomas

 

[Vinylsavor]

Hi again,

just saw in your other thread, that the tube you mentioned is actually directly heated.

Ok, if you don't hear a difference with that one, it doesn't mean that there will be no difference with other DHTs. I got significant differences between filament supplies with DHTs. Some respond more to the fil PSU, some less.

Generally my first axiom in audio is:

If you can't hear a difference, it does not mean that there really is no audible difference. Of course the opposite holds true es well: If you hear a difference, it doesn't mean that there really is a one.

😉

Best regards

Thomas

 

[Wavebourn]

If you can't hear a difference, it does not mean that there really is no audible difference. Of course the opposite holds true es well: If you hear a difference, it doesn't mean that there really is a one.

Agree! 😀

 

[Bengali]

Thanks Thomas.

yes, for indirect heater. 12au7, 6DJ8,etc...

I have never played with DHT's.

I do prefer using the LM1084 for fixed voltage, soft start and some short circuit protection for sanity.

If you can't hear the difference,............, you save a LOT of money!!!!! 😀

 

[nigelwright7557]

I had trouble with hum in my pre amp so I changed to DC heaters and the hum was still there. The hum was coming from other sources like transformer magnetic field and bad wiring.

 

[andyjevans]

I've tried several DC heaters options for DHTs. I'd rank them as follows:

Best:
Choke input supply followed by Rod Coleman board
Double choke input supply

Then:
Rod Coleman board

Then:
LM1084 as current sink
LM1084 as voltage reg followed by a CMC
(The above are improved by a further LM1084 before, as Ronan Reg)
Various other common voltage regs

I didn't find batteries were necessary or much better and wouldn't go to the trouble of using them.

Andy

 

[Vinylsavor]

Hi!

Different types of filaments also respond differently IME. The 801A / 10Y family the most. Also the further upstream in the signal chain the more critical it get's.

In a linestage a 801A can sound anywhere from unbearable to absolutely wonderful depending on the filament supply. But worth the effort IMHO

Thomas