Hi,
I am comparing the effects of having a regulated DC filament supply for my DIY preamp, loosely based on C22.
There are 5 tubes in this pre-amp. Three for audio and two for power supply.
As I have 9Vac and 6Vac outputs from my transformer, I used the 9Vac supply for 3 ECC83s for audio and the 6Vac for two tubes in power supply. The schematic is attached.
The 7ohm is to represent a load of 0.9A for three filaments connected in parallel. I am using 6.3V filament supply and each filament current should be 300mA.
I like the effect from converting the filament supply from AC to DC. So thought I could improve by having the supply regulated for the 3 Audio ECC83. The schematic is also attached. I am using a ST LM317 instead of the LT1085.
The results of regulation using the ST LM317, to my surprise, is terrible! No life in the music any all. Very unmusical! Flat and mechanical sound.
Does any one have experience with DC filament supply to share?
If I can change the voltage regulator to LT1085, would it be better?
Or is there any topology of DC filament regulation that would yield good sound?
Please help.
I am comparing the effects of having a regulated DC filament supply for my DIY preamp, loosely based on C22.
There are 5 tubes in this pre-amp. Three for audio and two for power supply.
As I have 9Vac and 6Vac outputs from my transformer, I used the 9Vac supply for 3 ECC83s for audio and the 6Vac for two tubes in power supply. The schematic is attached.
The 7ohm is to represent a load of 0.9A for three filaments connected in parallel. I am using 6.3V filament supply and each filament current should be 300mA.
I like the effect from converting the filament supply from AC to DC. So thought I could improve by having the supply regulated for the 3 Audio ECC83. The schematic is also attached. I am using a ST LM317 instead of the LT1085.
The results of regulation using the ST LM317, to my surprise, is terrible! No life in the music any all. Very unmusical! Flat and mechanical sound.
Does any one have experience with DC filament supply to share?
If I can change the voltage regulator to LT1085, would it be better?
Or is there any topology of DC filament regulation that would yield good sound?
Please help.