[Amps] Filament voltage regulation

[MorgusMagnificen at aol.com]

Interesting that this recent discussion of filament supply regulation is 
taking place at exactly the same time that I have a new amp project under 
way. When I went to the parts cupboard for a filament transformer, the 
cupboard was bare! So rather than go out and actually buy a transformer (it 
is mind boggling how much those have escalated in cost) I have decided to 
build an electronic regulator and use a non-standard low voltage transformer. 
I will use a full-wave triac bridge with a zero-crossing integral cycle duty 
cycle controller for virtually noiseless switching.

The whole thing will fit on a small PCB of very user-friendly construction. 
If I could get a small handful of interested people to join me in this 
project (particularly those of you who have amp projects going now, or wish 
to upgrade previous one) I will make a first class commercial grade PCB with 
copies for everyone. The estimated parts cost will be under $10 (probably 
under $5, depending on your filament current needs.)

If you are interested, send me an email with your filament voltage/current 
needs. If I get a critical mass of volunteers, I will be able to do the whole 
thing in 10-15 days.

Eric von Valtier  K8LV