Help Needed : Tentlabs DC Filament Supplies

[Ratcatcher]

Hopefully someone out there can give me some help before I blow my amps up.

Ive added some offboard Tentlab modules to my amps ( heres a link to the original thread : http://www.hifiwigwam.com/showthread.php?73653-211-valve-DC-heater-supply) I decided to take things a little further and use a separate mains tranny for each pair of modules (211 parallels). Output measures well and ive set the voltage at a smidge under 10v at the valve base tags.

Next stage is to turn the amps on and reset the bias. Unfortunately I now seem to have ac across the bias resistor and cant measure it to adjust. Anybody have any ideas?

 

[grazie]

Not sure if this is an information or implementation oversight. 'Mains tranny'=transformer?

You have rectified the output from the new transformers (AC to DC)?

 

[rabski]

Send Coco a PM, as he's more in tune with this that I am.

The Tent boards do not need DC IIRC. They have rectification built in.

AFAIK, however, you definitely need to use a separate supply for each board. I mean, each. Common supply to two is no good. Each has to be totally isolated, as the whole point is that the filament needs to be floating in respect of everything else. You cannot combine one traffo supply into two filament boards.

 

[mr.gregdee]

Hi Graham

please clear you pm box