The Right Cost Affective Trannie

[IRON AND GLASS]

DIY Friends, If You Please, A Question: What's the the most cost affective brand & model of transformer that will deliver an adequate heater supply to (8) 6AS7's rated @ 6.3V - 2.5A. I do not want to to use or waste any other robust trannies that I already have and need for other projects. So if You would Please bestow some of Your Prowess upon Me, I will be most grateful. Your help would most certainly be appreciated. Thanks

[AndrewT]

buy a dedicated heater supply transformer.
Get it rated for 2times the AC current you require or if you are going for DC heater supplies then rate the transformer for 4times the DC current of the heaters.
That way you don't have to select a mains transformer to do double or triple duty.

[bear]

Lesseee... 8 x 2.5A = 20amps @ 6.3v = >120watts = a big filament transformer.

Probably that would be a toroid, for ease of availability, especially one that has 2 x 6.3v windings, so you can parallel them...

And where in the world are you? One shipped halfway around the world may or may not be cheaper than one closer in...

Now 2x the current would be an ever bigger honkin' transformer!
So, no chance you'll find a B+ transformer with that sort of winding on it...
The easiest way to handle it might be to get a higher voltage transformer and regulate down to the requisite voltage... that makes for a cheaper and lower current transformer... but more parts and heat, and you need a crowbar circuit in case the regulator fails to pull the voltage down...

Or maybe even you could control the current and not the voltage... doubt that the heater will know the difference... dunno... seems to work on 300B tubes.

It's indirectly heated so you don't need to worry much about HV breakdown issues...

Ah, so the answer is: the one you find that you can afford!

_-_-bear