Suggestions for connecting with "Project Completers"

[miranker]

Folks,

I have a couple of projects which are defined up to reasonably detailed circuits. I am looking for someone to check/finish/improve the circuit-design, and do PCB design.
I am happy to take care of getting prototypes made - - -

Attached is one of these projects. It is to build a "universal" B-Battery eliminator for battery powered vacuum tube radio sets (~1920-1935). The idea is to use this in sets that have batteries inside the radio (so a large external box will is not really satisfactory). This circuit, plus 3 LiPo rechargebles should do the trick and fit anywhere.

Suggestions?

GSM

 

[rfs100]

Is there really that much call for a B-Battery eliminator. I would think that a ac llines powered unit would be more useful. Most people who have antique radios that were battery operated, and still want them ton work have already converted them over to mains power.

 

[miranker]

Don't Forget Portables

There were portable, tube battery powered sets and at least one collector (me) would like to install batteries that internally.

gsm

 

[peufeu]

A chain of voltage doublers isn't really efficient... why not use a type of switcher more suited to this (like a flyback, or even a simple inverter-style transformer) ?

 

[Nigel Goodwin]

A chain of voltage doublers isn't really efficient... why not use a type of switcher more suited to this (like a flyback, or even a simple inverter-style transformer) ?

Yes, such converters have been commercially available at various times in the past, using switchmode transformer type supplies, normally constructed in the footprint of the original battery.