I do recall a design using the Bardwell transformer, Joe. I believe it was published in one of the magazines but can I find the original material? Nope. However, my rambling thoughts for what they are worth: transformers tend to vary rather (even from the same batch) and the high output under no-load conditions would, with some sets at least, drop to an acceptable level when the set takes its current. In cases of an annoyingly persistent high output, the two halves of the 45V winding could be paralleled and then the required HT voltage obtained via the bridge would be down to a more acceptable level, though below the 'standard' 90V.
Or, leave the full winding in circuit - both halves in series - and use half-wave rectification. This would need heavy filtering to avoid an objectionable hum level, though. I'd guess that the voltage, given good reservoir and smoothing, would be about the required 90V or so.
Of course, a regulator for HT isn't strictly needed. Good for precise voltage level settings, yes. One unit I built used a transistor as a regulator, along with zeners to set the levels spot on. For another unit I used quadrupling step-up (like a TV tripler in essence), only at 50 or 100Hz. This unregulated system works well, proving that regulation is something of a luxury for HT. I've actually used it for various power units including one for 2V filament valve sets.
I have in fact built several power supplies for battery radio use. (I like to tinker and experiment)
Tony
Or, leave the full winding in circuit - both halves in series - and use half-wave rectification. This would need heavy filtering to avoid an objectionable hum level, though. I'd guess that the voltage, given good reservoir and smoothing, would be about the required 90V or so.
Of course, a regulator for HT isn't strictly needed. Good for precise voltage level settings, yes. One unit I built used a transistor as a regulator, along with zeners to set the levels spot on. For another unit I used quadrupling step-up (like a TV tripler in essence), only at 50 or 100Hz. This unregulated system works well, proving that regulation is something of a luxury for HT. I've actually used it for various power units including one for 2V filament valve sets.
I have in fact built several power supplies for battery radio use. (I like to tinker and experiment)
Tony
