HAC Regen receiver PSU

[Malcolm T]

I am looking for a circuit diagram to build a power supply for the one valve HAC receiver, circa 1973. The HT is 90V and i think the LT was about 1.5V . Does anyone have any info or links please.

Many thanks

[unixmanuk]

Hi Malcolm,

I have one of these. They were originally powered from 1x 90V dry cell for the H.T., and a 4.5V cycle lamp type battery for the filament supply.

When the 90V cell became unavailable, I built a crude unregulated mains supply (transformer, bridge rectifier, choke and smoothers) that gave me about 80V that worked well enough for the H.T. side.

A google search for 90V Battery Eliminator will yield results for suitable schematics and ready made units

[snowman_al]

Hi Malcolm,
Which valve does your HAC have? If there is nothing on the valve, tell us how many pins it has on the base.
That will tell you / us what filament supply is needed.

I am looking for my HAC stuff, lost at the moment, but as I remember:
earlier ones had 2 volt valves and used 3 or 4.5 volt cycle lamp batteries and a series resistor. Later ones had 1.5 volt valves and run off a single 1.5 volt cell.

Alan

[Mr Moose]

Hello,
https://www.vintage-radio.com/projec...y-set-psu.html
Yours, Richard

[Chindit]

I had a one valve HAC set. It used the triode section of an army surplus AR8 (aka HL23DD). This is a 2 volt valve and the filament was powered by an Every Ready type 800 (the twin cell 3 volt bike lamp battery with the flat brass strip connectors) through a dropping resistor of around 8 ohms from memory. I bought a big Ever Ready B136 90 volt + 1.5 volt battery from Halfords to power it. I only used the HT section of course. This would be around 1974 and the battery cost me around £1.50 back then. I think the only other HT battery that was still available at this time was the smaller B126 which cost around £1.10.
Of course, seeing as the HT consumption is only a few milliamps, it would be easier to run it from 10 off PP3s daisy chained together in series and taped up. This would last for ages and would be true to the original method of powering the set.

[paulsherwin]

I would also suggest batteries. 10 Poundland PP3s will only cost £5, and you can use an alkaline AA from the same place to run the filament (I'm sure there are Poundland equivalents in Spain). It's surprisingly difficult to build a battery eliminator for Dx9x valves that doesn't introduce noise.

[Malcolm T]

Brilliant , thanks for the replies . I,m considering either a psu or batteries , either or , but definatly not switch mode !.
Its been in its box for years , last fired up in the early 80s and put away . Will get the valve number .

[Malcolm T]

I cannot find it yet but i recall the valve is painted gold , its in its box somewhere in another box !!!
A pity HAC went out of business it really was basement entry level into a fascinating hobby

[DAC10 Collector]

A battery supply will also be safer if you intend to use headphones with your HAC receiver.

[Cobaltblue]

A bit like this one maybe?

https://www.radios-tv.co.uk/communit...hort-wave-kit/

Cheers

Mike T

[Malcolm T]

Yes thats it . As for power batteries do sound safer option .

Thanks

[Chindit]

That gold valve is definitely one of the 2 volt filament types that were used in so many WW2 manpack sets. As I mentioned, my HAC set used an AR8 with grey metallising. This looks like an ARP12 pentode, as many of these were made with gold metallising and straight-sided envelopes. I don't think I've ever seen a gold, straight-sided AR8 - all mine are either grey or green.
I've still got the original valve and all the bits (including the octal-based Denco coil) - just need a new chassis! I must have 're-purposed' the original.
Certainly back in the 70s, noise levels were lower and, operated from batteries, these valves perform very well with a wonderfully silent background.
You'll find scans of various HT batteries on the net; they can be printed out, glued to a cardboard backing and used to make a very convincing reproduction HT battery that would be perfect for your set.

[Chindit]

Oops! Just had one of those 'foot in mouth' moments. Just enlarged the picture and I see it IS an HL23DD (AR8)! You learn something every day.

[Jon_G4MDC]

Better have good insulation on your headphones (In the anode supply if I recall).
Any deficient insulation and it will bite you hard.

[Malcolm T]

OOOhh i dont want that !.
Just looked at the circuit diagram and it shows it is in the HT supply , so maybe an audio amplifier as isolation might be better . I have original 2000 ohm bakelite and steel headphones and i think also a pair of very old BBC jobs.
Reading some of the history bumph it says there was an audio amplifier option.
How do these things cope with local electrical QRM ?.

[snowman_al]

Personally I would expect the 2k headphones to be the best option and in reality little risk. Especially if you use batteries.
If you are bothered, you could use a very small 220v to 6-0-6 volt 250mA mains transformer as an output transformer. It would need low impedance (30 ohms-ish) headphones though, then you could try either a 6 volt or 12 volt tap for the loudest output. It would also isolate the set if you wanted to use an amplifier.

[Malcolm T]

hmm ok , all good advice for the ideas dep,t
Thanks

[Herald1360]

Originally Posted by Malcolm T

How do these things cope with local electrical QRM ?.

No better and probably worse than a well screened set with a decent outdoor aerial (which you'll need to hear anything much).

Running on batteries away from houses will be a lot better.

[Malcolm T]

Well it will be interesting to get the set going again , i might even go /p on a hilltop .
hmmm We,ll see.

[David G4EBT]

This might be of interest to HAC fans - in particular some neatly made coils built into octal valve bases, and an 'HAC inspired' solid state design:

'The Sproutie' - 'A general coverage regenerative receiver with plug-in coils':

https://aa7ee.wordpress.com/2014/08/...plug-in-coils/