Since Stontronics discontinued their 200mA and 400mA linear 18V regulated power supplies which were available from CPC, it's been hard to recommend a suitable battery eliminator for Hacker (and similar) radios which were designed to run from two PP9s in series.
Unregulated supplies have been tried, but hum seems to be a problem.
One solution is to use an 18V linear series regulator fed from a suitable scrap power supply that can found in most enthusiasts' junk boxes, or picked up from a car boot sale or charity shop for a pound or two. Printer and older answering machine ones seem to be most suitable in terms of output voltage.
These can of course be built on stripboard or similar, but if time is precious or one's soldering skills are limited, a ready-made module is a nicer solution.
I've found these, based on the tried and tested 7818 IC, from eBay seller
audiowind-2005 currently priced at a very reasonable
£6.90 including postage all the way from Hong-Kong:
http://www.ebay.co.uk/itm/Positive-N...item68d071aa16
A bare PCB can be had at £3.45, and other voltages (positive and negative) can be had. The seller also stocks other very useful power supply modules.
Quality appears excellent. The PCB is fibreglass and is screenprinted and components are apparently good quality (e.g. Rubycon 105degC electrolytics). Soldering is first rate. There's also an on-board LED. Input and output is via screw terminals, so ideal for newbies. A bridge rectifier is included but terminals are provided for the input to go straight to the regulator if preferred, so it can be used with an AC or DC power unit, making the choice of power sources quite wide.
They're also very compact, 2" x 2" x 1.5" high, so very easy to hide within the radio.
Delivery took less than 2 weeks all told. Packing was superb, the modules being supplied in a sealed antistatic bag protected by a stout expanded polystyrene box. No VAT or customs charges were payable because of the low value of the goods.
Thoroughly recommended.
Nick.