lissen: Possible configuration?

or Informed speculation?

This was one of the cheapest models on 28th September 1932 at the Manchester Radio Show. It would be reasonable to assume it's basically a battery version of the 2 valve mains model featured in November 1932 Wireless World.

That would mean it would have used an HL2 or similar for detector and PT225 or similar for speaker driver, probably Mullard made with Lissen bases.  There would have been three HT taps to save resistors and capacitors, the primary of transformer on HL2 anode, the screen of PT225 and the supply to speaker motor.

The top knob is likely the tuning with a 0 to 100 scale, middle wire to short LW coil for MW operation, lower knob the reaction. The 2V LT switch probably in the lower slot. The 120V tapped HT pack and 9V tapped GB pack would  not have been switched, to save money. Likely one grid leak resistor on HL2 and just two fixed capacitors, RF coupling to grid and RF decoupling on HL2 anode. Transformer (1:2 or maybe as high as 1:5) to couple the valves.

The aerial and earth wires via a cut out corner on back plate. The blocks to position the 2V Lead acid cell and standard tapped 120V dry cell battery pack can be seen on the  base of the case. I assume the tapped 9V grid bias pack clipped to the chassis, held by four screws to side of case with the control panel cut-out. There are no other mounting holes.

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Michael,

The Mullard listing for the following 2 valve sets of that period are

Popular  PM1HL and PM22A.

Colossus PM1HL PM2

8020  100 Station      PM1HL PM22A

Transportable 2   PM1A  PM22A

It may be that the originals were Lissen rebadged types.

It is unclear as to which model name the shown set relates; it probably is the Transportable 2 which has the similar mains Transportable 2 with an 354V and PM24.

Roy

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I agree the valves were probably "really" Mullard

Very many Lissen sets of that era used HL2 and PT225, which may have been PM1HL and PM22A or similar. Usually by 1932 a SG valve (RF tetrode) and extra tuning  stage is used. This was definitely a budget model!

Yes, the AC/HL is rebadged  354V and the 4 pin + side connection PT425 probably PM24.

The "Transportable" name may though have been just Mullard description as WW issues Sept 1932 and Nov 1932 for the battery, (wood), AC mains & DC mains (bakelite) don't call it that.

I think I saw a 8020 100 station illustration and the Colossus and this isn't it. 

It's likely the Transportable or the Popular.  I'd suspect a "transportable" would have a loop aerial. This can't have due to metal panel.

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