pye: P131MBQ;

ID: 292022
This article refers to the model: P131MBQ (Pye Ltd., Radio Works; Cambridge)

pye: P131MBQ;  
03.Jul.12 17:03

Michael Watterson (IRL)
Articles: 1064
Count of Thanks: 8

This model succeeds the  Pye P31MBQ mains/battery portable which used x2 LT (50mA @ 7.5V vs 25mA @ 7.5V).

Original Pye Jewel Case

This is the first portable set Pye released called the "Jewel Case". It may have been variously advertised as "P131MBQ" or "Jewel Case"and called "Jewel Case" on Pye Service sheet (early 1955 ior maybe late 1954). The second "Jewel Case" P114BQ also marketed as the  "Jewel Case" and called "Jewel Case" on Pye Service sheet (early 1955 ior maybe late 1954). It's a larger cabinet (styled similarly) using a chassis with integral mains power supply, "tag strips" and "Point to Point" wiring. This model (P114BQ) is one of Pye's first PCB based sets. The P114BQ also has the chrome steel panel, but otherwise is different with dial cord and linear scale. The Chromed steel panel on this Mains/Battery model also serves as a "head sink" for the LT supply HT dropper resistor. The Marconiphone/HMV mains/battery models all suffer scorched/melted fabric above the dropper resistors


Cost Reduction?

The P114BQ is the battery only version in late 1955 using a PCB instead of "point to point" wiring and tag strips. No drive cord or geared/slow-motion tuning drive (The later Vicki / Vicki 26 / Invicta 26 from Pye does have a nice geared tuning drive). It also uses 1.5V @ 125mA parallel filaments instead of series.

The later  Invicta 28 from Pye is identical chassis to P114BQ as is the PAM712 ( The Invicta 29  PAM 716 is also same chassis and Mains using a sub chassis (not an updated  Pye P131MBQ "Jewel Case")  and a three way switch on same cabinet. The Mains on these later models uses a separate LT winding and Metal rectifier as primitive regulator for the 1.4V LT.

The battery only Invicta 28 and battery only PAM712 only  differ to P114BQ in case (cabinet design) and year of manufacture. The Mains versions unlike Pye P131MBQ (Mains /Battery Jewel case, no PCB, vs "Jewel Case" P114BQ) are just the  battery only models with an extra Mains subchassis and extra switch on same case and front panel. See Invicta 29 and PAM716

(The Pye  PAM710 was unrelated, being the first UK transistor set)

Pye strangely didn't put model plates on most Battery Portables.

Even the "Maker" name is understated

  • Pye Models: Small round Pye badge
  • Pye Invicta Models: Prancing pony on small round badge
  • Pye Pamphonic Models: Small badge with PAM or larger badge with Pamphonic

Just for completeness, the Pye P31MBQ (Mains+ Battery) and Pye P31BQ (battery only) appear to be the predecessors to this range using the DK91 DF91 DAF91 DL92 tubes but with geared tuning drive unlike P114BQ, Invicta28/29 and PAM712/716. (all DK96, DF96, DAF96 and DL96),

Perhaps the "P131MBQ" Mains/Battery "Jewel Case" was the last Pye "conventional chassis" portable and the  P114BQ the first Pye PCB type wired Portable?

Performance both on this model and the P114BQ, Invicta 28 and the  Invicta 29  is excellent. The Vicki / Vicki 26 / Invicta 26 is a different design and style of case with a very small ferrite rod aerial instead of loop. 


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