Pye Valve Sets

Most of the Pye sets I have encountered have clearly been designed to give very good sound quality. I understand this is fairly typical of the company's products.


Baby Q Senior

Wavebands - MW, LW

Valves - 1A7G, 1N5G, 1H5G, 1C5G

Date - 1940

Status - Repaired for a customer

This battery portable set is a disappointment from Pye in terms of build quality. The chassis is a flimsy piece of tin, with an untidy mess of components crammed together on the rear. In the set I repaired, some of the faults were due to components, which were badly positioned and had become crushed when the set was assembled into its cabinet.

There was also a weird problem, which I concluded must have been a design error, and which required a modification to overcome. For full details of the repair, please see the Recent Repairs section. Despite this, the set performs very well. The sound quality is very good for a portable, no doubt largely due to the good-sized Goodmans speaker used.


DC Model (1933)

Wavebands - MW, LW

Valves - (see below)

Date - 1933

Status - Contributed description and photo

Nigel Hughes provided the photo and the following description:

The DC Pye had a mixed bag of Mazda valves with pretty illegible markings and I had no data sheet. Philip Knighton found a range of DC prefix valves in the Avo Valve tester handbook and, knowing the type numbers that had been produced, I was able to work out which of the near illegible markings had been which. I had to guess the valve type for the RF buffer stage because a DC2Pen power output valve had been substituted!

The line up I finally used was:

RF Buffer DC2SGVM
Mixer DC2SGVM
IF Amplifier DC2SGVM
Detector, AGC and Audio Amplifier DC3HLDD
Local Oscillator DC3HL
Power Output Valve DC2PEN

The valve heaters are a series string, with tapped dropper resistors. The HT supply is in parallel with the heater supply. I have made up a silicon diode power supply to feed both HT and Heaters, although the valves are indirectly heated and would probably work on AC.


Fenman I

Wavebands - MW, LW, VHF

Valves - ECC85, ECH81, EF85, EABC80, EL84, EZ80, EM80

Date - 1955 ?

Status - Contributed photo

This photo was kindly supplied by Stuart Bradley


Fenman II

Wavebands - MW, LW, VHF

Valves - EF80, ECF80, ECH81, EF85, EF80, EBC41, EABC80, EL84, EL84, EZ80, EM80

Date - 1955

Status - Contributed description

Mark Else provided the following description:

This must have been an impressive sounding set! It looks to have been designed for quality and performance right from the start. Its price reflects this. Judging by the photograph on the Service Sheet the table model looks distinctly ordinary. The radiogram version looks a little ostentatious however.

There's no lack of gain on the FM side. The internal (or external if desired) FM aerial feeds an EF80 pentode RF amplifier. The mixer oscillator uses a triode-pentode instead of the usual triode. The heptode AM mixer provides the first stage of IF amplification being followed by a common IF amplifier. From there the IF strip splits in two. The AM section is fed to the detector (a separate diode in the same valve is used for the AGC) whilst there is a further IF amplifier/limiter valve, just for FM. The AF output from the discriminator is then fed back to the triode section of the mixer/oscillator valve for AF amplification. This triode is also used for amplifying the gramophone pickup input.

Following a complex tone control stage (bass is switched, treble is controlled by a potentiometer) the signal is further amplified by another triode (AM also - this signal misses the FM/Phono first stage AF amplifier of course) and fed to a push-pull output stage which uses separate EL84 pentodes. Another triode acts as phase splitter. The AF output is then transformer coupled to no less than four speakers. Two of them receive the whole signal, the others are fed a bass cut version.

Power supply smoothing is extensive throughout the set, using four electrolytic capacitors. There are a number of circuit variations between the table receiver and the radiogram, but the foregoing holds true for both models. The 'Magic Eye' in the radiogram version is an EM34.

This photo was taken from the Past Times Radio website


MPU/40

Wavebands - LW, MW, SW

Valves - ECH35, EF39, CBL31, CY31

Date - 1940

Status - Contributed photo and descriptions

Colin Carmichael provided the photograph and the following description:

Probably one of the last sets made before the War. It gives surprisingly good results for a short superhet, especially on short wave. Good sound quality with loads of volume! It also has an 8 position tone switch. Like most Pye sets it is well made, reliable and well designed but rather bland.

After reading the above comments, Mike Izycky said:

Regarding the Pye MPU/40. The comment about the set being "one of the last before the war" is sort of half-true. The "/40" denotes a 1940 season set- dead easy to spot because they have four wavebands and octal valves. There was an earlier set called the MPU (the Universal version of the MP, surprise surprise) which came out around the end of 1938/beginning of 1939 and was only three wavebands- it also "suffered" with being a side-contact valved set.


P/B

Wavebands - MW, LW

Valves - S215VM, S215VM, S215VM, L2, PD220, W6, W2

Date - 1933

Status - Contributed description

Mark Else provided the following description:

Looking at the circuit diagram of this battery portable superhet from the mid thirties, one cannot help but feel one is looking at the circuit diagram of a much more modern receiver - save for the presence of the set's five valves. The reason is the metal rectifier detector which makes the set look almost like a transistor set from 30-40 years later. Why this idea never really caught on in the valve era is a mystery. Cost, noise, frequency response, distortion, volt drop, reliability, could have been the reason (if any of these were problems with metal rectifiers). A second metal rectifier - both were known as 'Westectors' since they were manufactured by Westinghouse - provides the AGC delay.

Valve use is a bit odd at the RF end of things. This may not be surprising since superhet production had only been going for ten years or so in any volume and designers might have been game for some experimentation. There is an RF amplifier in the aerial input stage and the mixer/oscillator is a tetrode. The IF filter features an inductor in place of the usual resistor. The IF is 114KHz.

Another similarity with transistor radio practice of the 1960's is the inclusion of transformers in the AF stage. This set has one between the volume control and the triode AF amplifier. A second transformer is used as a phase splitter, driving a double triode which is used as a push-pull AF output valve, transformer coupled to the speaker.

The 130V HT battery pack included an isolated 4.5V section which acted as a grid bias source. LT at 2V was supplied by a Pye, unspillable, celluloid free, acid battery.

The mixer/oscillator valve, V2, was a critical valve, often specially selected. Care also had to be taken preventing the valve screening (presumably connected to its heater) from shorting to chassis. This was necessary because the heater was at RF potential. It appears that originally, wire wound cotton covered resistors were used. Pye recommended changing these for 'modern' carbon types in the interests of improved reliability.


P28

Wavebands - 3xSW (16m, 31m, 49m), MW, LW

Valves - ECH35, EF22, EBL31, AZ31

Date - 1949

Status - Repaired for a customer

As well as the three SW bands, this set also features a five-position tone control switch giving various amounts of bass and treble cut. This is necessary for serious SW listening - a job at which this set excels.

Despite being a short superhet (having just three valves plus a rectifier), the set is surprisingly sensitive and selective. Given a reasonable external aerial, the SW bands are very lively. This makes a pleasant change from many sets that have a single SW band that does very little or is so cluttered that it is impossible to pick anything out. On MW and LW, the sound quality is very good.

This example was a repair for a customer. He retrieved it from a garage where it had been stored for over 30 years, and although the cabinet was in a sad state, the chassis was in superb order. The only repairs needed were the replacement of the dial lamps, restringing of the tuning drive and a replacement mains flex. I replaced the output valve grid coupling capacitor for reliability - although the original (and indeed all the wax-paper capacitors) was fine.


P43U

Wavebands - MW, LW

Valves - UCH42, UBF80, UL41, UY41

Date - 1951

Status - In my collection

This interesting low-cost set has the wavechange switch on the side of the cabinet. The set uses a frame aerial, which is mounted vertically at one end of the chassis. The loudspeaker is a good-sized oval unit and the cabinet is Bakelite (as opposed to one of the softer plastics used on some sets), so the set gives good sound quality for its size. The mains input is via a two-pin receptacle, similar to those used on Bush DAC90 sets.

The repair and restoration of this set is described in the Recent Repairs section.

The base is removable in addition to the back, so good access for servicing is available without removing the chassis from the cabinet. There was also an AC-only version of this set, model P43.


P75

Wavebands - SW, MW, LW

Valves - ECH42, EF41, EBC41, EL41, EZ41

Date - 1953

Status - Repaired for a customer

Although the styling may not be to everyone's taste, with two knobs on the front and one on either side, the sound quality of this set is very good. Pye have clearly put a lot of care and attention into this aspect of the design.

The main problem seems to be the failure of the decoupling electrolytics. Although the set may well work fairly well, replacing these capacitors will bring about a significant improvement in sound quality.

Interestingly, the set I repaired was missing one coil and therefore would not operate at all on SW. The former was there, with another coil in place, and there was no sign of any disturbance, nor was there any way the coil could have come adrift and fall off the former by itself. However it was certainly missing, and I can only assume the set left the factory that way. Fortunately, my customer was not interested in listening to SW!

This photo was found on the Internet somewhere, but I cannot remember where!


P76 and P76F

Wavebands - SW, MW, LW

Valves - ECH42, EF41, EBC41, EL41, EZ41

Date - 1953

Status - In my collection

If the P75 above is a very good set, the P76 is nothing short of excellent! If you are looking for a set for listening to MW or LW broadcasts, particularly music, you want this set. Aesthetically it is nothing special, but musically it is superb.

The set has a complex negative feedback arrangement, designed to tidy up the somewhat uneven frequency response of AM broadcasts - the bass and treble are boosted slightly while the normally excessive upper midrange is backed off just sufficiently to remove the shrillness. Give it a reasonably strong signal, and you will find that it gives a most natural and pleasant sound.

The main problem, apart from the same electrolytics as those mentioned for the P75, is damage to transformers caused by overheating. When the grid coupling capacitor feeding the output valve becomes leaky, the negative feedback removes most of the distortion so owners do not realise anything is amiss until the excessive anode current causes either the output transformer or the mains transformer to burn out.

The only difference between the P76 and the P76F is that the P76F has an internal frame aerial, whereas the P76 needs an external aerial.

I recently bought one of these sets (a P76F) for £10. The varnish is flaking on the top and elsewhere, so the cabinet will probably need refinishing. The speaker fabric is dirty, so it may need replacement if I am unable to clean it. I haven't tested the set yet.


P114BQ

Wavebands - MW, LW

Valves - DK96, DF96, DAF96, DL96

Date - 1955

Status - In my collection

I bought this set with a Perdio PR36 in the auction at the December 2002 Wootton Bassett swapmeet, for under a fiver. From a quick examination it appears to be complete and in reasonable condition, although it is very dirty.


Pye P115U "Piper"

Wavebands - MW, LW (pretuned to 1500m)

Valves - UCH42, UF41, UBC41, UL41, UY41

Date - 1956

Status - In my collection

This is a cheap-and-nasty offering from Pye. The circuit is built on a rather flimsy PCB, and the set uses permeability tuning. LW is pretuned to 1500m - formally the home of the Light programme, and now BBC Radio 4. The cabinet is made from thin curved plywood - mine has a crack on the top right. The "throw-out" aerial consists of a few feet of wire - no ferrite rods or frame aerials here! The set cost just 7 in 1956, and was clearly aimed at the second-set market.

My repair of this set is detailed in the Recent Repairs section.


P131MBQ

Wavebands - MW, LW

Valves - DK96, DF96, DAF96, DL96

Date - 1955 ?

Status - Repaired for a customer and one in my collection

This is a mains/battery set which, as expected from Pye, gives very good quality sound for this style of set. The mains input is via a two-pin connector the same as those used on Bush DAC90s etc.

The mains power supply uses a transformer, which results in a more reliable set than those using dropper resistors. Having said that though, the set I repaired had an open-circuit secondary winding on this transformer, as well as a faulty metal rectifier and an open-circuit output transformer primary! The output transformer was replaced with a vintage RadioSpares replacement from a scrap set. The faulty winding on the mains transformer was one half of the centre-tapped HT winding. However, using a single silicon diode (with suitable series resistor) to half-wave rectify the output of the remaining section of the winding, gave completely successful results. I was expecting the hum level to be excessive, but it was barely audible. This is probably because the HT supply is smoothed with two 32uF capacitors - more than ample for the 12mA or so HT current these sets consume. The only other work required was the replacement of a few leaky capacitors.

The service data I have appears (from the reference number) to have been printed in 1955, so this is my best-guess as to the date of the set.

I have recently been given one of these for my collection by Jon Evans. He had rescued it before it was chucked in a skip in London! It is missing the brass trim from two knobs and all the valves. Someone has removed the mains inlet connector and connected a cable in directly. I haven't investigated any further yet.


R31 "Caprice"

Wavebands - MW, LW, VHF

Valves - UCC85, UCH81, UBF89, UABC80, UL84, UY85

Date - 1959

Status - In my collection

It has to be said that this is not one of Pye's best efforts. Details of my recent repair of one of these sets is included in the Recent Repairs section. The same chassis is used in another Pye model, the R37 "Rancher" (below).

It is not that clear in this photo, but the "Caprice" name is printed on an insert fitted into a hole in the case below the tuning scale. This suggests that the same case is used for a different model having piano-key switches. Can anyone confirm or deny this?

I have recently obtained another example of this set, this time in a grey coloured cabinet. I will add a photo in due course.


R37 "Rancher"

Wavebands - MW, LW, VHF

Valves - UCC85, UCH81, UBF89, UABC80, UL84, UY85

Date - 1960

Status - No longer in my collection

This set uses the same basic chassis as the R31. An extension piece is fitted onto the front of the chassis to allow the volume control to be moved further over and to give a longer tuning scale. I assume the drum on the tuning cap is a bit bigger too.

Although this looks like it is intended to be a high quality set I do not think it is up to Pye's earlier standards. The sound quality from the single elliptical speaker is nothing special, and the performance on the VHF band leaves a bit to be desired.

I also think the control knobs look too close together. It looks like a small chassis in a big case - which is exactly what it is.




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Last updated 14th April 2006.