aerodyne: Wrong rectifier tube

The UR3 mentioned in tube list is obviously not correct. This is older (sidecontact base) pentode, not rectifying diode.

There is not other UR3 tube in rm.org, but exists tube UR3C (rectifier). Should this radio has UR3C in tube list, or should be another UR3 created?

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The service manual that is uploaded to the model mentions a VR2 rectifier valve, but even this seems a bit strange, i cannot find any possible rectifier valve with this designation. Probably it is in fact an UR3C although the schematic symbol is a bit simplified, it does not show the independent cathodes.

Maybe some owner of a set could check the wiring to the valve holder to see if it is consistent with the UR3C pinout, even if the valve itself has no readable marking.

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I think the description VR2 is just a synonym like used for the other tubes V1, V2, etc. The real type no. for the rectifier tube is nowhere shown. It could be the UR3C or the UR3 P8A. But this is just assumption. May be someone has the radio and can check the rectifier type.

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I too think VR2 isn't a real part number, unless it was "in house" labelling by Aerodyne. The service info clearly states a "full wave" rectifier, but as it's a universal AC/DC model with no doubler or tranformer the schematic does show the two anodes in parallel as expected.
There is no UR2  or UR3 mentioned.
Connections listed
1 Cathode 1
2 heater
3 heater
4 cathode II
5 anode I
6 blank
7 blank
8 anode ii

That does correspond to the Mullard UR3C on RMorg, except my info is that UR3C is a B7 pin base,  and the service info says all Mullard (=Philips from 1928).

However the set is 1934 and the UR3C is later?

My 1944 Trader year book has Curlew as available in 1935 at £0 19s 6d 
Valves are VP13 met, SP13 met, Pen26, UR2 rectifier and Phillips C1 baretter. RMorg has no data on the UR2.
The Vidor CN213 seems to have the exact same list, with CY1 or CY2 as UR2 alternatives.
The CN213 is Trader sheet 725 (a reissue) but has a UR1 listed (single anode and cathode), though schematic shows two anodes and cathodes! However the CY2 does have two anodes and cathodes and matchs the video schematic and the Curlew pin connections above. However later in the text they have "V4 was changed from UR2 to UR1 though where the chassis is wired for a UR2, either type can be used, because pins 1 and 4 (cathodes) are joined together, as are also pins  5 and 8 (anodes) on the holder. Cy1 and CY2 can also be used as direct replacements"

The same Trader yearbook also has the Vidor CN213 Universal receiver: VP13 met, SP13 met, Pen26, UR2 rectifier and Phillips C1

The 1950 Mullard replacement guide for the Aerodyne Curlew (and Kingfisher) has VP13A*, SP13* PEN26 CY2

I have the Mullard 1935 Master Selection Guide. It does not have the CY1 or CY2, but does have UR1 (halfwave) and UR2 (fullwave).

The Mullard Valve and Service Guide 1946 has a UR3C and it's a 7 pin, but otherwise separate anodes and cathodes. It doesn't have the UR2 or CY2.
The UR1C is half wave, I think B5 base
The CY1 is half wave on the P8 edge connect

The UR2 seems the most likely rectifier by Mullard, so VR2 is a typo. Data is scarce (mullard price in catalogue) but it has the connections listed. It's also listed at www r-type . org, but the "PDF data" is merely one of the catalogue pages I have.

Before 1943 it was replaced with pin compatible CY2, or if socket is replaced with the 7 pin UR3C Trader sheet 641, Oct 1943, Mullard valve replacements. The CY2 is also replaced with UR3C and socket change to 7 pin. The CY2 and UR2 unobtainable by 1943.

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My conclusion is that it was a UR2. Example models might have UR1 (not UR1C), CY1 or CY2, or if socket is changed  later to B7 from P8, then a UR3C.

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There is a UR3 rectifier (equal to CY2) tube marked as UR3_P8A-Topf. I really don't know why I dont find it earlier. So it looks thet someone creating this model don't realised that there are two UR3 tubes - Mullard diode and Oxytron pentode.

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The UR3 isn't in any Mullard catalogue I have, but the B7 pin UR3C is. There may have been a Multard UR3 (P8A/CT8 base), but more likely only Philips and 1935, but too late for Curlew. The 1944 Trader catalogue lists the Curlew, Kingfisher (same chassis) and similar Vidor 213 as UR2. The Trader sheet for Curlew  obviously has VR2 instead of UR2 as a typo. It also identifies the valves as all Mullard, though the Barretter C1 is listed as Philips in the catalogue.

The CY1 and CY2 would also not have been available durling development as they are allegedly later redesigned UR1 and UR2 given the C to reflect the 200mA series heater.

Due to the war 1939-1945 for the UK, many 1935-1939 models later had alternate tubes fitted, often with the valve socket changed. There were various guides published 1943 to 1946 listing replacements, especially  P8A/CT8 to International Octal. It certainly seems strange that though the P8A/CT8 base was used up to 1941 that already before 1939 some  valves changed from P8/CT8 to B5 and B7.

The only UR3 data sheets I find are actually for the UR3C, the B7 base version. Also see  www (.) r-type.org/exhib/aaa1690 (.) htm 

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