Sky Queen anomaly

[boater sam]

I have a Ever Ready Sky Queen radio on the bench.  Serial number Q770408.  Looks to be an early Mk1 type with the basket weave speaker grills on both sides.

Arrived with a home brew battery eliminator installed -- badly.  I sorted that and made it safe. Filament voltage a bit high so a resistor in series just to be sure that the valves survive. The valves have probably been over run. All the filaments are still there.

The radio doesn't work, no surprise, its 70 years old.
No audio at all, power is getting there and the output transformer is OK.
So I check around the output valve, utter confusion, it is not wired for the correct DL96 valve but for a DL92.
The paper label in the cabinet says DL96, all the other valves are Dx96 series.  Looks as though it has never been altered or repaired from new. All the old caps are present.
But, yes, a DL92 is fitted. A Mullard one. The others are Ever Ready.

I think it is no emission, it has both halves of the filament.

Has anyone come across this use of this wrong valve from new before?  Did Ever Ready run out of DF96 valves?

[Mike Watterson]

Someone has swapped a DL96. Makes no sense as the DL96 was and is more available and 1/2 current. A DL94 is same filament as DL92 and twice power.

The last version of the Model T before the original style Sky Queen even moved to Dx96 valves. It's rare. The Model T is actually very similar.

Ever Ready valves were Mullard/Philips even before WWII, except for a few 1930s models using Mazda.

I've several variations of T as well as all three main types of Queen (only one is like T) and the related King, Prince and Lord.

Edit See notes here
https://www.radiomuseum.org/r/ever_sky_queen.html

And very last and very rare Model T (1953) like early Sky Queen using DK96 DF96 DAF96 DL96.
https://www.radiomuseum.org/r/ever_all_d..._t_sq.html

Even the Model T before that used from Serial No. 544750 the DK92 DF91 DAF91 DL94.
The 1950 version Model T used the DL92.


Don't even power on old sets like these without replacing at least Anode/Grid paper caps and any TC from anode to 0V. The O/P transformers die quickly if the O/P valve works.

[boater sam]

Understood and agreed.

But this set has never been touched, the wiring on the valve base is all original.

[boater sam]

The connections are different between DL96 and DL92 valves. They are not interchangeable.

[Mike Watterson]

Understood and agreed.

But this set has never been touched, the wiring on the valve base is all original.

I know the DL92 & DL96 don't swap. I've a house, attic and workshop full of these and my first battery valve set was a Lady Margaret in maybe 1966, though I was clueless then.

I knew a BBC lecturer that could change stuff and make it look original.
If it's old and done professionally how would you tell if it was factory or in 1954-59 by a talented repair guy that had a DL92 in stock and no DL96? That's the logical explanation, a repair guy and customer wouldn't wait for replacement DL96.

It's less believable that it was done in the factory, for several reasons, and if done in the factory it would be re-work anyway, not likely original.

[Mike Watterson]

Probably you know, but recommended LT is 1.35V, +/- 10% (Mullard/Phillips data), but 1.33V and +/- 5% is better for mains.
HT of 75 to 85V is fine.
The 1.5V and 90V are nominal not quite fresh Zinc-Carbon voltages with about 1V to 1.1V the LT end point (DK9x stops oscillating) and about 60V the HT end point (1.0V per cell average).

I use alkaline AA for HT and Alkaline D cells in parallel for LT except on sets where that doesn't fit. Can't see any point to battery eliminators now as the radios are only for demo, pointless for everyday listening (especially here now that RTE is gone from LW as well as MW, though most of the battery valve sets I have from 1929 to 1961 do get R4 LW during the day and UK MW from dusk. A few have SW.

[boater sam]

Changed the DL92 for another, now I have audio from the detector.
The DF96 is dead, no IF amplification. Not got a spare.
The local oscillator is running.
Restuffed the electrolytic whilst I was thinking.

It all looks original to me, see the pix but I cannot post on this site.

[Mike Watterson]

Stuff can look totally original and not be!

I've used Russian 1j24b rod pentodes on home made adaptors to replace all the B7G battery valves on parallel LT. An added 1N60 as detector and 1/2 filament 1j29b for DL96 and both for DL94.
Two 1j24b for DK types, one as pentode mixer (signal g1, LO g2) and one as triodised osc with anode driving pentode g2, direct coupled.
The DF9x replacement needed a pull down resistor to set g2 (g2 volts sets gain).
Disadvantage is there is no RF or IF agc because of sharp cutoff.
I probably have stock of all B7G battery types now except IL6. A DK92 has similar performance, and works in socket, but HF alignment madly bad. So I started to do a version of the dual 1j24b mixer/osc with ballast resistors for 50ma Series and trimmer caps as the 1j24b is much lower capacitance on anode and all grids. The MW/LW replacement is no issue as you can tweak the IFs, but mimicking the anode Capacitance avoids that.

The Sky Queen (and all the similar chassis) work well. I think good Q IFTs and well matched not too small loop aerial.

[Paul_RK]

Looks to be an early Mk1 type with the basket weave speaker grills on both sides.

Sounds curious, I've seen an awful lot of Sky Queens in my time but nary a one without an expanded metal front grille. I'm wondering whether whoever put in the battery eliminator changed the grille to non-metallic as a safety measure: and maybe rewired the set for the DL92 as a fix for the eliminator delivering a tad too much LT.

Paul

[boater sam]

Looks to be an early Mk1 type with the basket weave speaker grills on both sides.

Sounds curious, I've seen an awful lot of Sky Queens in my time but nary a one without an expanded metal front grille. I'm wondering whether whoever put in the battery eliminator changed the grille to non-metallic as a safety measure: and maybe rewired the set for the DL92 as a fix for the eliminator delivering a tad too much LT.

Paul

Front and back speaker type grills are the same heavy fabric basket weave similar to the Goblin Time Spot  material. Definitely original, stapled and glued in.
The more I look at the components and wiring to the valve bases the more certain I am that this is all original.
There is a loop of thin insulated wire on the DL92 valve base between pins 2 and 6 which is the same wire but green instead of blue that is used elsewhere in the set. This would never have been there if it was wired for a DL96 as pin 6 is the signal grid.