02-04-2017, 04:30 AM
I might be able to answer my own question about the disposition of the four tuning capacitor gangs, using the chassis underside pictures in post #19. From the way the wires appear to run, it looks as if the two central capacitor gangs are associated with the middle of three coil boxes, from which one might reasonably deduce that contained therein was a bandpass tuned arrangement. Most likely the middle coil box is the interstage, between the RF amplifier and the mixer. The rearmost, close to the aerial input, would then be the RF input tuned circuit, and the forward most the oscillator tuned circuit.
I imagine that two valves between the coil boxes and the tuning capacitor box are to the rearward the RF amplifier (assumed to be a W77)) and forward the mixer-oscillator, known to be an X79. By the way, the original T99 would have been a very early application for the X79, which apparently was released in the latter part of 1951. That was also when the original T99 was released, in conjunction with the LF612 amplifier, for the Ether Conqueror Series V, which was a 1952 season model.
The valves on the left-hand side of the chassis (looking from the front) would include in the inner row a pair of W77 IF amplifiers, and a D77 demodulator and agc rectifier, and in the outer row probably a triode-strapped Z77 for the AF tone-control stage, and at the rear the gramophone input stage. The valve between those two, and adjacent to the D77 is something of a mystery. But perhaps the T57A case gives us a clue. That had a single W77 IF stage, and a D77 behind the second IFT can. Right next to and outside of the D77 was a DH77. Quite probably one of its diodes was used for agc delay. If the T139 is any indication, Dynatron preferred to separate the agc rectification and delay functions, presumably to avoid differential distortion. The triode might have had an AF function. But the T57A probably lacked the gramophone preamplifier, it had a four-pin socket marked “Pre Amp” which I’d guess was the power supply for an outboard gramophone preamplifier. The T57A appears to have been an update of the T57 for the 1954 season, used with the new LF48 amplifier in the Ether Princess P108. Both the T57 and T57A had three-gang front ends, with what looks to have been a “standard” three-gang unit. They had one shortwave band, and apparently lacked a tuning indicator.
The use of four tuning gangs in the T99 was evidently inherited from the T69D. The T69A (1946) and T69B (1948 or thereabouts) were three-gang, but had four-gang capacitor frames with one empty bay, rather like Eddystone did with some models. About the T69C I don’t know. One difference from the T69B appeared to be the addition of another valve at the left rear, quite possibly a gramophone preamplifier. I understand that the T99B at least had a this facility, and used a Z729, probably triode-strapped. The T99 and T99A also had a valve in this position, but what it was I don’t know.
The T69B had a changed faceplate as compared with the original T69A, with the tuning control shaft raised somewhat relative to the others rather than being on the same horizontal line. It also introduced some form of small circular logging/bandpsread scale around the tuning knob, which basic design was carried over to the T99.
The T99A appears to have arrived in the latter part of 1952, along with the LF612A, for the 1953 season version of the Ether Conqueror V. What changes were made I don’t know. The T99B is I think the version that was used in the Marconi Mimco 1155(A) (?) marine broadcast receiver, along with the LF512 amplifier, which was introduced in the second half of 1953.
The Merlin console receiver looks to have tracked the Ether Conqueror in terms of its tuner and amplifier complement, at least until the latter part of 1954. The B129 series had the T69x tuner and LF59x amplifier, and then the B1512 series were based upon the T99x and LF612x. The 1954 season version, as shown in the 1953 Radio Show catalogue, was the B1512E. Then for the 1955 season it was aligned with the then-new Ether Marshal chassis, which used the T139/LF613 combination, in which guise it was the R1712ME.
The Marconi Mimco receiver also went over to the T139, in this case with the LF512A amplifier, as the Mimco 2235(A).
The Ether Conqueror survived at least one season running alongside the Ether Marshal, but may well have gone before the 1956 season, as it was not listed in the 1955 Radio Show catalogue, which showed the Ether Pathfinder (T10/TC10/LF10) added and the Ether Marshal retained. From that one might deduce that the T99 production run was around four years.
The above is based mostly upon information found at various places on the internet, and interpretation thereof including interpolations and extrapolations. Thus for the most part it is not based upon original sources, and probably contains some errors.
Cheers,
Steve
I imagine that two valves between the coil boxes and the tuning capacitor box are to the rearward the RF amplifier (assumed to be a W77)) and forward the mixer-oscillator, known to be an X79. By the way, the original T99 would have been a very early application for the X79, which apparently was released in the latter part of 1951. That was also when the original T99 was released, in conjunction with the LF612 amplifier, for the Ether Conqueror Series V, which was a 1952 season model.
The valves on the left-hand side of the chassis (looking from the front) would include in the inner row a pair of W77 IF amplifiers, and a D77 demodulator and agc rectifier, and in the outer row probably a triode-strapped Z77 for the AF tone-control stage, and at the rear the gramophone input stage. The valve between those two, and adjacent to the D77 is something of a mystery. But perhaps the T57A case gives us a clue. That had a single W77 IF stage, and a D77 behind the second IFT can. Right next to and outside of the D77 was a DH77. Quite probably one of its diodes was used for agc delay. If the T139 is any indication, Dynatron preferred to separate the agc rectification and delay functions, presumably to avoid differential distortion. The triode might have had an AF function. But the T57A probably lacked the gramophone preamplifier, it had a four-pin socket marked “Pre Amp” which I’d guess was the power supply for an outboard gramophone preamplifier. The T57A appears to have been an update of the T57 for the 1954 season, used with the new LF48 amplifier in the Ether Princess P108. Both the T57 and T57A had three-gang front ends, with what looks to have been a “standard” three-gang unit. They had one shortwave band, and apparently lacked a tuning indicator.
The use of four tuning gangs in the T99 was evidently inherited from the T69D. The T69A (1946) and T69B (1948 or thereabouts) were three-gang, but had four-gang capacitor frames with one empty bay, rather like Eddystone did with some models. About the T69C I don’t know. One difference from the T69B appeared to be the addition of another valve at the left rear, quite possibly a gramophone preamplifier. I understand that the T99B at least had a this facility, and used a Z729, probably triode-strapped. The T99 and T99A also had a valve in this position, but what it was I don’t know.
The T69B had a changed faceplate as compared with the original T69A, with the tuning control shaft raised somewhat relative to the others rather than being on the same horizontal line. It also introduced some form of small circular logging/bandpsread scale around the tuning knob, which basic design was carried over to the T99.
The T99A appears to have arrived in the latter part of 1952, along with the LF612A, for the 1953 season version of the Ether Conqueror V. What changes were made I don’t know. The T99B is I think the version that was used in the Marconi Mimco 1155(A) (?) marine broadcast receiver, along with the LF512 amplifier, which was introduced in the second half of 1953.
The Merlin console receiver looks to have tracked the Ether Conqueror in terms of its tuner and amplifier complement, at least until the latter part of 1954. The B129 series had the T69x tuner and LF59x amplifier, and then the B1512 series were based upon the T99x and LF612x. The 1954 season version, as shown in the 1953 Radio Show catalogue, was the B1512E. Then for the 1955 season it was aligned with the then-new Ether Marshal chassis, which used the T139/LF613 combination, in which guise it was the R1712ME.
The Marconi Mimco receiver also went over to the T139, in this case with the LF512A amplifier, as the Mimco 2235(A).
The Ether Conqueror survived at least one season running alongside the Ether Marshal, but may well have gone before the 1956 season, as it was not listed in the 1955 Radio Show catalogue, which showed the Ether Pathfinder (T10/TC10/LF10) added and the Ether Marshal retained. From that one might deduce that the T99 production run was around four years.
The above is based mostly upon information found at various places on the internet, and interpretation thereof including interpolations and extrapolations. Thus for the most part it is not based upon original sources, and probably contains some errors.
Cheers,
Steve
