Re: Emiscope 3/16 Crt
Hello Peter. You must know how I like a challenge.. I hawked out two EMI receivers, A VC53DA, fitted with the 3/16 the Marconi version of the HMV1807 and the Marconi VRC52DA console fitted with the same television chassis as the HMV1805 employing the TA10.
To be fair it has been difficult to get a fair comparison from the pictures. The 1805 chassis is much easier to photograph especially displaying the considerable quality capable from the TA10. The BBC used them for monitors at AP.
The 1805 series takes a lot of beating from any angle and without doubt was EMI's best model by far.
The triode 3/16 fitted in the 1807 is a bit soft unfortunately and the other one I have fitted in a Marconi VRC54 has an O/C heater! Other than that the screen colour is similar but not quite the same. The 3/16s varied a lot and considering they were aluminised and operated at just under 5kv [for correct focus] it is not surprising they struggled. Some had a distinct sepia.
appearance.
It was EMI's first AC/DC tube and judging by the number of heaters that went O/C just outside the guarantee and the number of heater voltage changes during production, they were obviously having problems with it.
Some 1807 series were fitted with a modified COSSOR 108K 4 pin based tube that performed considerably better with a long life.
The TA10 is a tetrode and was fed with 7kv of mains derived EHT. It produced a pin sharp, black and white high contrast range picture.
Great to know you managed to get the 3/16 working in your 1805. It is probably being operated more closely to the requirements of an aluminised tube.
The pictures show the 1805, film and test card with the 3/16 test card at the end. John.
|