19-04-2018, 07:26 AM
(This post was last modified: 19-04-2018, 07:26 AM by Murphyv310.)
Hi.
There seems to be far more diversity of valves used in US FM sets than in the UK. The Chapman uses an ECF80 & EF80 in its FM front end and a Philips AC/DC FM radio I have from around 1958 uses two UF80's.
The norm though would be an ECC85 or UCC85 with near universal usage in the UK. the *CC85 were less than reliable though with them gradually loosing emission until sensitivity fell away or they just stopped, this is reflected now in them being expensive for NOS stock. The ECC88 and even the PCC88 will work in place of the 85, some realignment is usually required but it's a good replacement with a noticeable increase in sensitivity, they also last well. The PCC88 will be slightly under-run on it's heater to be fair but it is possible in some sets dependent on the heater wiring to to add a bridge rectifier with 4 Schottky diodes and a smoother cap to supply the heaters with 7 volts DC, there is also a PCC85 which of course has the same characteristics as the ECC85 bar heater requirements.
There seems to be far more diversity of valves used in US FM sets than in the UK. The Chapman uses an ECF80 & EF80 in its FM front end and a Philips AC/DC FM radio I have from around 1958 uses two UF80's.
The norm though would be an ECC85 or UCC85 with near universal usage in the UK. the *CC85 were less than reliable though with them gradually loosing emission until sensitivity fell away or they just stopped, this is reflected now in them being expensive for NOS stock. The ECC88 and even the PCC88 will work in place of the 85, some realignment is usually required but it's a good replacement with a noticeable increase in sensitivity, they also last well. The PCC88 will be slightly under-run on it's heater to be fair but it is possible in some sets dependent on the heater wiring to to add a bridge rectifier with 4 Schottky diodes and a smoother cap to supply the heaters with 7 volts DC, there is also a PCC85 which of course has the same characteristics as the ECC85 bar heater requirements.
