Brimar ECC804 and ECC807 double triodes
These are both rare valves, produced by BRIMAR
and
possibly Telefunken and Siemens, although that may be relabelling.
The data sheets are taken from the Brimar "Valve and
Cathode Ray Tube Manual No. 10."
ECC804
A general purpose double triode, μ=18,
designed for use in television receivers. Pinout is as ECC88/6DJ8 (not the same as
ECC83/12AX7,
i.e. there is a screen connected to pin 9 and no centre tap on the 6.3
V heater. Equivalent to 6GA8 and CV5264.
Characteristics
Curves
ECC807
A high μ (150) double triode, designed
for
use in high gain pre-amplifiers operating at low levels. It's
charateristics
are like an ECC83/12AX7 on steroids. It has about the same Rp (62500
Ω)
but 1.5× the transconductance (2.4 mA/V vs 1.6 mA/V). It is a
replacement
for the 13D7, but has higher gain. There are no direct substitutes. A
very
good ECC83 _might_ work in some circuits, especially if feedback could
be reduced and the heater was rewired . In other cases the best
replacement
might be two EF86's, which could do the gain easily, but would require
major surgery to the chassis. Otherwise the stages would have to be
redesigned.
It was used in the Rogers Cadet and the VTL
'Minimal'
preamp.
Characteristics
Curves
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