EL95 (EL95) EL95 substituting recommendations:

6BM5:
the best substitute for the EL95 is the 6BM5, as they are both pin compatible and have close ratings.
As a makeshift the EL95 can directly be replaced by a 6BM5 without modification. The 330 Ω cathode resistor of the EL95 will cause a small reduction of plate current and output power.

However, for a technically correct replacement by a 6BM5, the cathode resistor has to be changed to 270 Ω. Make sure, the plate current does not exceed 24 mA.

One should take into consideration that the heater current of the 6BM5 is 0.45 A, compared to 0.2 A of the EL95. Make sure, the power transformer does not overheat, particularly if more then one EL95 are replaced by 6BM5's.

EL42 and EL85:
they are the direct predecessors of the EL95. The socket needs to be changed, as well the cathode resistor has to be changed to 390 Ω.
One should note that they are designed to 225 V screen voltage, rather then the 250 V as normally. Make sure, the plate current does not exceed 24 mA.

EL90 / 6AQ5:
are less recommendable, since their rated plate current of 45 mA is almost twice the rated plate current of the EL95, which is 24 mA. One could choke down the EL90 / 6AQ5's plate current to 24 mA by increasing the cathode resistor, but this moves the tube into a non-optimal operating range with increased distortions.
As for the heater current refer to the 6BM5.

6AR6:
is also less recommendable, as it has a very low sensitivity and requires about three times the control voltage and negative bias. If someone wants to use it anyway, by all means the cathode resistor has to be changed into the range of ± 600 Ω, to let the plate current not exceeding 24 mA.

6AK6:
The 6AK6 should never be used as EL95 replacement, by no means and under no circumstances! The 6AK6 is fully underrated against the EL95 in several ways:

Plate and screen voltage: 180 volts (6AK6) versus 250 volts (EL95) = 72 %
Plate current: 15 mA versus 24 mA = 62.5 %
Plate dissipation: 2.75 watts versus 6 watts = 45,8 %

Operating the 6AK6 under the conditions of the EL95 is pure torture for this little tube.
Everyone will agree that someone who races at 80 km/h through the streets is a ruthless bully, when the speed limit is 50 km/h.
But when it comes to tubes, some radio collectors seems to ignore thoughtless any rules and limits. As long as no sparks fly or smoke rises, everything seems to be OK for them. Torturing tubes or other components by overloading doesn't matter at all as long as they last.

A conscientious radio restorer should not follow such inexpert recommendations.

 

To thank the Author because you find the post helpful or well done.