Output Transformer calculation

[Williamblake]

Hello!

This must be the quadrillionst time this topic is coming up, begging your pardon.

I just got my hands on four identical OT from Telefunken Magnetophon 85. They are push-pull for two EL95s with 2.25 Ohm and 4,5 Ohm Output with RAA 10k (this is nicely printed on the transformer).

However i would like to use an 8 Ohm speaker.

I measured the turns ratio to be 1:44 and 1:61. So with an 8 Ohm speaker RAA is 15 kOhm.

What would you expect? Is this usable? Don`t guitar amps want to pass below the knee rather than above it anyway? Should i raise the supply voltage to better fit 15k? Maybe i should just try it with 4 Ohm and 8 Ohm load and see what happens?

Yes, it sucks being too stupid to draw a load line.

Regards,
Jens

[HotBluePlates]

... OT from Telefunken Magnetophon 85. They are push-pull for two EL95s ...

Stuff I find online says this model record player uses single-ended ECL82/6BM8.

Anyway, yes, you can probably use your 8Ω speaker load.  The expected impact could be higher screen current, which you might be able to offset with a (larger? added?) screen resistor.  The tradeoff will be a part-watt less output power, and maybe a touch more compression at high signal level.

[Williamblake]

Thanks. There is a SE and a push pull version.