EL84 safe plate voltages

[TTL]

I did some tests on a 1Khz sine wave, and it lies around 12W for min volume and 13W on max. So if I connected it to my grid, it would be 13,5-14,5W.

Alan4411: It's a Lafayette LA-224B. Produced in Japan, ca 1965. Apparently it was not amongst the most expensive amplifiers, but I think it's gorgeous

 

[Alan4411]

It's a Lafayette LA-224B. Produced in Japan, ca 1965.

In which case I would not worry about the EL84s being 'over run' or the mains transformer unduly.
Have a look at the schematic, the transformer is rated at 230 volts AC and the HT+ (B+) is quoted at 300 volts.

As it's 50+ years old and Japanese I would be more worried about the original grey 0.05uF coupling caps going leaky and that will damage the EL84s...

 

[TTL]

I've replaced all the caps, ceramics included. It's fit for fight and sounds nice 🙂

I see 230V in the schematic, but unit seems to say otherwise. I've attached a picture of the transformer. Could it be that it actually is a 230V unit, pretending to be 220V? 😕

With the lid off, at 220V, transformer shell stabilized at about 65C in the hottest areas.

 

[TG]

I see 230V in the schematic, but unit seems to say otherwise.

There was no 230V in the 1965.
230V is a compromise between mainland Europe's 220V and UK's 240V made in the 1990s.

 

[kodabmx]

If you take the RPM limiter out of a 1987 Volkswagen Jetta, you can rev the engine to 8,500 RPM . . .
The Life of Your Engine May Vary.

And we did! The redline of the engine in an 87 Jetta is the RPM where the power drops. It's a non-interference engine 😀

 

[TTL]

All my measurements have been at 220V. So it does seem, regardless, that using it with my mains is pushing it. I'm making a buck transformer for it now. If it makes too much noise, however, I might reconsider it.