I'm putting together a mono amp which will use three EL84's wired in parrallel to a single op traf.
I will probably use a 5U4 rectifier and a 6922 input tube. Will my 150mz (270V) Hammond power transformer be adequate for current?
I will probably use a 5U4 rectifier and a 6922 input tube. Will my 150mz (270V) Hammond power transformer be adequate for current?
Hey, anyone called Chevelle deserves an answer. Unfortunately you have not quite supplied all of the needed information. Looking through the Hammond catalog, I don't find a transformer that exactly matches your description. An amp with 3X EL-84 can draw anywhere from 120 mA to 200 mA. Most Hammond transformers are rated for a maximum DC output with a cap input filter. In this case a 150 mA transformer would be marginal. You can draw about 170 mA if you used a choke input filter. If you do this, keep the bias adjusted on the low side until you see how hot the transformer gets. A lot depends on available ventillation, and the intended use of the amp. If this is going to be a guitar amp, with the volume "cranked to eleven" a lot, I would look for a bigger transformer.
I would suggest going Push-Pull and just using a pair of EL84s, the transformer would be happier.
Otherwise give it a shot and see if it gets too hot- if it does, switch to a GZ34 / 5AR4 rectifier (less filament current) and use a separate 6.3V transformer for all the tube heaters...
Otherwise give it a shot and see if it gets too hot- if it does, switch to a GZ34 / 5AR4 rectifier (less filament current) and use a separate 6.3V transformer for all the tube heaters...
It's a Hammond 270FX transformer. I was planing on resistive coupling
with a 1K load resistor, 40uf before and 40uf after, using a 5U4 rectifier. This is what I was hoping to work with.
with a 1K load resistor, 40uf before and 40uf after, using a 5U4 rectifier. This is what I was hoping to work with.
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