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The hum is 60 Hz or 120 Hz from the Power Supply.
Try to decide which. If 60 it may be filament voltage leaking to cathode or ??
Do you have access to a good tube tester. Do you have a 'scope?
If you have a 'scope look for hum on the cathode of the first tube.
If the hum is 120 hz it is on the V+ line. Since the diodes are new it should be a bad electrolytic cap.
Hmm...make sure all ground connections are good.
Hmm #2...since the music is playing so soft you may have an input wiring error or again a bad first tube or coupling problem.
What is the cathode voltage on the output tube?
Is it tube drawing too much current?
They were before the transformer was connected improperly
I think they were not getting any voltage before but am not 100% sure they did not see any reversed voltage or AC. Meaning one or more might be bad. We do need to clearly see how you wired everything, esp. the power supply.
"but i think it's 270V"
Cathode voltage, not plate.
@nigel i wish i could post a clear photo... believe me with all these
cables you wont understand anything...
That's why I asked for a picture, it should be all neat, tidy, with heater leads using twisted wires carefully run.
If you can't post a picture because it's so bad, that could well explain your problem.
You have great long wires connected to the right hand valve base, routed right next to the heater wires - wires need to be as short as possible and away from heater connections.
The higher the input impedance, the more chance of hum pickup - for a start short the input socket out and see if it's internal or coming in the socket.
The first hum is 100Hz from the full-wave rectifier. Maybe the filter capacitor is not good.
The second hum (buzz) is 50Hz and is picked up from the mains or from the filament wiring.
If you're using the original circuit you posted, then (like we told you) it's rubbish.
Add the decoupling components as shown in the two diagrams I posted, R5, R6, C1A and C1B in the second of the diagrams - without them you're just feeding hum from the PSU directly to the grids of the valves.