Your amp is not working. You shouldn't be listening to it.
When you swap out a tube socket or other parts, you need to do a voltage check to be sure the amp isn't working, otherwise you may be sacrificing your headphones to learn whether or not the amp is safe to use.
You need to replace the LEDs and recheck the voltages and let us know if any are still not what they are supposed to be. If all the voltages check out OK, then you can listen to the amp.