• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

measuring dc offset in OTL headphone amp

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I've not managed to find a consensus on this, perhaps someone can chime in: is it more relevant (as in: will the amp damage my headphones longterm) to measure the dc offset with or without a headphone load connected?

Example: my OTL tube amp measures around a meandering few +/- mV unloaded, sometimes hitting 10-30mV and, with my DMM set to record min/max/avg over ten minutes or so, a peak of -300mV, although this was definitely a spike, it didn't slowly climb to, or fall from this value.

With a 600ohm headphone load connected, it's typically <1mV, peak of 5mV, per channel.

All measurements taken after the amp has warmed up for over a minute or two.

Which is the figure to be more confident with??
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.