OTL Amp and Headphone impedance matching question

[White Lotus]

Is there a quick and easy way to determine if an amp is incorrectly matched to a headphone?
 
Other than hissing, an obvious roll-off, or volume levels that don't feel right (only needing a slight turn of the volume knob for it to be blaringly loud etc)?

 

[62ohm]

Does anyone know the output impedance of a 7236-powered OTL? Thanks

 

[GrindingThud]

In your WA3 it will be somewhere north of 80. Freq low end with HD800 will be pretty much flat to 11Hz.

 

[62ohm]

In your WA3 it will be somewhere north of 80. Freq low end with HD800 will be pretty much flat to 11Hz.

 
Cheers.