help me decide,headphone amp - parafeed or normal tx ?

[DualTriode]

Hello piano3,
I do not think that a chassis needs to be steel. I have not done a side by side comparison with aluminum. Aluminum works well. I have noticed on my bench where there were exposed power transformers and voltage regulators operating (a noisy world) that a ground (earth) lead attached to a line stage chassis made any audible noise disappear from the line stage.
DT
All Just for fun!

 

[piano3]

Yes DT, I agree and have done many experiments with different grounding arrangement. However as far as aluminium-vs- steel chassis is concerned, both are great electrostatic shields but only steel can give any(probably rather limited though) magnetic screening. I suppose an ideal chassis(and cable screening) would be non work hardened mumetal-that would really make some boutique components/transformers seem cheap.

 

[piano3]

This is probably a rather dumb question; in a transformer coupled headphone amp are the bottom of the output transformers commoned at the TRS socket and left floating or are they actually grounded? Thanks, N.A.

 

[regal]

Grounded. Otherwise if your primary shorts to the secondary you are looking at a few hundred volts across your head.

 

[piano3]

Thank you Regal-I had not considered this possibility-yikes!