Outlet - Shunyata vs Hubble 20 amp

@jumia

The Shunyata SR-Z1 is a Hubbell HBL 5362 Extra Heavy Duty Specification grade 20 amp Duplex Receptacle.

Specifications
Face Nylon
Base PBT
By-Pass Power Contacts .036". (.9) Brass
Ground Contacts .031 in. (.8) Brass
Clamping Plate Nickel plated brass
Terminal Screws Plated brass
Mounting Strap .050 in. (1.3) Brass
Automatic Self-grounding Clip Stainless steel
Mounting Screws Zinc plated steel

https://www.graybar.com/hbl174-straight-blade-receptacle-duplex-extra-heavy-duty-industrial-20a-125v-2p3w-gray/p/88127181?pcode=88127181  

Shunyata - SR-Z1 AC Outlet - Music Direct

Hubbell makes a hospital grade outlet HBL 8300 for about $30-$40.

  Hubbell HBL 8300 20 amp Hospital Grade outlets  built in resent years are not good for the sound of audio equipment.

Specs for the deep body outlet:

Wiring HBL8300 Specification Sheet

Note: Contacts and supporting back strap are nickle plated. Both can cause graininess in the sound.

Slender/Compact design Hubbell 8300 hospital grade outlet.

Same problem. Nickel plated brass contacts.

.

The best one I found after trying many.....Maestro

So because of the nickel plating which causes graininess, The shunyata outlet made by Hubble it’s not very good. Heavy duty Hubble version it's only $30!!!

Very disappointing Shunyata would do this.

Hubbel is same as shunyata, so I'm not sure why it's different.

Where is the maestro outlet from, this sounds like it's better.