ZMF headphones - Cayin Tube Headphone Amp comparison - HA 3A, 6A 300B MK II - collect them all?

DISCLAIMER: This is not a review - ZMF sells the Cayin amps here: https://shop.zmfheadphones.com/collec...

Check out the cool looking ZMF cables used in the video here: https://shop.zmfheadphones.com/collections/cables

The upcoming Caldera, and other current ZMF models are for sale here: https://shop.zmfheadphones.com/collections/stock-headphones

Cayin HA-300B Video: https://www.youtube.com/watch?v=AAwAuaTUIlE

Cayin HA-3A Video: https://www.youtube.com/watch?v=EBys7dwe864

This video is informational and should be viewed as such via the bias of ZMF selling Cayin products.

0:00 - 0:59: Intro
0:59 - 3:09: General Features among all three amps
3:09 - 4:12: OTL VS OTC Amps, transformers, are they better?
4:12 - 6:28: Tube Swapping Considerations; price, type etc
6:28 - 7:59: Functionality Differences, the HA - 6A is kinda special!
7:59 - 10:18: Choosing between the amps - Noise, Power and Timbre + More features
10:18 - 13:59: Sound Quality Characteristics, defining the amps and more tube talk
13:59 - END: Wrapping Up, conclusions.