My full review of the RAY 6SN7 Select vacuum tubes by APOS Audio, using the Feliks Audio Elise Headphone amp.
Available only at APOS Audio... https://apos.audio/products/apos-ray-vacuum-tube-6sn7-select?_pos=7&_sid=544b434b5&_ss=r&variant=44198665060588&sca_ref=437799.1pIW9B8scH
0:48... Details and Specs.
5:42... Equipment Used.
9:24...Testing method.
14:20... Sound and comparison.
19:02... Conclusion.