Change EL84 tubes on Eico HF 81


How can we biaset on quad El84 tubes on Eico HF 81. Please explain or give procedure how to change tubes. I am new tube amp. I want to buy 4 quad Mullard Russian EL84 tubes to replace old Russian tubes. Thanks again for your help
sanjose_audio_guy

Showing 2 responses by sanjose_audio_guy

For Eico HF81, new "matched" quad Russian of EL84's you simply plug them in... The HF-81 is a cathode biased amp and requires reasonably matched pairs per channel. A matched quad is even better. No adjustments required either way. I found answer from people who are current using HF81
David. Thanks for your infor on substituting old stock el84's for the modern Russian equivalents. How can we check the cathode resistance to 180 ohms? I will buy brand new quad EL84 Russian Mullard tubes. Can you give me detail on measure on EL84 tubes?

Regards and Merry Christmas

TH