The Eico ST40 has great transformers. The preamp section is very busy and requires many hours to refurbish. The 81 while only 14 watts is much less busy than the 40 and requires less attention but needs attention nonetheless.
Sound quality the 14 has the advantage but if you want quiet definitely the 14 unless you have someone modify or rebuild the ST40.
If you come across the HF14 which is the 14 watt monoblock you will be plesantly surprised. I once heard a pair driving a pair of Martin Logans. Interesting! I said it wouldn't and it did. What a suprise.
