I ask that to my Siemens Seller and he said. ECC85 and E88CC is different voltage or something like that. But following link poster said it is good with Aune T1. So i wonder why.
May be i will take risk on RCA. RCA 6AQ8 ECC85 ?
Yeah, as far as I can tell the issue seems related to the fact that 6AQ8's have a higher current, but the heater in the T1 should handle it fine since the amperage rating on it is quite high.
There was a seller on eBay who guaranteed his tubes to work that I bought the RCA from, if it didn't work I would have returned the tube, I'll try and get his name later.