Glad that the Full Music 6SN7s worked out well for you, Ozzy. Your findings regarding their excellent sonics are consistent with many others I’ve seen reported for their Sophia counterpart. Including feedback Ralph mentioned earlier in this thread that he has received from a number of customers.
However, I’ll note for the record and for the information of those reading this thread that at various times in the past I and at least two other members here experienced totally unacceptable hum problems with the Sophia version of the tube. See my posts dated 4-2-2017 in this thread, and the link provided therein, and also the post in that thread dated 4-3-2017 by Tubegroover.
It can be expected that sensitivity of preamp and power amp designs to what I determined was apparently the cause of the problem (measurably excessive heater-to-cathode leakage, resulting from either a design defect in the tube or a quality control problem in its production) will vary widely among different designs. I would suspect that some designs will be totally insensitive to it. And FWIW, apart from the hum issue the Sophias did sound great in my amp.
Best regards,
-- Al
However, I’ll note for the record and for the information of those reading this thread that at various times in the past I and at least two other members here experienced totally unacceptable hum problems with the Sophia version of the tube. See my posts dated 4-2-2017 in this thread, and the link provided therein, and also the post in that thread dated 4-3-2017 by Tubegroover.
It can be expected that sensitivity of preamp and power amp designs to what I determined was apparently the cause of the problem (measurably excessive heater-to-cathode leakage, resulting from either a design defect in the tube or a quality control problem in its production) will vary widely among different designs. I would suspect that some designs will be totally insensitive to it. And FWIW, apart from the hum issue the Sophias did sound great in my amp.
Best regards,
-- Al