Its interesting to see one of my designs posted here
https://www.vintage-radio.net/forum/...d.php?t=102751
Even posted by Andy in his quest for a phono stage. The second design in the link was specifically designed for a US client. hence the transformer in and out. The 6BR7 is slightly better on noise than the EF86, but even better is the CV4006.
(6BR7 and CV4006 are the same pinout, but are different to EF86)
The 6DE7 is a dissimilar dual triode. The first triode is roughly equivalent to a 12AX7, and the second stage is roughly similar to a 12B4. Its design was originally for the vertical oscillator and vertical output for B/W TV receivers. I used it because it has the gain required to re amplify the output from the pentode after RIAA correction, and the current drive to work the output transformer.
The input stage using the CV4006 followed by a 12AX7 is the phono stage I listen to every day, and is incorporated into my little 7 watt/channel 6BW6 amplifier.
The phono stage ( to be an audiophool) is extremely smooth and pleasant to listen to.
Its DC heated, but incorporating it into the power amp box, even with a thick steel screen between the phono stage and output stage + power supply is NOT the quietest way to do it. At full volume I do have a little hum but its inaudible at "normal" listening levels.
Joe