I agree that Andy is great to deal with. You have to call him since he doesn't check his email.
If your Amperex sounded rolled-off, then they were dying or defective. Amperex, especially Bugle Boys have deep bass extension, liquid smooth mids, a 3D soundstage. They do have extended highs, however.
I would recommend RCA based on your needs.
Upscale Audio...
https://www.upscaleaudio.com/collections/preamp-tubes/6922-6dj8-7308-pcc88?page=1
Andy at Vintage Tube...
616-454-3467
If your Amperex sounded rolled-off, then they were dying or defective. Amperex, especially Bugle Boys have deep bass extension, liquid smooth mids, a 3D soundstage. They do have extended highs, however.
I would recommend RCA based on your needs.
Upscale Audio...
https://www.upscaleaudio.com/collections/preamp-tubes/6922-6dj8-7308-pcc88?page=1
Andy at Vintage Tube...
616-454-3467