Audio Symphonies pre owners, tube questions


Hi,
I recently purchased an Audio Symphonies Plus pre amp, and I have a couple quick questions about the tubes.

1.) The 3 input tubes come with metal caps over them. I contacted YS-Audio and all they told me was that they are used to help "quiet" the pre. I was wondering if anyone had noticed any diffference running the unit with them on, then off. Currently, I still have them on, but I would think that it would make some sort of difference (I know I could find out for myself by doing a listening test, but I figured I could get more info by asking here).

2.) I was told that replacing the 'stock' input tubes can make a dramatic difference in sound. I went ahead and purchased/installed some "New Groove", Mullard's before even turning the pre on. My question for this is, what about the 6x4 output stock tube? Should it be replaced too, and if so, what would be a decent brand to go with?

Thanks for your time,
Kevin
kld

Showing 1 response by jeffreybehr

The 6X4 is the rectifier, not output tube. I have NO idea if it has any affect on sound. The center 12AX7 is the 1st gain stage and is used in stereo. The left and right 'X7s are the 2nd gain stage and the cathode follower, separate for each channel.

I have some capacitor-upgrade notes I made when I had a Symphonies I can send you if you e-mail me at jeffreybehratcox.net but substitute '@' for 'at'.
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