Please help...
I bought a custom built tube preamp. The builder shipped it with the tubes in the sockets...Electro Harmonix 12AU7's and a 12X4. Sounded flat and muddy. I had 3 extra JJ 12AU7's and put 1 in each channel. Sounded better so I got one more and replaced all 4 EH's. Sounded much better. Last night I noticed a high pitched noise coming directly from the preamp..not through the speakers. Can anyone offer and suggestions what the source of this noise is?
Thanks in advance....Blake
I bought a custom built tube preamp. The builder shipped it with the tubes in the sockets...Electro Harmonix 12AU7's and a 12X4. Sounded flat and muddy. I had 3 extra JJ 12AU7's and put 1 in each channel. Sounded better so I got one more and replaced all 4 EH's. Sounded much better. Last night I noticed a high pitched noise coming directly from the preamp..not through the speakers. Can anyone offer and suggestions what the source of this noise is?
Thanks in advance....Blake