In addition to the response by Mofimadness, the GTP-500 has separate recording and listening selectors. If you use the preamp output, set the listening selector to phono, and if using the tape output, set the recording selector to phono.
Can I connect 2 Adcom Preamps?
I am new to this and I have the following system, Adcom GTP-600 preamp, Adcom GFA-5500 and Adcom GFA-6000 amps. I have been running my phono through a Recoton converter. Recently I acquired an Adcom GTP-500 preamp which has phono inputs, but not enough space for everything I have. Is it possible to just add this preamp to the setup I already have?