I read somewhere that I'll need something between my solid state radio and the tube amp I'm building.I didn't see any coments about output power of radio.Allot of the SS amps I looked at needed a low Input
Typically, a tube amp would have the following connections between the XCVR and the AMP in addition to the COAX connection (XCVR Antenna out to AMP RF Input).
(1) Keying relay interface. This is where you might use a relay buffer like the ARB-704 (See Ameritron web site). This is to protect the relay in your XCVR from over voltage damage caused by the amp. Not all XCVR/AMP interfaces need one. If you know that your amp cannot cause damage to your XCVR keying relay then you may get by without one.
(2) ALC control line. This is used with a tube amplifier to protect grid current (usually) in the amplifier from being too high by overdriving from the XCVR. Depending on how you operate this may be important (but, your amplifier will work without it too).
Caveat -- I am not near as experienced or knowledgeable as other's on this forum with regard to ALC and other practices with tube amps so take my comments above with a grain of salt. If someone like Tom, W8JI, or Steve, WB2WIK, comment then their comments will always trump mine with regard to amps.
73, phil, K7PEH