McIntosh Preamp for McIntosh MC7270

Is Amp OK?

Have you got a CD player you can plug into the amp (turn amp's gain down first, play cd, raise gain, lots of volume?

............................................

Is TT ok?

do you have another unit to temporarily try it? Take TT to a friends house? Take TT to Store (call, prearrange). IOW, is the TT's built-in phono output up to line level?

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

McIntosh amps have a switch on the back, two optional input sensitivities which can change the volume out. Default is 0.75v; verify that,

TURN GAIN (volume) controls way down 1st, then try the other 2.5v setting. Play TT,  Gain up slowly, Big or small difference?

from manual, page 16

https://cdn.shopify.com/s/files/1/0003/3275/9084/files/McIntosh-MC7270-Owners-Manual.pdf?v=1592943508

"INPUT SENSITIVITY Switchable: 0.75 volt or 2.5 volts-level control provided for higher input voltages."

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

How Select Source?

Do you only have a TT plugged into the amp's input jacks, OR, do you have more than 1 source, and if so, how are you selecting which source goes to the amp's input jacks?

How high are you turning your GAIN (volume) controls?

I believe the phone amp in the TT has went cold. Yes it is not playing loud and missing details and bass. The amp is 40 years old with OEM caps and the table is 20+ years old. Both may need a little love. Although I am thinking I need a preamp and wanted thoughts about TT direct to amp?

The link you provided doesn't tell what the output of the phono stage is. It just says the cartridge output is 5mv. 

If that's what going to the amp, it's not nearly enough. I also am using a 7270, it's a great amp that will work great with any preamp.

I have mostly used a C47.