VU meter connection

Hi there apologies if this has been discussed but I am building a VU peak meter with a VU kit which includes a driver and 2 VUs. Works great but not sure best way to get signal to meters. Atm ive got input from tape rec rca out on amp but the signal is low. What is the best way to connect to get the VU levels to correspond with volume control? Thanks
 
Yeh the headphone out works a treat. Thanks. I created a mockup with foam board facia and it works well. Getting new acrylic facia laser cut and then will complete project adding labels, tidying up wiring and might add preamp and potentiometers for gains.