If you mic the instruments close, they should sound close, doesn't really matter the quality of the gear. Sounds like maybe another issue?
A few tricks. If you are using reverb, tone it down or cut it out. If we're talking guitars here, boosting EQ in the high mids will bring it forward (experiment with 2-4k here, it really varies though). Did you record them with the mic in the center of the speaker cone, or toward the edge?
While I was writing this, I was also thinking too....do you want it to sound close, or thick? They're not mutual exclusive, but they are two different things to achieve. I tend to get thicker sounding guitars a little further back from the amp....its not as 'close' sounding, but it does sound bigger.