Yes, there's adapters available at Radio Shack or Guitar Center. You want a female RCA to Male 1/4 TS plug. Most monitors should be able to "tell" the difference between a balanced and unbalanced signal and compensate for the -6dB drop automatically. Be aware that signals coming out of RCA jacks are sometimes at the "consumer" line level of -10dB instead of the "pro" line level of +4dB.