What is the purpose of preamp jumpers?


I have a Marantz receiver vintage 1974 and I was wondering if anyone can tell me the purpose of a set of preamp jumpers supplied with the unit?
walnut

Showing 1 response by jetter

Is there any issue with using the receiver amp with another preamp. I have an old yamaha receiver with the same jumper set up and was wondering if I could try the amp section of the receiver with my tube preamp?