You are quite likely to bet a number of negative responses to your question. This is a group that is very passionate about this breed, and many of our members work in Rescue and see the results of indiscriminate breeders everyday.
Please stay around and learn and to all my fellow DTers... be kind, I believe this OP has asked a sincere, uninformed question. Let's educate rather than persecute!
As to your question -- please, don't do it! The best way to go about getting another Dobe is to purchase one, or better yet adopt one from a rescue. There are thousands and thousands of Dobes in rescues and shelters waiting for a home. Please do not add to over-population problem.
Is there any reason you can't go back to the breeder you got your current boy from and get another? If that's not possible, then post his pedigree and we may just be able to direct you to a breeder that breeds the same basic lines.
The Dobe gene pool is pretty small and they are all pretty much related one way or another. I have 2 now, a male born in 2008 and a female born earlier this year and they are both from the same basic lines as my very first Doberman, that I got in 1968!
Please don't breed. Neuter your male, love and enjoy him and if you are looking into getting another, please make sure you educate yourself on the many health issues Dobes have as well as same sex aggression. You will definitely want a female.
Welcome to DT and brace yourself for the onslaught.
AKC GCH/UKC CH, RO3 Lyndobe's Wheel of Fortune, "Wheeler"
AKC UKC CH Windsong's Fortune Hunter v Shelian, "Spock"
AKC UKC CH Windsong's Fame N Fortune v Shelian, "Fame"