251 to 122

[Esteban Lorenzo Chavez <echavez@flute.aix.calpoly.edu>]

Hello Folks,

I just purchased a C3 with a 21H for a measly $750. Ok...whats wrong with 
it? Well the percusion is a little tweaked, the amp is not loud 
enough, and the leslie switch does not work,but other than than it is in 
great condition. 

I just got a line on a leslie model 251. It is my understanding that the 
251 is the same as the the 122 except for the additional channel and the 
fact that it is unbalanced compared to the 122's balanced input.

Is there a great tonal difference between the two? Is the 251 a two speed? 
Can the 251 be wired to work with the C3? Would it be worth my time and $?
Also is it possible to convert a six pin leslie cable to a five pin
male/six pin female? 

I apologize if these are silly questions, but thanks in advance for any 
advice.

Chavez