Trying to mate Magnecord's top of the line (and most expensive) professional M90 tape transport with their cheapest consumer "magnecordette" electronics is not a good idea. Even if it could be done with extensive modifications and research work the results will be less than optimal. There are really too much differences between the M90 and Magnecordette electronics. Separate M90 preamps appears from time to time on the well know auction site. Try to get one , it really worth the expense as the M90 was Magnecord's best recorder, similar to (if not better) an AMPEX 351.