How the Model 10B Differs from the Model 10
The Model 10b uses gapped pot cores cores for the IF stage inductors. Marantz found that the the toroid cores used in the model 10 were becoming magnetized on the production line due to the use of Weller soldering equipment (these use a temperature-sensitive magnetic tip to control the applied heat energy.)
When the magnitization occurred, the tuners could not be aligned, and this required a costly re-work of the model 10 tuner prior to shipment, hencce the change for the 10B production run.
The dial mechanism was also redesigned from the model 10 for the 10B production run.
In the 10B, the IF stages were aligned in an oven. Marantz engineering knew that the chassis would run at a certain temperature, so they designed a setup which would keep the IF strip at the correct temperature for alignment, thus ensuring that once the tuner reached its normal operating temperature, it would be completely "peaked".
Contributed by Ben Blish
On March 1st, 2000