The effect of magnetic field was investigated by measuring the resistivity as a function of temperature in different magnetic fields on Bi1.6Pb0.4Sr2Ca3Cu4Oy (2234) samples prepared by solid state reaction, ammonium nitrate and melt quench methods. It was found that the transition temperatures T-c of samples changed with changing magnetic fields. The amount of change was found to be dependent on the sample preparation technique. The samples prepared by solid state reaction and ammonium nitrate methods were affected by magnetic field more than melt quench-annealed samples. Additionally, the critical current density J(c) of samples decreased with increased magnetic field.