6 and 10 bands for UREI 546 parametric equalizer

It is true, I cannot found really correct math expression to modify the band-frequency of UREI 546 EQ circuit, but I think I have a very useful Excel sheet. I think the not 100% exact expression is not a big problem, because the frequency parameter is adjustable. I have a plan UREI 546 with 6 bands, but I counted out values of potentiometers and capacitors for 10 bands. For 10 bands EQ I will design mainboard later.

The first table for original 4 bands, 6 bands, and 10 bands:


The result is the value of P1 stereo potentiometers for frequency adjustment, and the capacitor of filter C(a) = C(b). If somebody have better expression please send me a message.

Another table just for variations:

See also:

• Simulation of UREI LP/HP filter module
• Modular, expandable parametric equalizer based on UREI546
• Simulation of 8 band parametric equalizer
• Simulation and software analysis of UREI 546
• UREI546 parametric EQ like URS VST EQ bundle
• Math expression for UREI546 parametric EQ design
• Parametric EQ Project - Modular UREI545 and 546
• Modular equalizer with gyrator filter
• PDF manual of modular gyrator EQ
• PDF manual of UREI 545 and 546 EQ clone

PCB sales of this project Module name Size (mm) Area (cm2) PDF SCH PCB image Tested Price (US$) Des./3D Sim.1 Full2 Sim.1 Full2 Man3 Parametric EQ module 56x61 34 Yes Yes Yes - - - 7 14 Yes 2 Potmeter module 31x62 19 Yes Yes Yes - - - 5 12 Yes 3 Potmeter module 41x83 34 Yes Yes Yes - - - 6 14 Yes Power filter module V:1 51x22 11 Yes Yes Yes - - - 3 11 Yes UREI545 clone mainboard V:2 217x143 310 Yes Yes Yes - - - 43 53 Yes UREI545 clone mainboard V:1 217x198 430 Yes Yes Yes - - - 59 70 Yes 6 band UREI546 mainboard 173x143 247 Yes Yes Yes - - - 35 44 Yes Power supply 121x57 69 Yes Yes Yes - - - 11 20 Yes How to order? Please read the rules carefully!