{"product_id":"heritage-audio-motorcity-equalizer-stereo-pair-passive-eq","title":"Heritage Audio MotorCity EQualizer Stereo Pair Seven-Band Passive EQ","description":"\u003ch2\u003eHeritage Audio MotorCity EQualizer Stereo Pair Seven-Band Passive EQ\u003c\/h2\u003e\n\u003c!-- Video Section with Keyword Title --\u003e\n\u003cdiv style=\"margin: 20px auto 10px auto; text-align: center; max-width: 800px;\"\u003e\n\u003ch2 style=\"font-size: 20px; margin-bottom: 12px;\"\u003eHeritage Audio MotorCity EQualizer Overview\u003c\/h2\u003e\n\u003ciframe style=\"width: 100%; max-width: 800px; height: 450px; display: block; margin: 0 auto; border-radius: 8px;\" src=\"https:\/\/www.youtube.com\/embed\/ONFKv5abnuI?si=3jMZgw1xNgfo_gTY\"\u003e\n  \u003c\/iframe\u003e\n\u003c\/div\u003e\n\u003c!-- Section 1 --\u003e\n\u003cdiv class=\"par-section\"\u003e\n\u003cdiv class=\"par-image\"\u003e\u003cimg alt=\"Heritage Audio MotorCity EQualizer stereo pair passive seven-band EQ\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_MOTORCITY_Single-Channel_Passive_EQualizer_front_view.png?v=1771551494\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003eMotown's Secret EQ, Now Public for the First Time\u003c\/h2\u003e\n\u003cp\u003eFor decades, only Michael Brauer had access to these Motown-designed passive EQs — units built privately at Hitsville studio by chief engineer Mike McLean. Heritage Audio reverse-engineered Brauer's personal units (originally based on Cinema Engineering, Langevin, and Altec film industry designs) down to 1% component tolerance. The result: the only publicly available recreation of the \"Holy Grail\" EQ that shaped Motown's sound.\u003c\/p\u003e\n\u003cp\u003eEach unit uses 21 custom-made inductors and 21 custom tone capacitors (three per band) built to match the mil-spec 1960s originals that are no longer manufactured. Heritage Audio worked with Black Lion Audio to measure every component value from Brauer's units, then commissioned new parts with exact materials, values, and tolerances. This isn't an inspired-by clone — it's spec-for-spec identical.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 2 --\u003e\n\u003cdiv class=\"par-section reverse\"\u003e\n\u003cdiv class=\"par-image\"\u003e\u003cimg alt=\"Heritage Audio MotorCity EQ seven bands 50 Hz 12.5 kHz stepped switches\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_MOTORCITY_Single-Channel_Passive_EQualizer_internal_view.png?v=1771551494\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003eSeven Frequency Bands, ±8 dB in 1 dB Steps\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003e50 Hz | 130 Hz | 320 Hz | 800 Hz | 2 kHz | 5 kHz | 12.5 kHz\u003c\/strong\u003e — all stepped switches with ±8 dB range in 1 dB increments. Master gain: ±8 dB in 1 dB steps. Three-way toggle: Off \/ In (bypass) \/ EQ (active). Each frequency uses three inductors and three tone capacitors in a completely passive circuit — no op-amps in the EQ path.\u003c\/p\u003e\n\u003cp\u003eUTC replica input transformer with modified turns ratio for better integration into modern studios (exclusively made for Heritage Audio). Carnhill-driven output line amp replaces the original's unreliable Op-Amp Labs circuit. Input impedance: 2.4 kΩ. Output impedance: 75 Ω. Max output: +26.5 dBu. Noise: -100 dBu. THD: 0.025% @ 1 kHz, 0.05% @ 100 Hz.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 3 --\u003e\n\u003cdiv class=\"par-section\"\u003e\n\u003cdiv class=\"par-image\"\u003e\u003cimg alt=\"Heritage Audio MotorCity EQualizer 10-gauge aluminum Bakelite knobs vintage\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_MOTORCITY_Single-Channel_Passive_EQualizer_rear_view.png?v=1771551494\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003eBuilt Like the Original, Better Where It Counts\u003c\/h2\u003e\n\u003cp\u003e10-gauge hand-brushed aluminum faceplate. Custom-molded Bakelite \"General Radio\" style knobs recreated to match the originals. Jewel-light power indicator. 2U per unit (4U total for stereo pair). External power supply per unit eliminates hum from internal transformers near 21 inductors. Robust XLR connections replace the original's Motown-internal-only jacks.\u003c\/p\u003e\n\u003cp\u003eFrequency response: 20 Hz to 20 kHz (+0.3\/-0.2 dB). Lighter than the original's 30-pound die-cast aluminum tank construction but still substantial due to inductor count. Handmade in Heritage Audio's factory in Spain. As an authorized dealer, Pro Audio Reserve ensures you receive genuine Heritage Audio products backed by full manufacturer warranty and long-term support.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eHighlights\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eStereo pair (two units) — spec-for-spec recreation of Michael Brauer's Motown EQs\u003c\/li\u003e\n\u003cli\u003e21 custom inductors + 21 custom tone capacitors per unit (3 each per band, matched to 1%)\u003c\/li\u003e\n\u003cli\u003eSeven frequency bands: 50, 130, 320, 800 Hz, 2, 5, 12.5 kHz\u003c\/li\u003e\n\u003cli\u003e±8 dB per band in 1 dB stepped increments (heavy-duty rotary switches)\u003c\/li\u003e\n\u003cli\u003eMaster gain: ±8 dB in 1 dB steps\u003c\/li\u003e\n\u003cli\u003eCompletely passive EQ circuit (no op-amps in EQ path)\u003c\/li\u003e\n\u003cli\u003eUTC replica input transformer (modified turns ratio, exclusively made for Heritage)\u003c\/li\u003e\n\u003cli\u003eCarnhill-driven output amp (replaces unreliable original Op-Amp Labs circuit)\u003c\/li\u003e\n\u003cli\u003eThree-way toggle: Off \/ In (bypass) \/ EQ (active)\u003c\/li\u003e\n\u003cli\u003eInput impedance: 2.4 kΩ | Output impedance: 75 Ω\u003c\/li\u003e\n\u003cli\u003eMax output: +26.5 dBu\u003c\/li\u003e\n\u003cli\u003eNoise: -100 dBu | THD: 0.025% @ 1 kHz, 0.05% @ 100 Hz\u003c\/li\u003e\n\u003cli\u003eFrequency response: 20 Hz – 20 kHz (+0.3\/-0.2 dB)\u003c\/li\u003e\n\u003cli\u003e10-gauge hand-brushed aluminum faceplate, custom Bakelite knobs\u003c\/li\u003e\n\u003cli\u003eExternal PSU per unit (90 mA @ 48 VDC)\u003c\/li\u003e\n\u003cli\u003e2U per unit (4U total), handmade in Spain\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHeritage Audio MotorCity EQualizer Specifications\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; border: 1px solid #ccc;\"\u003e\n\u003cthead\u003e\n\u003ctr style=\"background-color: #f2f2f2;\"\u003e\n\u003cth style=\"text-align: left; padding: 10px; border: 1px solid #ccc; width: 35%;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"text-align: left; padding: 10px; border: 1px solid #ccc;\"\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eConfiguration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eStereo pair (two single-channel units)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eEQ Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eCompletely passive (no op-amps in EQ circuit)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eInductors Per Unit\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e21 custom inductors (3 per band)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eTone Capacitors Per Unit\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e21 custom mil-spec tone capacitors (3 per band, matched to 1% tolerance)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eFrequency Bands\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e50 Hz, 130 Hz, 320 Hz, 800 Hz, 2 kHz, 5 kHz, 12.5 kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eBoost\/Cut Range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±8 dB per band (1 dB stepped increments)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eMaster Gain\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±8 dB (1 dB stepped increments)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eBypass\/Engage Switch\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e3-position toggle: Off \/ In (bypass) \/ EQ (active)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eInput Transformer\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eUTC replica (modified turns ratio, exclusively made for Heritage Audio)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eOutput Stage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eCarnhill-driven line amp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eInput Impedance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e2.4 kΩ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eOutput Impedance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e75 Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eMaximum Output Level\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e+26.5 dBu\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eSelf Noise\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e-100 dBu\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eTHD\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e0.025% @ 1 kHz | 0.05% @ 100 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eFrequency Response\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e20 Hz to 20 kHz (+0.3\/-0.2 dB)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eAudio I\/O\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e1 x XLR input, 1 x XLR output (per unit)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003ePower Source\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eExternal PSU with wall-wart transformer (per unit)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003ePower Requirements\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e48 VDC @ 90 mA (per unit)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eRack Spaces\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e2U per unit (4U total for stereo pair)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eDimensions (Per Unit)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e19\" x 4.6\" x 15\" (W x H x D)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eWeight (Per Unit)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e15 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eConstruction\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e10-gauge hand-brushed aluminum faceplate, custom-molded Bakelite knobs, jewel-light indicator\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eManufactured\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eSpain\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eWhat's in the Box\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; border: 1px solid #ccc;\"\u003e\n\u003cthead\u003e\n\u003ctr style=\"background-color: #f2f2f2;\"\u003e\n\u003cth style=\"text-align: left; padding: 10px; border: 1px solid #ccc;\"\u003eIncluded Items\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eTwo Heritage Audio MotorCity EQualizer Single-Channel Passive EQ Units\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eTwo External Power Supplies (48 VDC, 90 mA each)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eTwo Power Cables\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #fafafa;\"\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eUser Documentation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Heritage Audio","offers":[{"title":"Default Title","offer_id":48024187338907,"sku":null,"price":2999.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_MOTORCITY_Single-Channel_Passive_EQualizer_front_view.png?v=1771551494","url":"https:\/\/proaudioreserve.com\/products\/heritage-audio-motorcity-equalizer-stereo-pair-passive-eq","provider":"Pro Audio Reserve","version":"1.0","type":"link"}