{"product_id":"heritage-audio-8173-80-series-microphone-preamp-eq-module","title":"Heritage Audio 8173 80 Series Microphone Preamp and EQ Module","description":"\u003ch2\u003eHeritage Audio 8173 80 Series Microphone Preamp and EQ Module\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 8173 Preamp EQ Module 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\/et3BEkLrt4s?si=TocPktDJ0YieXPpX\"\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 8173 80 series microphone preamp EQ module\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_8173_Microphone_Preamplifier_scaled_view.png?v=1771377495\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003eThe 1073 Preamp Meets the 1081 EQ — Finally\u003c\/h2\u003e\n\u003cp\u003eFor decades, engineers working on classic 80 Series consoles faced a choice: the 1073's warm Class A preamp with its limited two-band EQ, or the 1081's far more flexible four-band EQ with its less desirable Class A\/B output stage. Heritage Audio's answer is the 8173 — a module that puts 1073-grade Class A amplification in front of the 1081's full four-band equalizer, a combination that should have existed from the start.\u003c\/p\u003e\n\u003cp\u003eThe 8173 uses Carnhill Transformers' Oxford factory-wound custom input transformers co-designed to Heritage Audio's requirements, ensuring the correct harmonic distortion content and saturation points of original units. Custom polystyrene and polypropylene film tone capacitors were developed to match the Siemens Styroflex and Mullard Mustard types used in late 1960s and early 1970s British consoles. All five PCB cards are handwired in Heritage Audio's factory in Spain using the same old-fashioned soldering techniques of the era.\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 8173 four band EQ 1081 mid bands inductor\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_8173_Microphone_Preamplifier_side_view.png?v=1771377496\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003eFour-Band EQ Covering the Full Audible Spectrum\u003c\/h2\u003e\n\u003cp\u003eThe 8173's EQ section combines 1073-style Baxandall shelving bands for highs and lows with the full 1081 mid band sweep coverage. High-frequency shelving offers ±16 dB at 10, 12, or 16 kHz. Low-frequency shelving offers ±16 dB across four frequencies: 35, 60, 110, or 220 Hz. Both shelf bands use genuine Baxandall curves for that incredibly natural-sounding, musical roll-off and boost that made the original famous.\u003c\/p\u003e\n\u003cp\u003eThe 1081-derived mid bands are inductor-based with fixed Q and cover almost the entire audible frequency range. The upper mid delivers ±18 dB across ten selectable center frequencies from 1.5 kHz to 8.2 kHz — perfect for adding presence, air, or sharpening attack. The lower mid offers ±18 dB across ten frequencies from 220 Hz to 1.2 kHz, covering everything from clearing low-mid mud to shaping body and warmth. An 18 dB\/octave high-pass filter is switchable between 50, 80, and 300 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 8173 Class A ribbon mic 80dB gain impedance\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0646\/4031\/9643\/files\/Heritage_Audio_8173_Microphone_Preamplifier_front_view.png?v=1771377497\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"par-text\"\u003e\n\u003ch2\u003e80dB Class A Preamp With Selectable Input Impedance\u003c\/h2\u003e\n\u003cp\u003eThe 8173's Class A microphone preamp offers up to 80 dB of gain in 5 dB steps with switchable HI\/LO input impedance. In HI mode the minimum impedance is 1,200 Ω, ideal for modern condensers and dynamics. In LO mode the minimum is 300 Ω, optimized for passive ribbon microphones. Higher gain positions gradually increase impedance further, making the 8173 an excellent choice for even the most demanding low-output ribbons.\u003c\/p\u003e\n\u003cp\u003eA 10 dB Class A line amplifier with bridging 10 kΩ input impedance and a 2N3055-driven high-headroom output stage handles line-level sources. Output impedance is less than 75 Ω transformer balanced and floating, capable of driving 600 Ω loads. Maximum output exceeds +26 dBu into 600 Ω and +32 dBu into 10 kΩ. The module is compatible with vintage 80 Series consoles, Heritage Audio Frame 8, and Heritage Audio Rack 2 enclosures. As an authorized dealer, Pro Audio Reserve ensures you receive a genuine Heritage Audio product 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\u003eCombines 1073-style Class A preamp with full 1081-style four-band EQ\u003c\/li\u003e\n\u003cli\u003e80 dB Class A mic preamp in 5 dB steps with HI\/LO selectable input impedance\u003c\/li\u003e\n\u003cli\u003e10 dB Class A line amplifier with 2N3055-driven output stage\u003c\/li\u003e\n\u003cli\u003eHigh-frequency shelving: ±16 dB at 10, 12, or 16 kHz (Baxandall, 1084-style selection)\u003c\/li\u003e\n\u003cli\u003eLow-frequency shelving: ±16 dB at 35, 60, 110, or 220 Hz (Baxandall)\u003c\/li\u003e\n\u003cli\u003eUpper mid EQ: ±18 dB at 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2 kHz (inductor, fixed Q)\u003c\/li\u003e\n\u003cli\u003eLower mid EQ: ±18 dB at 220, 270, 330, 390, 470, 560, 680, 820, 1000, 1200 Hz (inductor, fixed Q)\u003c\/li\u003e\n\u003cli\u003eHigh-pass filter: 18 dB\/octave at 50, 80, or 300 Hz\u003c\/li\u003e\n\u003cli\u003eCustom Carnhill Transformers input transformer (co-designed with Heritage Audio)\u003c\/li\u003e\n\u003cli\u003eCustom vintage-matched tone capacitors (polystyrene and polypropylene film)\u003c\/li\u003e\n\u003cli\u003eMic input impedance: HI = 1,200 Ω min, LO = 300 Ω min\u003c\/li\u003e\n\u003cli\u003eLine input impedance: 10 kΩ bridging\u003c\/li\u003e\n\u003cli\u003eOutput impedance: less than 75 Ω (transformer balanced and floating)\u003c\/li\u003e\n\u003cli\u003eMaximum output: \u0026gt;+26 dBu into 600 Ω, \u0026gt;+32 dBu into 10 kΩ\u003c\/li\u003e\n\u003cli\u003eNoise: less than -100 dBu\u003c\/li\u003e\n\u003cli\u003eTHD: less than 0.025% at 1 kHz, less than 0.05% at 100 Hz\u003c\/li\u003e\n\u003cli\u003eHandwired in Heritage Audio's factory in Spain across five plug-in PCB cards\u003c\/li\u003e\n\u003cli\u003eCompatible with 80 Series consoles, Heritage Audio Frame 8, and Rack 2\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHeritage Audio 8173 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\u003eFormat\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e80 Series module (8¾\" format)\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\u003eCompatible Chassis\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eVintage 80 Series consoles, Heritage Audio Frame 8, Heritage Audio Rack 2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003ePreamp Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eClass A, solid state\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\u003eMaximum Mic Preamp Gain\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eSlightly greater than 80 dB (in 5 dB steps)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eMic Input Impedance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eHI: 1,200 Ω minimum | LO: 300 Ω minimum (transformer balanced and floating)\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\u003eLine Input Impedance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e10 kΩ bridging (transformer balanced and floating)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eDI Input Impedance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eGreater than 2 MΩ (unbalanced)\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\u003eLine Amplifier\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e10 dB Class A, 2N3055-driven high headroom output stage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\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;\"\u003eLess than 75 Ω (transformer balanced and floating)\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\u003eMaximum Output\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u0026gt;+26 dBu into 600 Ω | \u0026gt;+32 dBu into 10 kΩ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\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 (+0.3 dB) to 20 kHz (-0.2 dB)\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\u003eNoise\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eLess than -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;\"\u003eLess than 0.025% at 1 kHz | Less than 0.05% at 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\u003eHigh Frequency EQ\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±16 dB shelving at 10, 12, or 16 kHz (Baxandall)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eLow Frequency EQ\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±16 dB shelving at 35, 60, 110, or 220 Hz (Baxandall)\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\u003eUpper Mid EQ\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±18 dB peaking (fixed Q, inductor) at 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2 kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003eLower Mid EQ\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e±18 dB peaking (fixed Q, inductor) at 220, 270, 330, 390, 470, 560, 680, 820, 1000, 1200 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\u003eHigh-Pass Filter\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e18 dB\/octave at 50, 80, or 300 Hz (inductor based)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e\u003cstrong\u003ePhantom Power\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003e+48V supplied by chassis\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 Consumption\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #ccc;\"\u003eLess than 86 mA per rail @ ±16V DC\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;\"\u003eFive plug-in PCB cards, fully handwired, Carnhill input transformer\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;\"\u003eHeritage Audio 8173 80 Series Microphone Preamp and EQ Module\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":48015793356955,"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_8173_Microphone_Preamplifier_front_view.png?v=1771377497","url":"https:\/\/proaudioreserve.com\/products\/heritage-audio-8173-80-series-microphone-preamp-eq-module","provider":"Pro Audio Reserve","version":"1.0","type":"link"}