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Heritage Audio 6673 80 Series Microphone Preamp and EQ Module

$2,999.00
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Description



Heritage Audio 6673 Preamp EQ Module Overview

  Heritage Audio 6673 80 series microphone preamp four-band EQ module

1073 Preamp + 1066 Constant-Q Mid = Four-Band EQ Monster

The 6673 solves a 50-year-old problem: choosing between the 1073's punchy three-band EQ and the 1066's sweet constant-Q midband. Heritage Audio put both in one module. You get the 1073's full three-band circuit plus the 1066's inductor-based constant-Q mid EQ — four bands total. The 1073 mid section was expanded with three additional frequencies (240, 360, 530 Hz) for better low-mid control. High shelf now switches between 10, 12, or 16 kHz instead of being fixed at 12 kHz.

Same Class A 73-style preamp as the 8173: 80 dB gain in 5 dB steps, HI/LO impedance switch (1,200 Ω / 300 Ω minimum), Carnhill transformers, 2N3055-driven output stage. Noise below -100 dBu, THD under 0.025% at 1 kHz. Handwired in Spain on five plug-in PCB cards using 1970s soldering techniques.

 Heritage Audio 6673 four band EQ 1073 1066 inductor constant Q

Four Inductor-Based EQ Bands Cover 35 Hz to 16 kHz

High shelf (Baxandall): ±16 dB at 10, 12, or 16 kHz
Low shelf (Baxandall): ±16 dB at 35, 60, 110, or 220 Hz
1073 mid (fixed Q, dual inductor): ±18 dB at 240, 360, 530, 700, 1100, 1600, 3200, 4800, 7200, 10000 Hz
1066 mid (constant Q, inductor): ±18 dB at 700, 1200, 2400, 3600, 7000 Hz
High-pass filter: 18 dB/octave at 50, 80, or 300 Hz

Both mid bands can be used simultaneously — boost at 700 Hz with the 1066 circuit for thick guitars, then cut at 360 Hz with the 1073 band to clear mud. The constant-Q 1066 circuit maintains consistent bandwidth regardless of boost/cut amount, unlike the 1073's fixed-Q design.

 Heritage Audio 6673 Class A ribbon mic 80dB gain impedance

80 Series Compatible, Frame 8, or Rack 2 Ready

Fits vintage 80 Series consoles, Heritage Audio Frame 8, and Rack 2 enclosures. 10 dB Class A line amplifier with 10 kΩ bridging input impedance. Output impedance below 75 Ω transformer-balanced and floating, drives 600 Ω loads. Maximum output greater than +26 dBu into 600 Ω and greater than +32 dBu into 10 kΩ. Frequency response 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB).

Power consumption under 110 mA at 24V DC (supplied by chassis). As an authorized dealer, Pro Audio Reserve ensures you receive a genuine Heritage Audio product backed by full manufacturer warranty and long-term support.

Highlights

  • 1073 Class A preamp + 1066 constant-Q mid EQ + expanded 1073 mid = 4-band module
  • 80 dB Class A mic preamp (5 dB steps), 10 dB Class A line amp
  • HI/LO mic impedance: 1,200 Ω / 300 Ω minimum (ribbon compatible)
  • Carnhill input/output transformers, 2N3055 output stage
  • High shelf (Baxandall): ±16 dB at 10, 12, 16 kHz
  • Low shelf (Baxandall): ±16 dB at 35, 60, 110, 220 Hz
  • 1073 mid (dual inductor, fixed Q): ±18 dB at 10 frequencies (240–10k Hz)
  • 1066 mid (inductor, constant Q): ±18 dB at 700, 1200, 2400, 3600, 7000 Hz
  • 18 dB/oct high-pass: 50, 80, 300 Hz (inductor)
  • Max output: >+26 dBu (600 Ω), >+32 dBu (10 kΩ)
  • Noise: <-100 dBu | THD: <0.025% (1 kHz), <0.05% (100 Hz)
  • Frequency response: 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB)
  • Handwired in Spain on five PCB cards
  • Compatible: 80 Series consoles, Frame 8, Rack 2

Heritage Audio 6673 Specifications

Specification Details
Format 80 Series module (1073-sized)
Compatible Chassis Vintage 80 Series consoles, Heritage Audio Frame 8, Heritage Audio Rack 2
Preamp Type Class A, solid state (73-style)
Maximum Mic Preamp Gain Slightly greater than 80 dB (in 5 dB steps)
Mic Input Impedance HI: 1,200 Ω minimum | LO: 300 Ω minimum (transformer balanced and floating)
Line Input Impedance 10 kΩ bridging (transformer balanced and floating)
Line Amplifier 10 dB Class A, 2N3055-driven high headroom output stage
Output Impedance Less than 75 Ω (transformer balanced and floating)
Maximum Output >+26 dBu into 600 Ω | >+32 dBu into 10 kΩ
Frequency Response 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB)
Noise Less than -100 dBu
THD Less than 0.025% at 1 kHz | Less than 0.05% at 100 Hz
High Frequency EQ ±16 dB shelving at 10, 12, or 16 kHz (Baxandall)
Low Frequency EQ ±16 dB shelving at 35, 60, 110, or 220 Hz (Baxandall)
1073 Mid EQ ±18 dB peaking (fixed Q, dual inductor) at 240, 360, 530, 700, 1100, 1600, 3200, 4800, 7200, 10000 Hz
1066 Mid EQ ±18 dB peaking (constant Q, inductor) at 700, 1200, 2400, 3600, 7000 Hz
High-Pass Filter 18 dB/octave at 50, 80, or 300 Hz (inductor based)
Phantom Power +48V supplied by chassis
Power Consumption Less than 110 mA @ 24V DC
Construction Five plug-in PCB cards, fully handwired, Carnhill transformers
Manufactured Spain

What's in the Box

Included Items
Heritage Audio 6673 80 Series Microphone Preamp and EQ Module
User Documentation
Shipping

Shipping & Returns

  • We deliver all US orders in 3–5 business days
  • Free cancellations
  • Returns accepted within 30 days (unused items)

Order Confirmation

Once your order is placed, you will receive an order confirmation email. This confirms that we have received your order and have pre-authorized your credit card for the purchase. After confirming availability with our suppliers, we will proceed accordingly:

  • If your item is available and ready to ship within 1–2 business days, we will process the charge and arrange for shipment.

  • If your item is on backorder or unavailable, the pre-authorization will be voided and you will be notified by email.

  • Please note: While most items ship out within 1–2 business days, total delivery time is typically 3–5 business days, depending on your location and carrier handling.

Order Shipment

If your item is in stock and your payment has been processed, your order will typically ship within 1–2 business days. Total delivery time is approximately 3–5 business days from the date of order. Once shipped, you will receive tracking information at the email address provided during checkout within 24 hours of dispatch.

If you have not received tracking information within 3–5 business days of placing your order, please contact us at support@proaudioreserve.com.

The Distributor-Direct Advantage

To ensure you receive the most recent hardware revisions and 100% factory-sealed units, Pro Audio Reserve utilizes a Distributor-Direct fulfillment model. Unlike big-box retailers that may ship "floor models" or gear that has been sitting in general-purpose warehouses, your equipment is pulled directly from the primary manufacturer hub, serialized, and dispatched. This process ensures the highest level of quality control for professional-grade recording equipment.

Shipping Policy

We currently offer free shipping within the United States only. If the checkout process on our website allows you to enter a shipping address and complete your order, your location is eligible to receive delivery.

Changing Shipping Address

If you need to change your shipping address after your order has been processed or shipped, we will do our best to accommodate the request. Please note that address changes may result in delivery delays. Any additional costs incurred due to address changes, including carrier fees or rerouting charges will be the responsibility of the customer. No exceptions.

Shipping Times

All shipping times provided are estimates and should not be considered guarantees. Most orders ship out within 1–2 business days from the time payment is processed. However, total delivery time is typically 3–5 business days, depending on your location, carrier performance, and supplier fulfillment timelines.

We work closely with our vendors to ensure timely deliveries, but please note that supply chain disruptions, high-demand periods, or weather events may occasionally cause delays beyond our control.

  • To avoid misunderstandings: The “shipping time” refers to the total time from order placement to final delivery, not just when the item leaves the warehouse.

  • Cancellations: If you choose to cancel your order because it has not arrived within the estimated delivery window, you may be responsible for applicable shipping charges, restocking fees, warehouse handling costs, and other related fees.

  • Chargebacks: Customers who initiate chargebacks due to shipping delays without contacting us first may be held legally responsible for losses. We strongly encourage open communication so we can resolve any delivery concerns directly and efficiently via our Atlanta-based support team.

Delivery Options

  • Threshold Shipping: Your item will be delivered to your front door, porch, garage, or a covered entryway.

 

Why Buy From Us

We get it. You've got a lot of choice when it comes to online retailers.
Here's why we think you should shop with us at ProAudioReserve.

  • Free Shipping USA wide. 
  • 30 Day Easy Returns. Not happy with your product, we'll take it back noquestions asked.
  • Great Service. We pride ourselves on the best service, anywhere.

Reviews

Customer Reviews

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Description



Heritage Audio 6673 Preamp EQ Module Overview

  Heritage Audio 6673 80 series microphone preamp four-band EQ module

1073 Preamp + 1066 Constant-Q Mid = Four-Band EQ Monster

The 6673 solves a 50-year-old problem: choosing between the 1073's punchy three-band EQ and the 1066's sweet constant-Q midband. Heritage Audio put both in one module. You get the 1073's full three-band circuit plus the 1066's inductor-based constant-Q mid EQ — four bands total. The 1073 mid section was expanded with three additional frequencies (240, 360, 530 Hz) for better low-mid control. High shelf now switches between 10, 12, or 16 kHz instead of being fixed at 12 kHz.

Same Class A 73-style preamp as the 8173: 80 dB gain in 5 dB steps, HI/LO impedance switch (1,200 Ω / 300 Ω minimum), Carnhill transformers, 2N3055-driven output stage. Noise below -100 dBu, THD under 0.025% at 1 kHz. Handwired in Spain on five plug-in PCB cards using 1970s soldering techniques.

 Heritage Audio 6673 four band EQ 1073 1066 inductor constant Q

Four Inductor-Based EQ Bands Cover 35 Hz to 16 kHz

High shelf (Baxandall): ±16 dB at 10, 12, or 16 kHz
Low shelf (Baxandall): ±16 dB at 35, 60, 110, or 220 Hz
1073 mid (fixed Q, dual inductor): ±18 dB at 240, 360, 530, 700, 1100, 1600, 3200, 4800, 7200, 10000 Hz
1066 mid (constant Q, inductor): ±18 dB at 700, 1200, 2400, 3600, 7000 Hz
High-pass filter: 18 dB/octave at 50, 80, or 300 Hz

Both mid bands can be used simultaneously — boost at 700 Hz with the 1066 circuit for thick guitars, then cut at 360 Hz with the 1073 band to clear mud. The constant-Q 1066 circuit maintains consistent bandwidth regardless of boost/cut amount, unlike the 1073's fixed-Q design.

 Heritage Audio 6673 Class A ribbon mic 80dB gain impedance

80 Series Compatible, Frame 8, or Rack 2 Ready

Fits vintage 80 Series consoles, Heritage Audio Frame 8, and Rack 2 enclosures. 10 dB Class A line amplifier with 10 kΩ bridging input impedance. Output impedance below 75 Ω transformer-balanced and floating, drives 600 Ω loads. Maximum output greater than +26 dBu into 600 Ω and greater than +32 dBu into 10 kΩ. Frequency response 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB).

Power consumption under 110 mA at 24V DC (supplied by chassis). As an authorized dealer, Pro Audio Reserve ensures you receive a genuine Heritage Audio product backed by full manufacturer warranty and long-term support.

Highlights

  • 1073 Class A preamp + 1066 constant-Q mid EQ + expanded 1073 mid = 4-band module
  • 80 dB Class A mic preamp (5 dB steps), 10 dB Class A line amp
  • HI/LO mic impedance: 1,200 Ω / 300 Ω minimum (ribbon compatible)
  • Carnhill input/output transformers, 2N3055 output stage
  • High shelf (Baxandall): ±16 dB at 10, 12, 16 kHz
  • Low shelf (Baxandall): ±16 dB at 35, 60, 110, 220 Hz
  • 1073 mid (dual inductor, fixed Q): ±18 dB at 10 frequencies (240–10k Hz)
  • 1066 mid (inductor, constant Q): ±18 dB at 700, 1200, 2400, 3600, 7000 Hz
  • 18 dB/oct high-pass: 50, 80, 300 Hz (inductor)
  • Max output: >+26 dBu (600 Ω), >+32 dBu (10 kΩ)
  • Noise: <-100 dBu | THD: <0.025% (1 kHz), <0.05% (100 Hz)
  • Frequency response: 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB)
  • Handwired in Spain on five PCB cards
  • Compatible: 80 Series consoles, Frame 8, Rack 2

Heritage Audio 6673 Specifications

Specification Details
Format 80 Series module (1073-sized)
Compatible Chassis Vintage 80 Series consoles, Heritage Audio Frame 8, Heritage Audio Rack 2
Preamp Type Class A, solid state (73-style)
Maximum Mic Preamp Gain Slightly greater than 80 dB (in 5 dB steps)
Mic Input Impedance HI: 1,200 Ω minimum | LO: 300 Ω minimum (transformer balanced and floating)
Line Input Impedance 10 kΩ bridging (transformer balanced and floating)
Line Amplifier 10 dB Class A, 2N3055-driven high headroom output stage
Output Impedance Less than 75 Ω (transformer balanced and floating)
Maximum Output >+26 dBu into 600 Ω | >+32 dBu into 10 kΩ
Frequency Response 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB)
Noise Less than -100 dBu
THD Less than 0.025% at 1 kHz | Less than 0.05% at 100 Hz
High Frequency EQ ±16 dB shelving at 10, 12, or 16 kHz (Baxandall)
Low Frequency EQ ±16 dB shelving at 35, 60, 110, or 220 Hz (Baxandall)
1073 Mid EQ ±18 dB peaking (fixed Q, dual inductor) at 240, 360, 530, 700, 1100, 1600, 3200, 4800, 7200, 10000 Hz
1066 Mid EQ ±18 dB peaking (constant Q, inductor) at 700, 1200, 2400, 3600, 7000 Hz
High-Pass Filter 18 dB/octave at 50, 80, or 300 Hz (inductor based)
Phantom Power +48V supplied by chassis
Power Consumption Less than 110 mA @ 24V DC
Construction Five plug-in PCB cards, fully handwired, Carnhill transformers
Manufactured Spain

What's in the Box

Included Items
Heritage Audio 6673 80 Series Microphone Preamp and EQ Module
User Documentation
Shipping

Shipping & Returns

  • We deliver all US orders in 3–5 business days
  • Free cancellations
  • Returns accepted within 30 days (unused items)

Order Confirmation

Once your order is placed, you will receive an order confirmation email. This confirms that we have received your order and have pre-authorized your credit card for the purchase. After confirming availability with our suppliers, we will proceed accordingly:

  • If your item is available and ready to ship within 1–2 business days, we will process the charge and arrange for shipment.

  • If your item is on backorder or unavailable, the pre-authorization will be voided and you will be notified by email.

  • Please note: While most items ship out within 1–2 business days, total delivery time is typically 3–5 business days, depending on your location and carrier handling.

Order Shipment

If your item is in stock and your payment has been processed, your order will typically ship within 1–2 business days. Total delivery time is approximately 3–5 business days from the date of order. Once shipped, you will receive tracking information at the email address provided during checkout within 24 hours of dispatch.

If you have not received tracking information within 3–5 business days of placing your order, please contact us at support@proaudioreserve.com.

The Distributor-Direct Advantage

To ensure you receive the most recent hardware revisions and 100% factory-sealed units, Pro Audio Reserve utilizes a Distributor-Direct fulfillment model. Unlike big-box retailers that may ship "floor models" or gear that has been sitting in general-purpose warehouses, your equipment is pulled directly from the primary manufacturer hub, serialized, and dispatched. This process ensures the highest level of quality control for professional-grade recording equipment.

Shipping Policy

We currently offer free shipping within the United States only. If the checkout process on our website allows you to enter a shipping address and complete your order, your location is eligible to receive delivery.

Changing Shipping Address

If you need to change your shipping address after your order has been processed or shipped, we will do our best to accommodate the request. Please note that address changes may result in delivery delays. Any additional costs incurred due to address changes, including carrier fees or rerouting charges will be the responsibility of the customer. No exceptions.

Shipping Times

All shipping times provided are estimates and should not be considered guarantees. Most orders ship out within 1–2 business days from the time payment is processed. However, total delivery time is typically 3–5 business days, depending on your location, carrier performance, and supplier fulfillment timelines.

We work closely with our vendors to ensure timely deliveries, but please note that supply chain disruptions, high-demand periods, or weather events may occasionally cause delays beyond our control.

  • To avoid misunderstandings: The “shipping time” refers to the total time from order placement to final delivery, not just when the item leaves the warehouse.

  • Cancellations: If you choose to cancel your order because it has not arrived within the estimated delivery window, you may be responsible for applicable shipping charges, restocking fees, warehouse handling costs, and other related fees.

  • Chargebacks: Customers who initiate chargebacks due to shipping delays without contacting us first may be held legally responsible for losses. We strongly encourage open communication so we can resolve any delivery concerns directly and efficiently via our Atlanta-based support team.

Delivery Options

  • Threshold Shipping: Your item will be delivered to your front door, porch, garage, or a covered entryway.

 

Why Buy From Us

We get it. You've got a lot of choice when it comes to online retailers.
Here's why we think you should shop with us at ProAudioReserve.

  • Free Shipping USA wide. 
  • 30 Day Easy Returns. Not happy with your product, we'll take it back noquestions asked.
  • Great Service. We pride ourselves on the best service, anywhere.

Reviews

Customer Reviews

Be the first to write a review
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(0)
0%
(0)
0%
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