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Whitestone Audio P331 EVL front view

Whitestone Audio P331 EVL Tube Loading Amplifier

$5,999.00

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Description

Whitestone Audio P331 EVL Tube Loading Amplifier

 

Whitestone Audio P331 EVL Demo

  Whitestone Audio P331 EVL tube loading amplifier

6SN7 Vacuum Tubes and High-Voltage Linear Power Supply

The soul of the P331 EVL is its 6SN7 8-pin double-triode vacuum tubes, which inject nuanced harmonic excitement into a signal without adding obvious distortion. These carefully selected tubes create the subtle even-order harmonics and refined nonlinearities that give the P331 EVL its character and musicality.

The heart of the P331 EVL is its high-voltage linear power supply that ensures the utmost in audio integrity — a must-have for mission-critical applications such as mastering. The brain of this unit is its digitally controlled analog design, which allows for unparalleled precision with absolute repeatability. Every parameter can be fully recalled, making the P331 EVL perfect for modern workflows that demand consistency across sessions.

 Whitestone Audio P331 EVL Bloom mode Lift circuit transformers

Dual-Mode Loading Circuit and Lift Parallel Filter

The P331 EVL's loading circuit includes a Clean (feedback) mode and a plate-loaded Bloom (feedforward) mode for adding nonlinearities and even-order harmonics to your audio. The EVL's tube-loading amplifier pushes harder right from the start compared to the original P331, causing it to sound more aggressive and punch through mixes with additional authority.

The Lift circuit is a gentle parallel filter that selectively enhances specific frequency ranges within your audio signal. Since the Lift circuit affects harmonics generated by the tube-loading amplifier, it behaves differently on the EVL compared to the original model, offering unique tonal possibilities. The Auto-Padding feature (Pre, Post, and Open modes) pads down your signal inversely as gain increases through the tubes, maintaining optimal levels throughout the circuit.

 Whitestone Audio P331 EVL output amplifier bypass switching

Switchable Output Transformers and Balanced Output Amp

The Xformer section includes switchable output transformers, enabling you to toggle between a clean, transformerless signal path and two options with transformers engaged. Since the EVL pushes more current through its output transformers than the original P331, you can expect more saturation, thrust, and punch — the EVL simply sounds meaner.

A low-distortion, fully balanced solid-state output amplifier provides up to 11 dB of boost or cut in 1 dB increments, with a Resolution mode for even finer control. Each section of the P331 EVL includes individual hard-wire bypass, plus there's a global hard-wire bypass for removing the entire unit from your signal chain. This mastering-grade tool ensures you can add that elusive analog magic to productions while maintaining complete control over your sonic palette.

Highlights

  • Mastering-grade tube loading amplifier for subtle harmonic coloration
  • 6SN7 8-pin double-triode vacuum tubes for nuanced harmonic excitement
  • High-voltage linear power supply for maximum audio integrity
  • Digitally controlled analog design with absolute repeatability and recall
  • EVL design pushes harder from the start for more aggressive sound
  • Dual-mode loading circuit: Clean (feedback) and Bloom (feedforward)
  • Auto-Padding feature with Pre, Post, and Open modes
  • Lift circuit: gentle parallel filter for selective frequency enhancement
  • Xformer section with switchable output transformers
  • EVL pushes more current through transformers for additional saturation and punch
  • Low-distortion, fully balanced solid-state output amplifier
  • 11 dB of boost or cut in 1 dB increments with Resolution mode
  • Individual hard-wire bypass per section plus global bypass
  • Two-channel stereo operation
  • Perfect for tracking, mixing, and mastering applications

Whitestone Audio P331 EVL Specifications

Specification Details
Processor Type Tube-loading amplifier
Number of Channels 2 (stereo)
Vacuum Tubes 6SN7 8-pin double-triode
Power Supply High-voltage linear power supply
Control Design Digitally controlled analog with full repeatability and recall
Loading Circuit Modes Clean (feedback), Bloom (feedforward plate-loaded)
Auto-Padding Modes Pre, Post, Open
Lift Circuit Gentle parallel filter for selective frequency enhancement
Xformer Section Switchable output transformers (clean/transformerless or two transformer-engaged options)
Output Amplifier Low-distortion, fully balanced solid-state
Output Gain Range ±11 dB in 1 dB increments with Resolution mode for finer control
Bypass Individual hard-wire bypass per section, global hard-wire bypass
Analog Inputs 2 x XLR (balanced)
Analog Outputs 2 x XLR (balanced)
Power Source Standard IEC AC cable
Model Variant EVL (black) - more aggressive than original P331 (white)

What's in the Box

Included Items
Whitestone Audio P331 EVL Tube Loading Amplifier
Power Cable
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

Whitestone Audio P331 EVL Tube Loading Amplifier

 

Whitestone Audio P331 EVL Demo

  Whitestone Audio P331 EVL tube loading amplifier

6SN7 Vacuum Tubes and High-Voltage Linear Power Supply

The soul of the P331 EVL is its 6SN7 8-pin double-triode vacuum tubes, which inject nuanced harmonic excitement into a signal without adding obvious distortion. These carefully selected tubes create the subtle even-order harmonics and refined nonlinearities that give the P331 EVL its character and musicality.

The heart of the P331 EVL is its high-voltage linear power supply that ensures the utmost in audio integrity — a must-have for mission-critical applications such as mastering. The brain of this unit is its digitally controlled analog design, which allows for unparalleled precision with absolute repeatability. Every parameter can be fully recalled, making the P331 EVL perfect for modern workflows that demand consistency across sessions.

 Whitestone Audio P331 EVL Bloom mode Lift circuit transformers

Dual-Mode Loading Circuit and Lift Parallel Filter

The P331 EVL's loading circuit includes a Clean (feedback) mode and a plate-loaded Bloom (feedforward) mode for adding nonlinearities and even-order harmonics to your audio. The EVL's tube-loading amplifier pushes harder right from the start compared to the original P331, causing it to sound more aggressive and punch through mixes with additional authority.

The Lift circuit is a gentle parallel filter that selectively enhances specific frequency ranges within your audio signal. Since the Lift circuit affects harmonics generated by the tube-loading amplifier, it behaves differently on the EVL compared to the original model, offering unique tonal possibilities. The Auto-Padding feature (Pre, Post, and Open modes) pads down your signal inversely as gain increases through the tubes, maintaining optimal levels throughout the circuit.

 Whitestone Audio P331 EVL output amplifier bypass switching

Switchable Output Transformers and Balanced Output Amp

The Xformer section includes switchable output transformers, enabling you to toggle between a clean, transformerless signal path and two options with transformers engaged. Since the EVL pushes more current through its output transformers than the original P331, you can expect more saturation, thrust, and punch — the EVL simply sounds meaner.

A low-distortion, fully balanced solid-state output amplifier provides up to 11 dB of boost or cut in 1 dB increments, with a Resolution mode for even finer control. Each section of the P331 EVL includes individual hard-wire bypass, plus there's a global hard-wire bypass for removing the entire unit from your signal chain. This mastering-grade tool ensures you can add that elusive analog magic to productions while maintaining complete control over your sonic palette.

Highlights

  • Mastering-grade tube loading amplifier for subtle harmonic coloration
  • 6SN7 8-pin double-triode vacuum tubes for nuanced harmonic excitement
  • High-voltage linear power supply for maximum audio integrity
  • Digitally controlled analog design with absolute repeatability and recall
  • EVL design pushes harder from the start for more aggressive sound
  • Dual-mode loading circuit: Clean (feedback) and Bloom (feedforward)
  • Auto-Padding feature with Pre, Post, and Open modes
  • Lift circuit: gentle parallel filter for selective frequency enhancement
  • Xformer section with switchable output transformers
  • EVL pushes more current through transformers for additional saturation and punch
  • Low-distortion, fully balanced solid-state output amplifier
  • 11 dB of boost or cut in 1 dB increments with Resolution mode
  • Individual hard-wire bypass per section plus global bypass
  • Two-channel stereo operation
  • Perfect for tracking, mixing, and mastering applications

Whitestone Audio P331 EVL Specifications

Specification Details
Processor Type Tube-loading amplifier
Number of Channels 2 (stereo)
Vacuum Tubes 6SN7 8-pin double-triode
Power Supply High-voltage linear power supply
Control Design Digitally controlled analog with full repeatability and recall
Loading Circuit Modes Clean (feedback), Bloom (feedforward plate-loaded)
Auto-Padding Modes Pre, Post, Open
Lift Circuit Gentle parallel filter for selective frequency enhancement
Xformer Section Switchable output transformers (clean/transformerless or two transformer-engaged options)
Output Amplifier Low-distortion, fully balanced solid-state
Output Gain Range ±11 dB in 1 dB increments with Resolution mode for finer control
Bypass Individual hard-wire bypass per section, global hard-wire bypass
Analog Inputs 2 x XLR (balanced)
Analog Outputs 2 x XLR (balanced)
Power Source Standard IEC AC cable
Model Variant EVL (black) - more aggressive than original P331 (white)

What's in the Box

Included Items
Whitestone Audio P331 EVL Tube Loading Amplifier
Power Cable
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
0%
(0)
0%
(0)
0%
(0)
0%
(0)
0%
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