Documents

CASE STUDY: Developing a Multi-Channel DAC for High-End Audio Applications

Tomhazan1 — Thu, 11 Sep 2025 06:17:31 GMT

Current Revision posted to Documents by Tomhazan1 on 9/11/2025 6:17:31 AM

CASE STUDY: Developing a Multi-Developing Multi-Channel DAC for High-End Audio | VPG Foil Resistors

Author: Vincent Brient, Inventor Chief Engineer, TOTALDAC

Industry/ Application Area

High-End Audio

Product Used

VSR series Bulk Metal^® Foil resistors

Description of Case Study

To build the best-sounding audio multi-channel digital-to-analog converter (DAC), we tested DAC ICs from various suppliers before settling on a solution using an FPGA and 96 VSR series resistors per channel in a 3-channel configuration.

The Challenge

Our goal was to create a no-compromises DAC and digital crossover with 69-bit processing. The DAC is configured as an R-2R ladder. It is a 24-bit network using 0.01% resistors although these resistors can not easily provide a resolution higher than 14 bits.

The User Explains

At TOTALDAC, we build a DAC and digital crossover for high-end audio systems based on an FPGA and discrete resistors. The TOTALDAC board is assembled in an ISO 9001-certified factory in France and each board is inspected and its sound quality tested before shipping.

As I wanted to build the best sounding audio DAC, I tested the sound quality delivered by a number of mass-produced DAC chips from several well-known companies, including Analog Devices, TI, Philips, Cirrus Logic, Wolfson, and AKM.

Some of them were new old stock (NOS) chips known for their nice sound such as the TDA1541, TDA1545 (used in CD723), TDA1543, PCM56, AD1852 (used in Teac VRDS 25x), CS4328 (used in Helios Stargate), PCM1702 (used in many high-end CD players in the past), and PCM1704U-K.

Some were really nice, but never very accurate. I listened to them with and without oversampling whenever possible. I used a Pacific Microsonic PDM100 HDCD digital filter, one of the best digital filters available. I also listened to many new DAC chips from TI and Analog Device in particular. These usually required microcontroller programming. The sound was often a bit metallic. Lastly, I listened to the sound quality from a discrete R2R DAC made of simple 1% resistors. The musicality was there but some accuracy was missing. This was the starting point of my ultimate DAC solution.

After two years, five PCB revisions, and other improvements to the FPGA, I finally settled on the VSRJ 0.01% resistor. Although 96 discrete resistors per channel are used, the signal path is actually very short, going through the 0.01% resistors, into a C-L-C filter, through a capacitor, and then into the potentiometer.

Fig. 1: Each channel uses 96 pieces of VPG Foil Resistors' VSRJ 0.01% Bulk Metal Foil resistors

Once the prototype worked as expected, I contacted VPG Foil Resistors Europe to choose the most appropriate Bulk Metal foil resistors. While the VAR series resistors – components specifically designed for audio applications – may have been the absolute ideal resistors to be used, the VSR series through-hole resistors offered sufficiently impressive performance combined with a preferred price tag. That is of particular interest due to the high number of resistors used per channel. To my knowledge, no other DAC for the high-end audio market uses a 24-bit foil ladder configuration. The Bulk Metal Foil resistive technology is the absolute key factor for the success of this design.

Fig. 2: The 3-way TOTALDAC board uses 288 of these resistors.

Measurements

Figure 3 shows the quality of the DAC for an extremely low amplitude signal such as concert hall long reverberation. The noise floor on graphic FFT is as low as -156 dB, although 0 dB is really the maximum DAC level (1.6 Vrms). The measurements were done by a Rohde & Schwarz UPL audio analyzer. Only the second order harmonic distortion is visible, and is only at -126dB. The distortion would be lower with an operational amplifier, but I preferred the sound created by discrete transistors without global feedback. Some noise is visible at low frequencies, it is due to the mains power supply. A power supply regulator would remove this noise but I prefer the sound without global feedback in the power supply for the analog section.

Fig. 3: Spectrum of a 1 kHz sinewave at -80dBFs with the power supply and buffer board

Contact Information

Vincent Brient
Inventor Chief Engineer
TOTALDAC
Rennes,France
URL: http://www.totaldac.com/
Email: vincent_brient@yahoo.fr

Tags: vishay_foil_resistors, precision, digital_to_analog, applications, audio, engineer, var_resistors, pacific_microsonic, design_engineers, dac, totaldac, resistors, bulk_metal, noise, foil_technology, vsr_series, case_study_program

CASE STUDY: Developing a Multi-Channel DAC for High-End Audio Applications

Tomhazan1 — Thu, 11 Sep 2025 06:14:13 GMT

Revision 5 posted to Documents by Tomhazan1 on 9/11/2025 6:14:13 AM

CASE STUDY: Developing a Multi-Developing Multi-Channel DAC for High-End Audio | VPG Foil Resistors

Author: Vincent Brient, Inventor Chief Engineer, TOTALDAC

Industry/ Application Area

High-End Audio

Product Used

VSR series Bulk Metal^® Foil resistors

Description of Case Study

The Challenge

Our goal was to create a no-compromises DAC and digital crossover with 69-bit processing. The DAC is configured as an R-2R ladder. It is a 24-bit network although 0.01% resistors can not easily give a resolution higher than 14 bits.

The User Explains

Fig. 1: Each channel uses 96 pieces of VPG Foil Resistors' VSRJ 0.01% Bulk Metal Foil resistors

Fig. 2: The 3-way TOTALDAC board uses 288 of these resistors.

Measurements

Fig. 3: Spectrum of a 1 kHz sinewave at -80dBFs with the power supply and buffer board

Contact Information

Vincent Brient
Inventor Chief Engineer
TOTALDAC
Rennes,France
URL: http://www.totaldac.com/
Email: vincent_brient@yahoo.fr

11 Reasons Engineers Trust Bulk Metal Foil Resistors

Tomhazan1 — Wed, 10 Sep 2025 11:00:53 GMT

Current Revision posted to Documents by Tomhazan1 on 9/10/2025 11:00:53 AM

Why Engineers Choose Bulk Metal® Foil – Proven. Precise. Enduring.

At the heart of today’s most demanding analog and digital designs lies the unmatched performance of Bulk Metal® Foil Resistor Technology—a legacy born from innovation and trusted by engineers worldwide. This brochure outlines 11 compelling reasons why this technology, developed by VPG Foil Resistors, remains the benchmark in high-precision resistor solutions.

From ultra-low TCR and long-term load life stability to low thermal EMF and superior ESD resistance, each reason underscores the engineering value of foil resistors in critical applications. Whether used in aerospace, semiconductor testing, instrumentation, or medical devices, these resistors consistently outperform other technologies in terms of precision, stability, and environmental resilience.

With proven reliability across decades, including flight-qualified and hermetically sealed designs, VPG Foil Resistors enable tight tolerance, predictable drift, and thermal behavior control—making them essential in any environment where accuracy is non-negotiable.

Read the brochure here: 11 Reasons to Choose Bulk Metal^® Foil Technology for your Circuit

Tags: temperature_coefficient_resistance, resistance, precision, load_life_stability, resistors, VPG Foil Resistors, bulk_metal, high-precision, foil_technology

11 Reasons Engineers Trust Bulk Metal Foil Resistors

Tomhazan1 — Tue, 09 Sep 2025 08:19:39 GMT

Revision 4 posted to Documents by Tomhazan1 on 9/9/2025 8:19:39 AM

Why Engineers Choose Bulk Metal® Foil – Proven. Precise. Enduring.

Read the brochure here: 11 Reasons to Choose Bulk Metal^® Foil Technology for your Circuit

Tags: temperature_coefficient_resistance, resistance, precision, load_life_stability, resistors, VPG Foil Resistors, bulk_metal, high-precision, foil_technology

11 Reasons Engineers Trust Bulk Metal Foil Resistors

Tomhazan1 — Tue, 09 Sep 2025 08:18:27 GMT

Revision 3 posted to Documents by Tomhazan1 on 9/9/2025 8:18:27 AM

Why Engineers Choose Bulk Metal® Foil – Proven. Precise. Enduring.

Read the brochure here: 11 Reasons to Choose Bulk Metal^® Foil Technology for your Circuit

Tags: precision, load_life_stability, resistors, VPG Foil Resistors, bulk_metal, high-precision, foil_technology

11 Reasons Engineers Trust Bulk Metal Foil Resistors

Tomhazan1 — Tue, 09 Sep 2025 08:17:26 GMT

Revision 2 posted to Documents by Tomhazan1 on 9/9/2025 8:17:26 AM

Why Engineers Choose Bulk Metal® Foil – Proven. Precise. Enduring.

Read the brochure here: 11 Reasons to Choose Bulk Metal^® Foil Technology for your Circuit

Tags: VPG Foil Resistors, bulk_metal

11 Reasons Engineers Trust Bulk Metal Foil Resistors

Tomhazan1 — Tue, 09 Sep 2025 08:17:03 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 8:17:03 AM

Why Engineers Choose Bulk Metal® Foil – Proven. Precise. Enduring.

Read the brochure here: 11 Reasons to Choose Bulk Metal^® Foil Technology for your Circuit

VFR Resistors: Unrivaled Stability with Bulk Metal®︎ Foil Technology

Tomhazan1 — Tue, 09 Sep 2025 07:57:27 GMT

Current Revision posted to Documents by Tomhazan1 on 9/9/2025 7:57:27 AM

Precision You Can Rely On — Proven. Stable. Trusted.

VPG Foil Resistors leads the industry in ultra-precision resistor technologies, built on the legacy of Bulk Metal^® Foil innovation introduced by Dr. Felix Zandman in 1962. Designed to meet the most stringent demands in aerospace, defense, medical, metrology, industrial, and telecom markets, our solutions deliver unmatched accuracy, long-term stability, and thermal reliability.

Our resistor portfolio includes:

Z1-Foil^® resistors with TCR as low as ±0.2 ppm/°C
Low-ohmic current sense resistors with Kelvin 4-terminal designs
Hermetically sealed resistors for mission-critical applications
Military-grade and space-qualified components (DLA, EEE-INST-002, ESA, CECC)
Matched resistor networks and custom chip arrays
Trimming potentiometers and hybrid circuit chips

With offerings across surface-mount, through-hole, and custom packaging configurations, VPG Foil Resistors supports engineers in achieving extreme accuracy in measurement and control — even under severe temperature, load, and environmental conditions. Every product is backed by decades of research, application knowledge, and field-proven performance in the world’s most demanding systems.

VPG Foil Resistors — For when precision isn’t optional.

Read the brochure here: VFR Bulk Metal^® Foil Ultra-Precision Resistors Brochure

Tags: Hermetically Sealed Resistors, Surface Mount Foil Resistors, Voltage Dividers and Resistor Networks, resistors, VPG Foil Resistors, Power Current Sense Resistors, bulk_metal, Military and Space (AMS), avionics, high-precision, current_sensing, foil_technology

APR Series: Standardized Precision, Delivered Fast

Tomhazan1 — Tue, 09 Sep 2025 07:55:21 GMT

Current Revision posted to Documents by Tomhazan1 on 9/9/2025 7:55:21 AM

Reliable. Standardized. Ready-to-Use.

APR – Standardized Precision Resistors by VPG Foil Resistors deliver dependable performance for high-volume, cost-effective applications across industrial, automotive, power, and communications sectors. Designed for when “better is good enough,” the APR portfolio includes metal strip, foil, thin film, and thick film technologies—offered in made-to-stock formats that balance price and performance.

From AEC-Q200 compliant SMD current-sense resistors to high-voltage leaded wirewound models, APR resistors are available in tape-and-reel, axial, radial, and PCB module configurations. These resistors support resistance ranges from micro-ohms to tera-ohms and feature stability under load life, with TCRs as low as ±3 ppm/°C and tolerances down to ±0.005%.

APR resistors are engineered for EV charging, 5G infrastructure, power modules, and instrumentation, providing reliable measurement, thermal stability, and delivery agility.

Read the brochure here: APR Standardized Precision Resistors Brochure

Tags: Surface Mount Foil Resistors, resistors, VPG Foil Resistors, Power Current Sense Resistors, bulk_metal, high-precision, foil_technology

Precision for the Digital World: Resistor Solutions for Telecom & Semiconductors

Tomhazan1 — Tue, 09 Sep 2025 07:53:46 GMT

Current Revision posted to Documents by Tomhazan1 on 9/9/2025 7:53:46 AM

VPG Foil Resistors brings unmatched precision to the world of telecommunications and semiconductor manufacturing. By leveraging proprietary Bulk Metal® Foil technology, these resistors ensure low inductance, ultra-low TCR, and minimal signal noise—enabling the delivery of pure, high-speed data transmission across critical infrastructure.

Designed to meet the challenges of high-frequency communications, ATE systems, and precision test environments, VPG’s resistor solutions support consistent signal integrity and robust thermal stability across a wide range of formats. These include surface-mount and leaded resistors, power current-sense devices, voltage dividers, and hermetically sealed networks.

The VPG portfolio enables applications such as 5G base stations, fiber-optic networks, industrial IoT, GPS, data centers, medical electronics, and semiconductor ATE platforms. With Kelvin 4-terminal designs, wraparound and flip-chip configurations, and power handling up to 500 W, each solution is built for reliability and engineered for the future.

From unmatched stability to precise customization and long-term load life, VPG Foil Resistors continue to serve as the backbone for next-generation electronic technologies.

Read the brochure here: Telecommunications & Semiconductors Brochure

Precision for the Digital World: Resistor Solutions for Telecom & Semiconductors

Tomhazan1 — Tue, 09 Sep 2025 07:52:28 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 7:52:28 AM

From unmatched stability to precise customization and long-term load life, VPG Foil Resistors continue to serve as the backbone for next-generation electronic technologies.

Read the brochure here: Telecommunications & Semiconductors Brochure

Alpha Electronics Standard Resistors & Decade Boxes

Tomhazan1 — Tue, 09 Sep 2025 07:40:08 GMT

Current Revision posted to Documents by Tomhazan1 on 9/9/2025 7:40:08 AM

Alpha Electronics – part of the VPG Foil Resistors product group – is renowned for delivering ultra-precision resistor solutions engineered for the most demanding analog and digital applications. Manufactured exclusively in a fully automated facility in Akita, Japan, Alpha’s Bulk Metal® Foil resistors represent the pinnacle of consistency, reliability, and thermal stability.

This broad portfolio includes discrete resistors and resistor networks in surface-mount and leaded configurations, power current sense devices with Kelvin connections, hermetically sealed options for extreme environments, and temperature-sensitive elements with tightly defined TCR characteristics. With a typical TCR as low as ±0.2 ppm/°C and resistance tolerances down to ±0.005%, these resistors are ideal for applications where drift, noise, or instability cannot be tolerated.

The offering also features high-performance thin film resistors and thermosensitive models, all designed to maintain exceptional load life stability and ultra-low thermal EMF, even under harsh environmental conditions. Alpha Electronics continues to advance its product range for emerging needs in automatic test equipment, semiconductor measurement, precision weighing, aerospace, communications, and medical technologies

Read the brochure here: Alpha Electronics Standard Resistors & Decade Boxes

Tags: Surface Mount Foil Resistors, resistors, VPG Foil Resistors, Power Current Sense Resistors, bulk_metal, high-precision, foil_technology

Alpha Electronics Standard Resistors & Decade Boxes

Tomhazan1 — Tue, 09 Sep 2025 07:38:34 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 7:38:34 AM

Read the brochure here: Alpha Electronics Standard Resistors & Decade Boxes

APR Series: Standardized Precision, Delivered Fast

Tomhazan1 — Tue, 09 Sep 2025 07:09:10 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 7:09:10 AM

Reliable. Standardized. Ready-to-Use.

APR resistors are engineered for EV charging, 5G infrastructure, power modules, and instrumentation, providing reliable measurement, thermal stability, and delivery agility.

Read the brochure here: APR Standardized Precision Resistors Brochure

VFR Resistors: Unrivaled Stability with Bulk Metal®︎ Foil Technology

Tomhazan1 — Tue, 09 Sep 2025 06:54:22 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 6:54:22 AM

Precision You Can Rely On — Proven. Stable. Trusted.

Our resistor portfolio includes:

Z1-Foil^® resistors with TCR as low as ±0.2 ppm/°C
Low-ohmic current sense resistors with Kelvin 4-terminal designs
Hermetically sealed resistors for mission-critical applications
Military-grade and space-qualified components (DLA, EEE-INST-002, ESA, CECC)
Matched resistor networks and custom chip arrays
Trimming potentiometers and hybrid circuit chips

VPG Foil Resistors — For when precision isn’t optional.

Read the brochure here: VFR Bulk Metal^® Foil Ultra-Precision Resistors Brochure

Powertron Resistors: Precision Meets Power in Every Application

Tomhazan1 — Tue, 09 Sep 2025 06:36:32 GMT

Current Revision posted to Documents by Tomhazan1 on 9/9/2025 6:36:32 AM

Powertron, a product brand under VPG Foil Resistors, delivers a diverse range of high-power, high-precision resistor solutions built for industrial, automotive, energy, and power electronics applications. Engineered with advanced metal foil and metal strip technologies, Powertron resistors are optimized for demanding thermal, mechanical, and electrical conditions — ensuring long-term accuracy and stability under load.

Key offerings include:

Low-ohmic current sense resistors with values as low as 0.0005 Ω
High-power SMD and through-hole resistors, capable of dissipating up to 1000 W
Hermetically sealed and housed modules for rugged environments
Kelvin 4-terminal designs to ensure precision and low thermal EMF
Custom resistor networks for space-saving and efficiency-driven designs

Powertron’s unique product families such as PRND, PCF, PFS, UMR, and WDBR deliver performance-critical features such as low TCR (as low as ±5 ppm/°C), tight tolerance (down to ±0.01%), and high surge resistance. These resistors are ideally suited for applications in power converters, battery charging, current feedback loops, energy storage, and automotive ECUs.

With flexible form factors, AEC-Q200 qualified parts, and customizable layouts, Powertron combines compact design with high thermal and electrical resilience to meet the next generation of power and precision challenges.

Read the brochure here: Powertron CuNiMn, CuMnSn and NiCr Resistors Brochure

Tags: resistors, VPG Foil Resistors, high-precision, current_sensing

Powertron Resistors: Precision Meets Power in Every Application

Tomhazan1 — Tue, 09 Sep 2025 06:19:56 GMT

Revision 1 posted to Documents by Tomhazan1 on 9/9/2025 6:19:56 AM

Key offerings include:

Low-ohmic current sense resistors with values as low as 0.0005 Ω
High-power SMD and through-hole resistors, capable of dissipating up to 1000 W
Hermetically sealed and housed modules for rugged environments
Kelvin 4-terminal designs to ensure precision and low thermal EMF
Custom resistor networks for space-saving and efficiency-driven designs

Mission-Critical Precision: Aerospace & Defense Qualified Resistors Brochure

Tomhazan1 — Mon, 08 Sep 2025 13:22:49 GMT

Current Revision posted to Documents by Tomhazan1 on 9/8/2025 1:22:49 PM

VPG Foil Resistors delivers a proven portfolio of military-qualified and space-grade precision resistors, engineered to perform reliably under the most demanding aerospace and defense conditions. Powered by our proprietary Bulk Metal® Foil technology, our solutions offer unmatched long-term stability, ultra-low TCR, and tight tolerance—even in extreme environments spanning −65°C to +175°C.

Our range includes:

QPL-approved through-hole and surface-mount resistors (MIL-PRF-55182, MIL-PRF-55342, MIL-PRF-32663)
EEE-INST-002 tested parts, compliant with NASA Goddard and DLA requirements
Voltage dividers, precision trimming potentiometers, and resistor networks
Kelvin-connected current sense resistors and hermetically sealed modules
Custom high-stability devices listed on EPPL and CECC standards

Products such as the RNC90 series, Z201, and FRSM/SMR series are extensively qualified with full destructive and 100% screening per space and military standards. Our trimmers (e.g., RJ26), voltage dividers, and PRND sealed networks deliver consistent results where every ohm matters.

From satellites and avionics to defense systems and guided platforms, our high-reliability resistors are tested and trusted to meet mission-critical expectations over time and temperature.

Read the brochure here: Aerospace & Defense Qualified Resistors Brochure

Tags: precision, through hole resistors, Surface Mount Foil Resistors, VPG Foil Resistors, bulk_metal, Military and Space (AMS), avionics, high-precision, current_sensing, foil_technology

Accuracy You Can Measure: High-Precision Current Sense Resistors Brochure

Tomhazan1 — Mon, 08 Sep 2025 12:55:10 GMT

Current Revision posted to Documents by Tomhazan1 on 9/8/2025 12:55:10 PM

VPG Foil Resistors offers a specialized range of current sense resistors designed for precise, high-efficiency power measurement and control across a wide range of applications. Built with Z1-Foil®, Bulk Metal^® Foil, and metal strip technologies, these resistors provide excellent thermal performance, long-term stability, and minimal resistance drift — even in dynamic load conditions and high-temperature environments.

Our portfolio spans:

4-terminal Kelvin-connected foil resistors with resistance values as low as 0.3 mΩ
High-power surface-mount current sensors up to 12 W in compact packages
Hermetically sealed modules for critical applications such as aerospace and defense
Custom current shunt assemblies tested up to ±8000 A and ±20000 A
Precision matched resistor networks to improve circuit efficiency and accuracy

These resistors are optimized for battery management systems (BMS), power conversion, motor drives, industrial control, EV platforms, data centers, and instrumentation. Their excellent load-life stability, low TCR, and thermal EMF performance help designers meet tight error budgets and achieve accurate power and current measurement without sacrificing reliability.

Whether your application demands long-term stability, low inductance, or high-power handling — VPG’s current sense resistors deliver the performance needed to monitor and control power with confidence.

Read the brochure here: High Precision Current Sense Resistors Brochure

Tags: through hole resistors, Surface Mount Foil Resistors, VPG Foil Resistors, Power Current Sense Resistors, high-precision, current_sensing, foil_technology

Accuracy You Can Measure: High-Precision Current Sense Resistors Brochure

Tomhazan1 — Mon, 08 Sep 2025 12:53:02 GMT

Revision 2 posted to Documents by Tomhazan1 on 9/8/2025 12:53:02 PM

Our portfolio spans:

4-terminal Kelvin-connected foil resistors with resistance values as low as 0.3 mΩ
High-power surface-mount current sensors up to 12 W in compact packages
Hermetically sealed modules for critical applications such as aerospace and defense
Custom current shunt assemblies tested up to ±8000 A and ±20000 A
Precision matched resistor networks to improve circuit efficiency and accuracy

Read the brochure here: High Precision Current Sense Resistors Brochure

Tags: Surface Mount Foil Resistors, VPG Foil Resistors, Power Current Sense Resistors, high-precision, current_sensing, foil_technology