Digital Tube

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Digital Tube
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Senior Design Project 08

• Tube Emulation Through Digital Design
• Abstract
• Tube amplifiers are used in high end audio
  equipment to reproduce sound that is unmatched in
  transistor based amplifiers.
• Our goal is to make a digital equivalent to this
  unmatched sound produced by a specific vacuum
  tube.
• This could possibly be the new evolution in
  amplifier design.

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Group Members

• Andy Zerngast
• Team Leader
• Adil Hanine
• Neural Networks
• Liang Jiang
• Signal Processing
• Shane Hodges
• Programmer
• John Harrison
• Advisor

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Introduction
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Vacuum Tube

• A vacuum tube consists of electrodes in a vacuum
  within an insulating, temperature-resistant
  envelope.
• When hot, the filament releases electrons into
  the vacuum.

Glass Envelope
Plate (Anode)
Filament (Cathode)
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Vacuum Tube

• If the plate is positively charged relative to
  the filament these electrons will be drawn to a
  metal plate inside the envelope.
• The result is a flow of electrons from filament
  to plate.

Glass Envelope
Plate (Anode)
Filament (Cathode)
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Vacuum Tube

• This is not possible in the reverse direction
  because the plate is not heated and cannot emit
  electrons.
• This is a simple diode.

Glass Envelope
Plate (Anode)
Filament (Cathode)
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High End Audio

• A true high end audio system would create the
  illusion of the listener being present at the
  audio performance.
• High End Audio systems are generally very
  expensive and are not for the every-day consumer.
• Many high end systems use vacuum tubes.

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High End Audio

• Qualitative attributes of a high end system
• accuracy vs. warmth
• tonal color vs. speed
• timbre (sound quality)
• depth
• clarity

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Tube Amplifier

• THX Intro without pre-amp
• THX intro with pre-amp

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Digital Tube

• Input and Output test signal
• Neural Network
• Circuit Designed for miniature 9 pin socket

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Project Requirements
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Keys to Groups Success

• Vacuum Tubes and Tube Amplifier Theory
• Pre-Amp Construction
• ELVIS System
• Neural Networking
• Programming
• Circuit Design
• Manufacturing

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Keys to Products Success

• Tube Sound
• Aesthetics
• Size
• Programmable Tube (Optional)

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Tube Sound

• Tube sound is the characteristic sound
  traditionally associated with a tube-based audio
  amplifier.
• All practical amplifiers distort to some degree
  some audiophiles prefer the sound that is
  produced by the distortion characteristics of
  tube-based amplifiers.
• The audible significance of measurable effects on
  signals is a continuing debate among audiophiles.

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Distortion concept

• There are many types of distortion, but the type
  most referred to in "tone creation" is amplitude
  distortion. This is caused when an amplifying
  device, such as a tube or transistor, is
  conducting as much current as it possibly can or
  if it has gone into cut off with no current
• This can sound gritty and nasty, or smooth and
  beautiful depending on the device being used and
  the level of conduction.

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Aesthetics

• Mounted inside a tube
• Lighted

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Size

• Small
• Approximate size of the 12au7

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Programmable Tube (Optional)

• Programmable box
• Match any tube
• Push button programming

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Design
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A/D/A Chip
Micro Processor
A/D Converter
D/A Converter
Amp
Preamp Amplifier
Input signal
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Economic Impact

• The digital amplification technology is durable
  and efficient.
• Cheaper alternative to vacuum tubes because it
  will last longer and less frequent to replace.

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Social Constraints

• Consumers may be reluctant to purchase the
  product because of unknown manufactures.
• Buyers may also be unsure of the quality and the
  reliability of the design because there is no
  other design like it

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Sustainability

• Product
• The digital tube will be designed to last the
  lifetime of the amp
• Product Future
• Programmable tube
• Adapting it to tubes other then 12AU7
• Integration into Amplifiers

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Validation and Analyses

• Validation
• Mathematical
• RMS Error as determined by Neural Networks
• Graphical
• Graphical analyses
• Audible
• Sound the same

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Time Line Sheet
Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007
Other Design Modifications
Team1 Program Microchip for Emulation
Project Report Due
Team2 Circuit Product Design
Business Plans
Open House Event
Semester 2
6th Month Feb. 2008
7th Month Mar. 2008
5th Month Jan. 2008
8th Month Apr. 2008
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Seeking an advisor (John) for help w/ our project
• Discussing the ideas of the new design
• Vacuum tube (12AU7) chosen for our start point
• Plans for the project start point
• Sponsorships
• Gathering the possible techniques to make the
  design
• Talk about Commercial viability when the
  product is made

Getting Started
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Plans for the future presentation of the open
  house event
• Build splitter to switch between tube and
  emulator
• Write up what all the components are for doing
  this project
• Pre-Amp (w/ an upgrade kit if financially
  possible)
• Evaluation Board (w/ chip set)
• Amplifier
• Pair Speakers (w/ 93dB or better sensibility)

Brainstorming
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Group Communication

• Homepages and link (http//cratel.wichita.edu/crat
  el)
• Wiki Homepage for project
• Group member page for contact info and self
  portfolio
• Group blog for updates and group references
• Group meeting at Cratel Lab (Johns office)
• Every Friday at 1230pm-330pm
• Every Monday at 1230pm-130pm

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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• List pros and cons of vacuum tube
• Operation and Information
• Varieties of Vacuum tubes
• 12AX7
• 12AU7
• Vacuum tube basics
• Tube sounds
• Mathematical Models

Research of Vacuum Tube Amplifiers
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Soldering Introduction
• Team successfully built 2 LOGO Chips
• Learned how to correctly identify proper solder
  joints
• Learned the importance of color codings on
  resistors
• Learned how to correct soldering mistakes
• Experimented with different soldering tips
• Experimented with different techniques

Soldering Lessons
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Researched Pre-Amps
• Prices
• DYI vs Prebuilt
• Tube types
• Based on amount of available information and
  support
• Chose Foreplay III by Bottlehead
• Requested funding from WSU
• Funding was approved by IEEE
• Group needs to speak to Dr. Skinner before
  ordering
• Sockets
• Researched sockets
• Switch
• Voltage and Current Measurements
• Concluded that we need to wait for Pre-Amp before
  ordering any sockets

Kit Selection Orders
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Obtain signals for Computer Analysis
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Arrival of Pre-Amp
• Group building the pre-amp together
• Three group meeting section were spent to finish
  the job ( Loads of careful soldering job
  required)
• Check resistance and thorough completion of
  device
• Testing of the Pre-Amp
• Test w/ ipod
• Compared the sound clarity w/ and w/o of the
  pre-amp

Pre-Amp Assembling
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Bottlehead Foreplay III Kit
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Signal Process and Program
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Analog to Digital to Analog Converters
• Specifications
• Economical
• Fast enough to process audio signal
• Small in size
• Comes with development kit
• Mathematical Modeling/ Neural Network phase
• Economical
• Easy computer interface
• High quality (can adequately handle audio
  signals)
• Implementation phase
• Economical
• Small in size
• High quality (can adequately handle audio
  signals)
• Programmable

Emulation Device Selection
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Signal Process and Program
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Neural Networks
• Spoke with experts Dr. Steck (AE Dept.)
• Find out about integration with A/D converters
• Experiment with PD
• real-time graphical programming environment for
  audio and graphical processing
• Learn to use pd w/ our advisor John Harrison

Team1 Emulation Training Software
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Signal Process and Program
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Spoke with Derek Ruth in the WSU Entrepreneur
  Department
• Put together project packet and literature
• Speak with different companies about sponsorship
• Speak with colleague about and financial
  assistance

Sponsorship
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Business Plans
Research of Vacuum Tube Amplifiers
Emulation Device Selection
Group Presentation
Team Task Assignment
Soldering Lessons
Team1 Emulation Training Software
Sponsorship
Brainstorming
Kit Selection Orders
Pre-Amp Assembling
Team2 Signal Process and Program
Getting Started
Patents Library search
Semester 1
2nd Month Oct. 2007
1st Month Sept. 2007
3rd Month Nov. 2007
4th Month Dec. 2007

• Make a business and consumer friendly website
• Elevator pitch

Business Plans
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Other Design Modifications
Team1 Program Microchip for Emulation
Project Report Due
Team2 Circuit Product Design
Business Plans
Open House Event
Semester 2
6th Month Feb. 2008
7th Month Mar. 2008
5th Month Jan. 2008
8th Month Apr. 2008
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Acknowledgments

• John Harrison
• Derek Ruth
• Dr. Steck
• Steven Skinner
• Bottlehead