Tape Recorder Class

[ironbut]

There was a posting on the Ampex list from Dale Manquen regarding a tape recorder class that he'd worked up for college level engineers many moons ago. If you don't know of Dale, you'd do well to check out his site from end to end. Really interesting stuff. Years ago when I first read about this class (I believe it was offered at Cal State Northridge?) I was excited at the prospects of taking but of course, the class had been dropped from the catalog years before I heard about it.

Well, back to present days, Dale is looking to offer this class around the country.
Here is his posting;

"Would anyone on the list be interested in a two or three day intensive
class in the theory and engineering of audio tape recorders?  This idea
came up at the AES convention, and I am hoping to determine the
interest/marketability of such a class.

The topics would include the record, playback and erase functions, head
manufacturing, tape manufacturing, transport design and diagnosis, and
related topics.  I originally developed the course as a 40-hour program,
but I have since condensed it to about 24 hours.  We could do it in 2
long days or 3 more leisurely days.

I would try to hold the class in or near a cluster of about 15 students,
probably hosted by someone locally.  Steve Puntolillo has expressed
interest in hosting a class in the NY/NJ area.

The cost is yet to be determined since I don't know where, how long, or
number of students, but I am just hoping to wind up with a nice paid
trip with a few extra days for visiting.

I will appreciate any comments or suggestions."

Dale Manquen at MANCO
1694 Calle Zocalo
Thousand Oaks, CA 91360
(805) 529-2496
[email protected]
www.manquen.net

I've contacted him to ask what he thought a ball park cost would be, and he guessed it would be in the $400 range (depending a great deal on the attendance, venue costs, and other expenses.
So, if you guys are as interested as I am to take a this class and pick Dale's brain (I'm not sure if he's going to be at every one), give him an email.

[ironbut]

Here's some more info regarding Dale's class. Here's the original class outline (bear in mind this was for a 40 hour class so it will be modified somewhat).
The class size will be a minimum of 6 persons with a max of 15. So far, it looks as if the 2 10 hour day or 3 day formats will be up to the participants.
It will be mostly lecture with some videos to give Dale a break.

TAPE RECORDER THEORY AND MAINTENANCE
Taught by Dale Manquen

History of the Course

In the mid '70's I had the opportunity to help Jack Williams of Pacific Recorders and Engineering in San Diego with the checkout of several new MCI tape recorders that he was delivering to his customers.  Jack's sales to the broadcast industry were growing rapidly and he needed to upgrade his technical staff to support this higher level of activity.  He asked me to put together a comprehensive training program that would be suitable for his technicians and his customers' techs.

My approach was to concentrate on the underlying principles and fundamentals that form the common basis for all magnetic recorders.  If the student knew what the recorder was supposed to do, then he could pinpoint the specific circuit and component that did each task on his brand and model of recorder.  This approach was in sharp contrast to the tape machine manufacturers' courses that stressed how to fix only their machine with instructions such as "Adjust R26 1/4 turn ?"

The general coverage provides the tools to deal with any brand and type of magnetic tape recorder, including new models that are introduced in the future.  My students have easily made the transition to digital recorders by applying the same fundamental concepts.

We learn how to unravel to complicated ball of interacting parts that form a tape recording system.  We learn how to isolate problems due to heads, the tape transport, signal electronics circuits and even the tape stock.

The course emphasizes preventive maintenance.  How can you spot the small changes that will become a major problem if not corrected quickly?  The real value of a service technician is not in how fast he can fix something once it has broken.  It is how seldom his equipment fails.  Don't you want your auto mechanic to help you avoid car breakdowns rather than choosing the mechanic with the fastest tow truck?

My career has provided me with a diverse background that provides many first-hand anecdotes to illustrate the topics.  I have designed tape recorders from the ground up - both mechanisms and electronics.  I have worked in the Ampex Magnetic Tape Division.  I have designed and built specialized test equipment for analyzing recorders.  And, yes, I have worked in film scoring studios and on remote recording crews where breakdowns are incredibly expensive.

Each offering of the course is tailored to the group of students and their specific interests.  The examples are chosen from the machines that the students must maintain.  The original offerings were 40-hour courses, but I have since developed a shorter 32-hour version.  Slides, overhead transparencies and real parts from recorders augment the lectures.  We even re-lap a worn head in class.

Over the years, I have taught this course many times at venues that include L.A., San Diego, Dallas and New York City.  My graduates include some of the chief engineers of major studios and some of the best freelance techs.  And I still get an occasional call from a student who wants to talk over a specific problem that he has encountered.  Would you care to join this rather exclusive group?

Outline of Course
A. Magnetic Recording Theory
Basic electromagnetics - Flux > Voltage
Ring core heads
Magnetic particles
Magnetic tape
Manufacturing
Performance characteristics
Testing
Playback or reproduction
Wavelength vs. frequency
Output vs. frequency
Spacing loss
Gap length loss
Azimuth loss

Thickness loss
Contour effect
Fringing
Crosstalk and guardbands
Eddy currents
Shielding
Track configurations vs. signal-to-noise
The flux loop
Recording Hysteresis curves
High frequency bias
Self demagnetization
Distortion
Erasure
Bulk degaussers
Double-gap erase heads
Printthrough
Linearizers
Magnetic head designs
Ferrite vs. metal Construction
Relapping
Undercutting
Adjustments
Azimuth vs. phasing
Zenith
Height
Racking
Wrap
Tape transports
Types of motors
1) Synchronous a. c.
2) Induction a.c.
3) Shunt d.c.
4) Series d.c.
Brushless d.c.
Pabst motor
Printed circuit motor
Constant velocity drives
1) Wow vs. flutter
2) Line frequency control
3)Servo
Tachometers
Velocity vs. phase lock
Constant tape tension drives
Capstan derived tensions
Fixed tension
Two point approximation
Open loop "calculated"
Direct sensing
Guides
Edge guides
Flanged guides
Rotary guides
Solenoids
Flat bottom linear
Taper bottom linear
Rotary
Torquers
Bearings
Ball Bearings
Bushings
Dashpots
Control logic
Digital tape transports
Wavelength and signal-to-noise tradeoffs for digital recording
Longitudinal multitrack digital recorders
Helical scan digital recorders
A/D and D/A considerations
Clocking, jitter, flutter and dropouts
Error detection and correction
Circuits
Understanding op amps
Power supplies
Motor drivers
Reproduce Circuits
Equalization standards
 Noise problems
 Head resonance
 The flux loop
 Phase rotation networks
Record circuits
Equalization
Head driver
Predistortion or linearizing
Headroom
Bias/erase circuits
Oscillators
Push-pull transformer coupled
Mixing and tuning
Signal and deck logic
Basics of logic
Truth tables
Gates, latches, flip-flops, and counters
Binary numbers
Relays vs. FET's
Motion/direction sense
Power control
Specific examples from various manufacturers
Test instruments and calibration procedures
Test Equipment
Oscillator
Oscilloscope
Meter
Harmonic/IM distortion
Wave analyzer
Flutter meter
Equalized flux loop
Degausser
Monitor
Alignment tapes
Tape tension gauge
Magnetometer
Micrometer/Caliper/Dial Indicator
Alignment
Transport
Tension
Speed
Heads
Reproduce level and equalization
Bias
Record level, equalization, & predistortion
Erase
General troubleshooting tips
Bibliography

HANDBOOK FOR SOUND ENGINEERS  2nd Edition edited by Glen Ballou Howard W. Sams & Co.  See chapters on Magnetic Recording and Playback and Digital Recording and Playback by Dale Manquen
THE COMPLETE HANDBOOK OF MAGNETIC RECORDING by Fin Jorgensen Tab Books
MAGNETIC RECORDING HANDBOOK by Marvin Camras, Van Nostrand Reinhold
STANDARD TAPE MANUAL by Morrison, Robert K.  R.K. Morrison Illustrative Materials, 819 Coventry Rd., Kensington, CA 94707
THE PHYSICS OF MAGNETIC RECORDING by C Denis Mee  John Wiley & Sons, NY 1964
MAGNETIC RECORDING VOL.II COMPUTER DATA STORAGE  by C. Denis Mee and Eric D. Daniel, McGraw Hill
MAGNETIC RECORDING VOL.III VIDEO, AUDIO, AND INSTRUMENTATION RECORDING by C. Denis Mee and Eric D. Daniel, McGraw Hill
MAGNETIC TAPE RECORDING by Skip W. Athey, NASA SP-5038 January 1966.
MAGNETIC TAPE RECORDING by Spratt, H.G.M. D. Van. Nostrand Co, Inc. Princeton, NJ 1964
MAGNETIC RECORDING IN SCIENCE & INDUSTRY by Pears, C.B., Reinhold Publishing Corp. NY 1967
PRINCIPLES OF DIGITAL AUDIO by Ken C. Pohlmann, SAMS
LOW NOISE ELECTRONIC DESIGN by Motchenbacher, C.D. & Fitchen, F.C., John Wiley & Sons NY 1973

Videotapes
A Chronology of American Tape Recording produced by Dale Manquen for the Audio Engineering Society
An Afternoon with Jack Mullin, AES
Audiotapes
LA AES Section Grounding Workshop, AES