Section 1; Amplifier Basics - 15 Articles


 001
Prev

7.0 MB

76
Pgs

Download all the articles in Volume 1; Section 1
Collated into one bookmarked PDF.
   

 

 

 

002
Prev

800
KB

4
Pgs

Puzzled About Amplifiers ? - Norman H. Crowhurst
Is a triode amplifier better than a pentode amplifier, or vice versa? The author shows that either type of tube can incorporated into an excellent amplifier if the design is correct -- and then he tells about some of the design problems.

 

 

 

 

 

003
Prev

1.1
MB

6
Pgs

Amplifiers - Edgar M. Villchur
An analysis of the fundamental nature of amplification and a description of the working principles of pneumatic, mechanical, carbon, vacuum-triode, magnetic and dielectric amplifiers

 

 

 

 

 

005
Prev

835
KB

4
Pgs

High-power Audio Amplifiers - Mannie Horowitz
As we increase the power output of an amplifier, we run into a whole new set of problems which are of importance to the designer and which must be solved properly and efficiently. Learn what these problems are and how they have been handled by one manufacturer.

 

 

 

 

 

010
Prev

366
KB

4
Pgs

Push-pull in Hi Fi - Mannie Horowitz
The push-pull amplifier has become standardized as the optimum circuit arrangement for providing adequate power output with a minimum of distortion -- so long as tubes are used under proper conditions. The author makes the performance of this type of amplifier thoroughly understandable.

 

 

 

 

 

015
Prev

696
KB

8
Pgs

Simplified Push-pull Theory - Julias Postal
Part 1: A graphical, non-mathematical explanation of how second-harmonic and other even-order distortion is reduced or canceled in push-pull stages, and a discussion of why push-pull operation has no effect on third- or other odd-order distortion products.
Part 2: Continuing the discussion of push-pull operation and why second-harmonic distortion reduced or canceled completely whereas third-harmonic distortion is not effected.

 

 

 

 

 

020
Prev

909
KB

6
Pgs

Push-pull A.F. Amplifiers - K. R. Sturley Ph. D.
Problems of the position of the composite load line and the construction of the valve load curves for classes A, B and C audio-frequency push-pull amplifiers are discussed and it is shown that B. J. Thompson's original work on class B amplifiers with matched valves can be extended to cover all classes of push-pull amplification under matched or unmatched conditions. Deductions regarding composite and valve-load curves as a result of voltage and current measurements are confirmed by photographs of valve-load curves obtained on the screen of a cathode-ray tube.

 

 

 

 

025
Prev

500
KB

5
Pgs

Circuit Features of High Fidelity Power Amplifiers - R. F. Scott
The first of several articles describing recent circuit developments designed to overcome effects of leakage reactance in output transformers; the basic McIntosh unity-coupled circuit.

 

 

 

 

 

030
Prev

410
KB

3
Pgs

Circuit Features in Hi-Fi Power Amplifiers - R. F. Scott
Circuit analysis of the single-ended, push-pull power amplifiers in National's "Horizon" series.

 

 

 

 

 

035
Prev

600
KB

3
Pgs

Why Do Amplifiers Sound Different? - N. H. Crowhurst
Reasons for performance differences in audio power amplifiers having similar published specifications.

 

 

 

 

 

040
Prev

648
KB

6
Pgs

High Power vs. Low Power Amplifiers - N. H. Crowhurst
An excellent article that should go a long way in settling the power argument for some time to come.

 

 

 

 

 

044
Prev

1.2
MB

6
Pgs.

Adequate Audio Power in the Home - James Moir
A discussion of the factors affecting the power required for satisfactory reproduction of typical program material and the methods of calculating it.
         

045
Prev

731
KB

3
Pgs

Audio Power Requirements and Statistics - C. Nicholas Pryor
A discussion of the power requirements of audio power amplifiers based on the statistical distribution of peaks in complex signals.

 

 

 

 

 

050
Prev

883
KB

4
Pgs

Energy Distribution in Music - John P. Overly
A knowledge of the manner in which the acoustic power encountered in music varies wrt frequency can be a useful tool in the design of components to be used in audio reinforcement or reproduction systems . . .

 

 

 

 

 

055
Prev

825
KB

6
Pgs

Audio Designer's Handbook, Parts 1 & 2 - Amperex Applications Engineering Laboratory, edited by David Saslaw
An up-to-date collection of amplifiers circuits and design information chosen as being representative of current and possibly future trends. Here in one collection will be found circuits which should fill practically ever need of the hobbyist.

 

 

 

 

 

060
Prev

630
KB

2
Pgs

Some Thoughts on Amplifier Design- A. Stewart Hegeman - Director of Engineering, Citation Kit Div., Harmon-Kardon, Inc.
Multiple feedback loops with up to 32dB of feedback with stability, extended frequency response and low impedance power supply are use in new hi-fi kit line. This article covers venerable, innovative and much respected H-K Citation II.

 

 

 

 

 
 

065
Prev

1.4
MB

15
Pgs

System Design Factors for Audio Power Amplifiers - M. V. Kiebert, Jr. - P. R. Mallory and Company
Prior to going into purely technical details, it appears to be desirable that an evaluation be made and some conclusions drawn as to why there should be . . . such disparity amoung the findings of the various A-B listening tests [ . . . ]


   

Section 2; Ultra-linear Amplifiers - 23 Articles

 
 

070
Prev

37 MB

214
Pgs

Download all the articles in Volume 1; Section 2
Collated into one bookmarked PDF.
 

 

 

 

 

 

071
Prev

2.0
MB

9
Pgs

Improvements In or Relating to Thermionic Valve Amplifying Circuits - Alan Dower Blumlein; assignor to Electric and Musical Industries Ltd, Great Britain
Blumlein's original patents are the basis upon which others subsequently developed what has been known since the mid-50s as the Ultra-linear circuit. Copy of both Blumlein's original 1938 UK patent and his subsequent, 1940, US patent is provided.

 

 

 

 

 

 

072
Prev

1.0
MB

4
Pgs

Basic Output Transformer; Pat. No. 2,680,218 - Herbert I. Keroes; assignor to Acro Products, Philadelphia, PA, USA. Applied October, 1950; granted June, 1954.
The present invention relates generally to push-pull audio transformers, and more particularly to systems of relatively arranging the windings of audio transformers to enable change of output impedance without change in performance.

 

 

 

 

 

 

073
Prev

2.0
MB

5
Pgs

Ultra-linear Amplifiers; Pat. No. 2,710,312 - David Hafler & Herbert I. Keroes; assignors to Acro Products, Philadelphia, PA, USA. Applied May, 1952; granted June, 1955
The present invention relates generally to amplifiers, and more particularly to amplifiers capable of wideband linear response, operable with substantially no distortion produced by harmonic response or intermodulation over a wide dynamic range, and with excellent efficiency. The amplifier of our invention finds particular application to audio power amplifiers, but may be applied with equal effect to a wide range of uses, and at supersonic and radio frequencies, as well as at audio frequencies.

 

 

 

 

 

 

074
Prev

900
KB

4
Pgs

Electrical System for Ultra-linear Amplifier; Pat. No. 2,791,646 - Herbert I. Keroes; assignor to Acro Products, Philadelphia, PA, USA. Applied October, 1955; granted May, 1957
The present invention is an improvement of that disclosed and claimed in United States Patent No. 2,710,312, issued to Keroes et al. That patent discloses an audio amplifier of the high fidelity type, which operates class B or class AB, i. e. in push-pull, and with a grid bias selected to assure that two push-pull connected tubes shall conduct in alternation. Applicants, in the above identified patent, disclose a system in which the amplifier tubes employed have screen grids, which are connected to relatively critical points of an output transformer, whereby to optimize simultaneously a number of operating characteristics of the amplifier. This operative condition is denominated "ultra-linear" operation, herein. Applicants also disclose that the screen grids may be driven from a tertiary winding of an output transformer. Screen grid drive by means of a tertiary winding may be essential! where the tube types employed require different DC voltages at the anodes and screen grids respectively.

 

 

 

 

 

 

075
Prev

870
KB

3
Pgs

An Ultra-linear Amplifier - David Hafler & Herbert I. Keroes; Acro Products, Philadelphia, PA, USA.
It has been claimed that there is no more room for improvement of power output stages since other elements of a complete sound system, particularly the electromechanical ones, are far inferior. There is a prevalent belief that, "One good amplifier is only marginally different from another." The proponents of this line of thought imply that significant improvement in power amplifiers is extremely difficult to achieve, an idea with which the authors agree but disagree as to the need for further improvement. Obviously, the weaker links do need improvement, but this is no reason to abandon the further development of the stronger links in the chain of audio reproduction i.e. the power amplifier primarily the power·output stage which is the prime generator of distortion in the purely electronic part of the audio system.

 

 

 

 

 

 

080
Prev

3.0
MB

18
Pgs

Ultra-linear Amplifiers, Parts 1 thru 3 - Fritz Langford-Smith & A. R. Chesterman
This first article gives a general introduction to the subject, with its history, some of its characteristics, and then an investigation into the effects of the tapping point on the power output and distortion. The effects of high resistive loads are also investigated.
The name has been the subject of much controversy. "Tapped Transformer" and "Triode-Tetrode" operation have been suggested in England, while "Partial Triode Operation" has been used in the Radiotron Designer's Handbook. None of these seem to have taken on, so that we are left with the title "Ultra-linear," which will be used throughout this article in its abbreviated form, "UL."
Part 2 includes the full issue of Radiotronics, June, 1955 which contains a germane article on "Square Wave Testing."
As well, Part two embodies later corrections to not only the text but to the placement of two graphs transposed in the original. Finally, there is an appendix outlining network theory in the, "Analysis of Two Generators Feeding a [Common] Load," which in the present case are the plate and screen of a pentode working with an "Ultra-linear" connection of the screen.

 

 

 

 

 

 

081
Prev

22
MB

80
Pgs.

Ultra-linear Amplifiers, Parts 1 thru 3 with the references cited throughout the document. - Fritz Langford-Smith & A. R. Chesterman
The references and appendices included are wide-ranging and much more conveniently presented with the document than as 16 separate PDFs.
         

 

085
Prev

630
KB

2
Pgs

Ultra-linear Amplifiers - Wireless Engineer Aug. 1955
In recent years, and particularly in the USA, the so-called ultra-linear amplifier has become popular among quality enthusiasts. A great deal has been written about it and a good many performance figures have been published which do seem to show some reduction of non-linearity distortion as compared with similar triode, tetrode or pentode amplifiers No serious attempt at explaining why this result should occur seems to have been made, however.

 

 

 

 

 

 

086
Prev

4.0
MB

52
Pgs

The Ultra-linear Power Amplifier An adventure between triode and pentode - Rudolf Moers
Introduction and history: David Hafler & Herbert Keroes (not the inventors) published their Ultra Linear story in 1951. Published in 1959, the Dutch book "Radio Technique - Part 1," written by A. J. Sietsma [then] of the Philips company . . . Sietsma made a homework exercise [of] screen grid negative feedback for students.

 

 

 

 

 

 

087
Prev

6.0
MB

107
Pgs

Basic Electron Tube Theory Expanded to Cover Optimized Ultra-linear Operation Using The Author's Optimised Electron Stream Applied Electron Tube Technology - Dennis Grimwood
The
website has been set up to assist people needing information for constructing or servicing transmitting, receiving, industrial, military, communications, audio, hi-fi, musical and test equipment applications.
The information presented therein is based upon a combination of the reported experiences of others, helpful guidance from my electronic guru friends, reference to published texts from people who are considered to be reliable technical experts, electron tube manufacturers' manuals, data sheets, catalogues and technical publications, and my own experiments, research and experiences over more than 50 years. Every concept presented on the site has been proven by practical application or test to work as claimed.

 

 

 

 

 

 

090
Prev

690
KB

3
Pgs

Tetrodes with Screen Feedback Further Light on the so-called "Ultra-linear" Circuit - Wireless World, Jan, 1956
After a period of caution, amounting in some quarters to undisguised skepticism, the "ultra-linear" output stage is undoubtedly here to stay. It was unfortunate, though, that Hafler and Keroes in popularizing this circuit for audio amplifiers should have chosen a term which, if it means anything. suggests that the transfer characteristic has been bent "beyond the straight" and is therefore still curved!

 

 

 

 

 

 

095
Prev

2.0
MB

5
Pgs

Amplifiers and Superlatives An Examination of American Claims for Improving Linearity and Efficiency - D. T. N. Williamson & P. J. Walker
The most commonly specified parameters of an amplifier are its harmonic distortion or intermodulation content, and these have tended to be regarded as the primary standard of "goodness." In 1944, one of the writers suggested that a standard of 0.1 per cent total harmonic distortion at maximum output was a good level of performance to aim at. Such a low distortion content is readily achievable by modern design methods and is, in fact, undetectable by listening tests, however refined. This arbitrary figure was chosen, not because it was the maximum permissible, but because, being rather lower than was absolutely necessary, a good margin is left for any deterioration of the equipment when in service.

 

 

 

 

 

 

100
Prev

560
KB

2
Pgs

Determining Screen Grid Dissipation in Ultra-linear Amplifiers - Leonard Kaplan
An important consideration in the design and adjustment of amplifiers using beam power tubes in screen grid feedback circuits "Ultra-linear" amplifiers is screen grid dissipation under maximum-signal conditions. In amplifiers of this type, [the screen grid] of each tube receives a fraction of the AC plate voltage of the tube, as well as a DC voltage, and contributes a portion of the power output. As shown [herein] the screen grid dissipation varies with the signal amplitude, and is always less than the product of the DC screen grid voltage and current. If this dissipation is less than the permissible screen grid input for the tube type used, it may be possible to obtain higher power output from the amplifier by an increase in the [B+] DC supply voltage, Ebb. If this dissipation exceeds the permissible screen grid input, it will be necessary either to reduce B+, or to increase the fraction of the AC plate voltage applied to [the screen grid] to [ensure its maximum] permissible input is not exceeded.

 

 

 

 

 

 

105
Prev

2.2
MB

3
Pgs.

Ultra-Linear Operation of the Williamson Amplifier - David Hafler and Herbert I. Keroes; Acro Products Co.
The Famous "Williamson" can be improved simply by replacing the output transformer and making a few minor changes in other components. The results are well worth the effort and expense.

 

 

 

 

 

 

115
Prev

1.7
MB

2
Pgs.

Designing an Ultra-Linear Amplifier - by Edward S. Miller
High-fidelity unit features low-distortion preamp and choice of speaker damping.

 

 

 

 

 

 

125
Prev

1.6
MB

3
Pgs.

High Quality Circuits - John K. Frieborn
Observations on ultra-linear, plus circuit features of three high-quality power amplifiers.

 

 

 

 

 

 

135
Prev

2.0
MB

4
Pgs.

Adapting the "Ultra-Linear Williamson to 6550 Operation - Herbert I. Keroes; Acro Products Co.
A new high-power output tube, the 6550, will find many applications in converting present-day amplifiers and in new equipment. Up to 100 watts push-pull can be had.

 

 

 

 

 

 

140
Prev

2.7
MB

5
Pgs.

A 50 Watt [Ultra-linear] Power Amplifier - David Hafler, Dyna Company
A well engineered high power amplifier providing high fidelity performance and suitability for home construction.

 

 

 

 

 

 

145
Prev

1.8
MB

3
Pgs.

120 Watts of Hi-Fi Power - David Hafler; Dynaco, Inc.
Construction of an amplifier with IM as low as .15% at full power, but be careful of your speakers with this one.

 

 

 

 

 

 

150
Prev

1.7
MB

4
Pgs.

Ultra-Linear Operation of 6V6 Tube - David Hafler; Acro Products Co.
One of the best designs in recent years covering an audio amplifier using 6V6 tubes. The author, in this case, has converted a Grommes unit to illustrate his design idea.

 

 

 

 

 

 

155
Prev

1.3
MB

2
Pgs.

25 Watt [Ultra-linear] Power Amplifier - Norman Kramer; Project Engineer, Allied Radio Corp.
Circuit details on a new linear amplifier kit which uses two 5881 beam power tubes and a special output transformer.

 

 

 

 

 

 

160
Prev

1.7
MB

4
Pgs.

A 60 Watt UL Amplifier
Construction details on a commercially designed, high-power amplifier for the serious audiophile. It uses four KT66s.

 

 

 

 

 

 

165
Prev

1.2
MB

2
Pgs.

The Ultra-linear II Power Amplifier - Herbert I. Keroes, Acro Products Co.
A new 60-watt power amplifier kit that employs an unusual feedback circuit with exceptional stability. This article contains a link on the PEARL site to an article on Keroes' "hybrid feedback" that is particularly interesting. He mentions filing for a patent but a search of Google patents fails to pull a hit.

 

 

 

 

 

 

170
Prev

3.0
MB

4
Pgs.

40 or 60 Watt Hi-Fi Amplifier [Ultra-linear] with Tertiary [Cathode] Feedback - Thomas F. Burroughs
Complete construction details on a stable, high-power audio amplifier with additional negative voltage feedback derived from a tertiary winding to which the cathodes of the output tubes are directly connected. See "Amplifiers and Superlatives" above.


 

 

Section 3; The McIntosh Unity-coupled Power Amplifier - 15 Articles

 


 

No
Prev

61
MB

129
Pgs.

Download all the articles in Volume 1; Section 3
Collated into one bookmarked PDF.