Transformers Comparisons and New Applications

After Hashimoto Electric introduced a new series of tube transformers with its own brand name, a few well known hi-fi contributors were impressed with these products and published articles on leading hi-fi magazines in Japan.  With permission from one of these authors and publishing companies, the essence of these articles are summarized in this section.     

One of those authors is Mr. Tadaatsu Atarashi who was a Vice President of Marketing with Philips Classics Productions, and has been a regular contributor to specialized hi-fi magazines for some years.  It’s well known that his designing philosophy is to build amplifiers that could yield the sound that is closest to the real music.  This makes sense because he was in an environment to appreciate professional performances through his profession.  His well-known definition of amplifier is, “An amplifier is nothing but a tool to listen to music.”  In this sense, he could appreciate amplifier parts more than anybody else because he treats parts as if they were building blocks of music.

In recent years, Mr. Atarashi has been very impressed with the sound that Hashimoto transformers could yield through his various amplifier projects.  In 2003 and 2004, he conducted two transformer comparison projects that were featured on the "Tube Kingdom" which is a quarterly publication from the "Stereo Sound" (the "Stereo Sound" has been one of the leading hi-fi magazines for decades in Japan).  Mr. Atarashi also featured several individual tube amplifiers that utilize Hashimoto transformers on the “hi-fi Audio – Radio Technology” that is a monthly publication in Japan.

As you can see in the detailed sections, some of designs are somewhat different from ours.  However, it’s interesting to see how Mr. Atarashi or Japanese contributors have been experimenting different circuits for the purpose of obtaining the most realistic sound.  On the other hand, some circuits are very traditional, and any of these circuits help us to realize how Hashimoto transformers could be utilized to pursuit the best sound possible.

High Power Push-Pull Applications and Transformers Evaluation                               

1.   EL34 Push-Pull Monaural Power Amplifier (Article Summary, Photos, Schematic) - This amplifier was originally featured on the January 2003 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi.  Mr. Atarashi is a monthly regular contributor to this magazine, and this particular amplifier appears to have become a base model that was used on the "Push-Pull Transformers Comparison"  featured on the "Tube Kingdom" Winter 2003 Issue.  

2.  Push-Pull Transformers Comparison (Article Summary, Photos, Schematic) - The Summary of an article testing high power Push-Pull transformers.  This article was originally featured on the "Tube Kingdom" Winter 2003 Issue.

3.  KT-88 UL Push-Pull Monaural Power Amplifier (Article Summary, Photos, Schematic)  - This amplifier was originally featured on the October 2004 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi.

Non-NFB Push-Pull Applications

1. EL34 Non-NFB Push-Pull Triode Connection Power Amplifier - Project #1 (Article Summary, Photos, Schematic) - This amplifier was originally featured on the February 2003 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi.

2. EL34 Non-NFB Push-Pull Triode Connection Power Amplifier - Project #2 (Article Summary, Photos, Schematic) - This amplifier was originally featured on the March 2003 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi. 

Miniature Tube Push-Pull Applications

1. EL84 Push-Pull Stereo Power Amplifier (Article Summary, Photos, Schematic) - This amplifier was originally featured on the October 2003 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi. 

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Single Ended Applications and Transformers Evaluation

1.  PL83 (6BQ5 equivalent) UL Single-Ended Stereo Power Amplifier (Article Summary, Photos, Schematic) - This article was originally featured on the February 2004 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi.  Mr. Atarashi is a monthly regular contributor to this magazine, and this particular amplifier appears to have become one of the base models that were used on the "Single-Ended Transformers Comparison"  featured on the "Tube Kingdom" Spring 2004 Issue.

2.  Single-Ended Transformers Comparison (Article Summary, Photos, Schematic) - an article testing single-ended transformers on a PL83 and 300B power transformers.  This article was originally featured on the "Tube Kingdom" Spring 2004 Issue.

3.  This is my current project, 12BH7 Cathode Follower Driven 300B Single-Ended Power Amplifier - currently only photos are uploaded, but I will describe this project in details very soon.

Miniature Tube Single-Ended Applications

1. 6AQ5W/6005 UL Single-Ended 4Ch Power Amplifier (Article Summary, Photos, Schematic) - This amplifier was originally featured on the January 2004 Issue of the "High-Fidelity Audio: Radio Technology" by Mr. Tadaatsu Atarashi.

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Last changed: 02/01/15