Is it all in your head?

Greetings, everyone. :-)

I was perplexed by how AIWA presented their heads. I frequently came across definitions such as "Amorphous Head," "HX Head," "Narrow Gap Head," and so forth. Therefore, I've decided to resolve this technical puzzle and share the answers with anyone who might be interested because it's very confusing.

The World of Personal Stereo Hi-End Heads

Tape heads are the main sound element in every tape deck or portable stereo. The head has to have the capability of reproducing a wide range of frequency responses in the sound spectrum. It is then up to the amplifier to translate and replicate the sound quality. A high-quality head needs to be durable enough to last a long lifespan of use.

As long as you used high-quality tapes, good ferrite heads used to last a very long time. For instance, low-quality ferric oxide tapes are one of the most likely types to do damage to your head. Unlike most other head materials, ferrite is a ceramic material that has a high permeability, but it is comparable to the majority of other head materials. 

AKAI had special ferrite heads. They called these "glass" and "crystal" ferrite heads. Meaning, the housing of these heads was made out of glass, but they had ferrite cores laminated into them, making them highly durable.

AKAI's Super GX Head: Crystal & Glass Ferrite head

Permalloy heads, on the other hand, were extremely soft and would develop grooves pretty quickly. Plain Permalloy heads were almost always found on the majority of low-end decks. Permalloy is an alloy that consists of roughly 79% nickel and 21% iron.

Kenwood CP-G5 Standard Permalloy Head

Some decks, such as those made by Nakamichi with the "Crystal Permalloy" heads, were hard and lasted extremely well.

Nakamichi Dragon: Crystal Permalloy Head—hard combination

While most manufacturers used either Permalloy heads or some proprietary variation of them. Although they wear down rather quickly, these heads are easily resurfaced.

Aiwa's DX Head: Combination of Permalloy & Epoxy 

Sendust heads lasted significantly longer than average, were harder than most Permalloy heads, and had excellent magnetic performance. Sendust is a metallic alloy with high permeability composed of a certain proportion of silicon, aluminum, and iron.

Pioneer CT-F800 Sendust Head (notice the grooves on the head surface)

In the 1980s, the newest technology was amorphous heads, which are meant to last longer and wear more slowly than other types of heads. Additionally, compared to other head types, they have a wider dynamic range and clearer highs. Amorphous heads became the new standard for many head manufacturers.

Generally speaking, amorphous heads last far longer than Sendust heads, which is significantly longer than any Permalloy. It is also believed that amorphous materials are harder than crystalline ones of the same composition. Laser amorphous heads were precisely cut to improve surface contact with the tapes. Cutting an amorphous material precisely and accurately is very difficult without a laser.

A notable exception to the amorphous rule are the well-known AKAI GX heads, which were created using a combination of Glass and X'tal, hence the GX name. According to AKAI, they should last just about forever, and they don't groove like straight ferrite and permalloy heads. As a result, AKAI offered a 15-year warranty solely for the head.

Akai's GX Head: Crystal & Glass head illustration

AIWA's Golden Years

Following Panasonic's AX Amorphous Head RX-S40, RX-S41, and RX-S45 (1984) and the FG Amorphous Head (1989), and following Sony's WM-D6C (1984) and WM-DC2 (1985). AIWA, the market leader in personal headphones, introduced their first Amorphous Head in March 1989. 

Panasonic's RX-S40; AX Amorphous Head

Aiwa's Hi-End Heads come in three different versions and are exclusive to IC Logic Control units.

1. Amorphous Head.

2. Narrow Gap Head.

3. HX Head—Hyper eXtended Bass Head.

Amorphous Head: "PX303A (PX30, PX900) features an amorphous head, often found only in audiophile cassette decks, for a remarkable improvement in playback fidelity. Amorphous alloy displays exceptionally high maximum magnetic flux density, outstanding signal linearity, and minimal noise generation. Add to this a remarkable hardness for extra durability, and you have one of the finest heads available." (From Aiwa's catalog, 1989)

HX Head: "The HX head featured in the HS-PL303A uses a slightly peaked contact surface to achieve greater signal linearity, particularly in low bass frequencies, for clearer, more accurate signal reproduction." (From Aiwa's catalog, 1989)

The first AIWA portable stereo to have the triple-feature combination head, Amorphous-HX-Narrow Gap Head, was the iconic HS-PX303. Later, Amorphous Heads were just plain Amorphous or a combination of Amorphous & HX heads. The last one, a narrow gap head, was created by AIWA and improved upon from V1.0.

    AIWA's PX303 Amorphous-HX-Narrow Gap Head

Later on, AIWA produced various head combinations in specific models, such as

• Amorphous Head is found only on JX707, RX70, and PX1000.
• Narrow Gap Head found on the PX20, JX505, JL505, PX303, PL303, PL55 (V1.0), and TP38.
• Combo: Amorphous—HX Heads Found on JX3000, JX2000, PX303, PX505, PL50, RL50, and RX50.
• HX Head was found only on PL303, WR707, PL777, PL707, P705, and P505MkII.

Aiwa HS-PL70/HS-PL707 - Hard permalloy HX

AIWA Introduces their Bi-Azimuth Head Alignment System

In 1987, Sanyo introduced the first bi-azimuth, which they named "Double Azimuth." As with their JJ series, it was the first method of designing double-point pins azimuth. (Series 4, 5, 6, and beyond).

Sanyo JJ-P100 Bi-Azimuth Head System

Sanyo quoted, "In addition to the small, light, good pursuit of high sound quality. High fidelity plays with a double azimuth head. The playback head adopts a double azimuth head, which reproduces the sound recorded on the tape faithfully. For the headphone stereo, it is a small, high-performance mechanism. We also pursued a total dynamic quality, such as extending the playback ability of the low range using aluminum for the voice coil." (Automatic translation from Sanyo's Japanese Catalog 1988)

Aiwa's own simple concept of Bi-azimuth Head Alignment was promoted and described as follows: "This new feature automatically compensates for head alignment inaccuracies, which are common to auto-reverse tape drive systems with fixed heads. When the tape reverses direction, its position shifts slightly, causing a shift in azimuth, the relative angle of the tape to the head. In either tape direction, absolutely precise azimuth alignment is essential for optimum response, particularly in the high frequencies. To assure this, the Bi-azimuth Head Alignment automatically adjusts the head to the proper position relative to the tape in each direction. Bi-azimuth head alignment is found on selected higher-priced models." (From Aiwa catalog 1989)

AIWA's HS-PX30 with the Bi-Azimuth Head mechanism

An illustration of the Aiwa concept of bi-azimuth

Bi-azimuth is only found in the JX303, JX30, JL30, RX30, TX303, RL30, PL303, PX303, JL50, JL505, F50, and TP38 models. Additionally, it is present on early JX505, JX50, EX50, EX500, and JX2000 models that have the previous AIWA logo; Bi-Azimuth is no longer used in the new logo versions for JX2000 and JX505 models. See the attached photos.

Left: AIWA HS-JX2000 new logo without Bi-Azimuth. Right: JX2000 old logo with Bi-Azimuth.

Sony also attempted a different approach and invented the world's first portable stereo with a double-head design, the WM-EX909/FX909 (1992). It was an expensive approach, but everyone else was left far behind with their plastic-mounted heads and a poor, degrading sound.

Sony's WM-EX909 Dual Head Concept

Despite being the "inventor" of the Walkman, Sony lagged behind AIWA in a number of areas. By purchasing AIWA in 1992, Sony attempted to make up for that, which ultimately led to the demise of the greatest personal stereo leader. Sony Walkmans, however, will undoubtedly be remembered as the decade's most popular brand; this is still the company's biggest advantage to this day.

Be Good :-)

TheLion

This article was first published on the old Stereo2Go Forum, June 2011

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