top of page

​​​​Introducing Our Groundbreaking Calibration Tape

 

Measuring the variables of magnetic fields has always been one of the most challenging aspects of analog recording.

At ANKO Lab, we have developed an original methodology rooted in the theoretical principles of magnetic flux measurement on carriers. This approach is built on foundational research—including the pioneering work of Jay McKnight—that continues to guide advancements in the field.

 

We use proprietary measuring instruments designed from the original AMPEX methodology, now enhanced with cutting-edge tools such as Audio Precision analyzers—technology that AMPEX engineers of the 1960s could only dream of. This powerful combination ensures exceptional precision in every measurement.

 

Our process integrates theoretical modeling, hands-on testing, and modern software that simulates the behavior of electronic circuits. For recording and quality control, we rely on specialized mono magnetic heads manufactured by FluxMagnetics, ensuring absolute reliability and consistency.

 

These combined efforts deliver the highest possible accuracy in capturing key magnetic flux characteristics—flux level, azimuth, and equalization—on tape, fully compliant with IEC 94-2 international standards.

 

Each calibration tape is:

  • Individually processed

  • Assigned a unique serial number

  • Verified with test data securely stored in our database

 

The result is a universal calibration tape suitable for aligning any brand of reel-to-reel tape recorder.

If you have questions or need assistance in aligning your machine for optimal performance, our team is ready to help.​​

MSRP (1/4"):

​7.5 ips - $175.00

15 ips - $175.00

30 ips - $190.00

Double Speed - $253.00

​​

MSRP (1/2"):

​7.5 ips - $322.00

15 ips - $322.00

30 ips (AES) - $368.00

Double Speed - $448.00

​​

1k, 10k, 16k, 50Hz, 100Hz  

IEC / CCIR / NAB / AES

Available upon request: any flux level, optional test tones, and sweep tones.

​*Shipping and Taxes Not Included

​

​

Boxes_edited_edited.png

Simplified Alignment Procedure >

Scroll down for Q & A's

What is the difference?

There are numerous sources of alignment tapes available on the market.

​

Based on our experience and feedback from customers/studios around the world, there are no trustworthy reliable sources that can be used as a reference etalon.

​

We have tested over 30 pcs of alignment tapes - in the past 15 years of production we've seen every tape has an azimuth differ substantially (some even up to +/- 60 deg!), the flux level dropped by 25%, tones level unstable.

 

No wonder why some users complaining about a quality of recorded tapes, just because of a "tape producer" trust to whatever alignment tape and had no idea that levels are off, and some users never even bother to align their machines (but that's another subject).

 

There is the International Electrotechnical Commission (IEC) Standard 94, "Magnetic Tape Sound Recording and Reproducing Systems" with parts 2 "CALIBRATION TAPES":

 

- "Tape for making adjustment and comparative assessments of the reproducing performance of both professional and domestic magnetic tape recording/reproducing equipment."

 

- "Each standard calibration tape shall have at least the following sections:

1) reference [fluxivity], 2) azimuth, and 3) amplitude/frequency response."

 

For instance, for speed 15 ips, requirements for the alignment tape: 

​

- Reference flux level (nWb/m), tolerance +/-5%

​

- Signal at reference frequency (1kHz), distortion up to 1%

​​

- Level fluctuation up to 10kHz - <0.5dB; over 10kHz - < 1dB

​

- Recording angle of 90 deg +/-1` (Azimuth about 0 deg)

​

We have developed a process of measuring and recording to meet all required by standard (see above) conditions.

 

An original methodology based on theories of measuring variable magnetic flux level, tone signals level and azimuth.

 

Utilizing our proprietary measuring instruments, developed based on the methodology at AMPEX, alongside cutting-edge measurement devices (deviation = 0.01% of frequencies and magnetic flux level) we ensure the utmost precision.

 

To ensure recording and quality control, we employ special full-size heads developed by FluxMagnetics.

 

All these efforts culminate in achieving maximum accuracy of magnetic flux (including flux level, azimuth, and equalization) recorded onto magnetic tape, fully compliant with the requirements of the international standard IEC 94-2.

 

As an audiophile guy I can really hear a benefit of the correct azimuth alignment - precise calibration would give you a pleasure of better sound stage, details, space.

 

Next topic we can do about a fringing effect (low frequencies playback abnormal effect). That will be an interesting subject.

 

Please contact ATR Service anytime if questions.

What is the fringing effect?

What type of tape we use?

What is the equipment setup for recording magnetic flux on calibration tape?

  • Link to Journal of the Audio Engineering Society (Jay McKnight paper)

  • Pages from Ampex ATR manual

The RTM SM911 tape

An amplifier has been developed and manufactured to work with the magnetic flux loop. It is calibrated with an accuracy of 0.01dB to perform frequency correction at various tape playback speeds. The actual frequency response of the amplifier fully matches the calculated and simulated responses. The reference model for comparison of correction is an R+C circuit.

​

  1. By using the magnetic flux loop and amplifier, we have achieved the ability to adjust the playback amplifier circuit with an absolutely flat/linear frequency characteristic with constant times corresponding to selected speeds and standards.

  2. For measuring the level of magnetic flux, a special reference measuring head was manufactured (by FluxMagnetics) and a high precision integrating amplifier was used.

  3. Knowing the characteristics of the measuring head and the parameters of the integrating amplifier at a frequency of 1 kHz, the level of recorded magnetic flux is calculated with sufficient accuracy (measurement error does not exceed 1% or 0.1 dB).

  4. Based on the obtained values, signal recording level correction is performed.

ATR Service, Inc.

7322 138th Ave

Newcastle, WA, USA
+1.717.852.7700

bottom of page