Opinions on Flux Magnetics quarter track heads

TommyTunes

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Jan 16, 2012
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I'm sending my Otari head stock to JF Magnetics to have a half track Flux Magnetics playback head installed and I'm on the frence if I should also replace the quarter track head. I'm waiting on a Tube Repro preamp and have about 60 7 1/2 prerecorded tapes that I've been buying mostly Jazz and Rock. Do you think the Flux head would be a benefit for quarter track?
 

Bruce B

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Anything will be a benefit to quarter track. You can guarantee that the Flux heads will be the best available!
 

jdza

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May 3, 2010
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The FM 1/4 track heads can deliver astonishing results on appropriate tapes. I use a Studer A 80 with FM heads and also have a Revox G36 as an alternative ( Revox PR 99 too ,but that runs a very distant 3rd). Despite the lovely tone of the G 36 the FM head on the A80 is simply in another class.

However ,I have not had good results with the Studer/FM heads with the Bottlehead electronics. I am not sure if the heads for the Otari have similar electrical characteristics.I have had excellent results with the 1/4 track (and 1/2 track) Nortronics Pro heads with BH .
 

Bruce B

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The FMER heads works perfectly with the Doshi Audio tape pre. The head inductance is ~225. I know they didn't work the best with the deHavilland Model 222 either.
 

Ron Resnick

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The FM 1/4 track heads can deliver astonishing results on appropriate tapes. I use a Studer A 80 with FM heads and also have a Revox G36 as an alternative ( Revox PR 99 too ,but that runs a very distant 3rd). Despite the lovely tone of the G 36 the FM head on the A80 is simply in another class.

However ,I have not had good results with the Studer/FM heads with the Bottlehead electronics. I am not sure if the heads for the Otari have similar electrical characteristics.I have had excellent results with the 1/4 track (and 1/2 track) Nortronics Pro heads with BH .

Where you ever able to compare directly a machine with stock Studer heads versus a machine with Flux Magnetics ER heads?
 

jdza

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May 3, 2010
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Where you ever able to compare directly a machine with stock Studer heads versus a machine with Flux Magnetics ER heads?

Not on identical machines with 1/4 track heads .

On 1/2 track heads I have identical A80s with FM and Studer heads but conventional vs Butterfly,different head specs and different replay electronics. All I can say is that a ML5 with the correct spec Studer Butterfly heads vastly outperforms an A 80 R/RC with FM heads and Studer electronics,even with updated caps etc. That is in my system and my ears and my ML5 cards are much modified.

The A 80 R with FM heads do measure astonishingly flat. I once ran a 7.5 ips MRL tape at 15 ips by accident and saw flat output way beyond expected.
 

Ron Resnick

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So it seems like you would be of the view that if stock Studer heads are not overly worn out, there is no reason to just automatically replace stock Studer heads with Flux Magnetics ER heads?
 

Ron Resnick

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Is your ML5 providing all of the pre-amplification of the signal coming off the playback head, or are you using a first stage pre-preamplifier in the headlock itself?
 

stellavox

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Apr 23, 2010
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Maybe 8 years ago I took an opportunity to "compare" 2track heads from FM, Bogen, 9000series Pro Nortronics and Nagra. FM, Bogen and Nortronics were all very close.

From other comparisons can say that the Ampex heads are all quite good. Do suggest replacing ANY Japanese head however.

Charles
 

jdza

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May 3, 2010
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Is your ML5 providing all of the pre-amplification of the signal coming off the playback head, or are you using a first stage pre-preamplifier in the headlock itself?

The ML5 used the Studer A80RC architecture exclusively. AFAIK no A80 used headblock based amplification. That feature was introduced on the later A810 and A820 models. The Cello electronics was designed for use with the A820,though not exclusively so as other brands of transport could supposedly also be accommodated. Not sure what Cello did with the headblock amp but it was never a feature in the ML5.
 

microstrip

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The ML5 used the Studer A80RC architecture exclusively. AFAIK no A80 used headblock based amplification. That feature was introduced on the later A810 and A820 models. The Cello electronics was designed for use with the A820,though not exclusively so as other brands of transport could supposedly also be accommodated. Not sure what Cello did with the headblock amp but it was never a feature in the ML5.

Everything you always wanted to know about the ML5A: http://www.geocities.jp/dave_group_japan/ekoukoku15.html.

ML-5 Master Recorder


The most important design goal of all Mark Levinson Audio Systems products is, in a word, accuracy. Electrical signals must be faithfully reproduced, with an absolute minimum of distortions and colorations of any type which cause the output signal to differ from the input signal. Though sophisticated instrumentation provides invaluable information regarding the electrical accuracy of each design, comprehensive listening evaluations are essential to confirm the sonic validity of a component.

As our products progressed technologically, it became increasingly difficult to sonically evaluate their accuracy using conventional source materials. It is a known fact that most conventional source materials, such as records and tapes, undergo excessive signal processing, frequently resulting in limited dynamic range as well as alterations in the timbre of recorded instruments and voices. Furthermore, because we were not present at each recording session, it was impossible to determine how accurate or inaccurate the source material was. We quickly realized the need to produce our own master tapes, but found that even the finest available tape machines lacked the necessary quality of reproduction. We therefore developed the ML-5 master recorder by combining one of the finest professional transports available with audio circuitry of our own design. This machine performed so well that limiting and noise reduction measures were unnecessary and, when used with a simple two microphone recording system of equal quality, yielded master tapes of known superior accuracy which could be used for valid sonic evaluation of our products.

Although the ML-5 and the master tapes made from it were initially designed for our own use, many of our representatives, as well as other audio manufacturers, became aware of their potential as a demonstration and research tool. High-quality record companies, free-lance recording firms, and several dedicated musicians have since discovered the outstanding recording and reproducing capabilities of the ML-5, surpassed in realism only by the original musical event. The quickly gained acclaim and enthusiasm for the ML-5 prompted its inclusion in our product line.

The transport of the ML-5 is the A80RC made by Studer of Switzerland. Studer professional tape machines are extensively used in prestigious recording and broadcast studios worldwide and are recognized as the "standard of the industry" with regard to multi-track and mastering tape machines. The heart of the A80RC is a massive die cast chassis which is precision machined to close tolerances to permit exacting and repeatable alignment and location of motors, head assembly and other associated components in the tape path. This type of construction yields stability and strength and therefore rarely requires alignment. Sophisticated logic circuitry, located on eight plug-in printed circuit boards at the front of the machine, control all transport functions. Several LEDs act to identify a malfunctioning circuit board, in the unlikely event that service is needed. Therefore, the machine is largely user serviceable. This modular concept also applies to all other mechanical aspects of the machine, permitting quick and convenient conversion of quarter inch tape format to other formats with the appropriate conversion kit. For maximum reliability in professional recording situations, the A80RC has been designed for long-term, continuous-duty use.

A80RC head assemblies are made to very precise tolerances. Low gap splatter introduces less phase errors than many other head assemblies. The headblock features wide-track (butterfly) record and playback heads. This is the European standard system which provides better signal to noise ratio, improved stability and greater freedom from drop-outs. This headblock also incorporates a full-track erase head which permits complete erasure of any pre-recorded information.

These superb electromechanical characteristics of the StuderA80RC offer the high level of performance and quality required to best utilize our interfacing audio electronics and make this transport the ideal choice for the ML-5 master recorder.

The audio electronics of the ML-5, designed and developed by Mark Levinson Audio Systems, fit directly into the existing card cage of the Studer A80RC transport. These electronics consist of five printed circuit boards: two reproduce, two record and one power supply regulator.The audio circuitry is completely discrete, utilizing carefully sorted and matched transistors, precision 1 % metal film resistors and high-quality precision capacitors. The voltage gain stages of this audio circuitry are differential amplifiers employing cascoding techniques for optimal linearity and improved common mode rejection range. Precision current sources further improve common mode and rail modulation rejection. All circuitry operates in the Class A mode for further refinement. Circuitry of this type makes possible the use of only small amounts of negative feedback, thus eliminating potential sonic degradation due to transient distortion while maintaining superb DC stability. This circuitry features topology very similar to that which is used in Mark Levinson@ preamplifiers.
A precision voltage regulator, very similar in design to our PLS series of power supplies, provides DC voltage for the audio circuitry. Receiving unregulated voltage from the power transformer in the A80RC, this regulator is capable of maintaining load regulation of 0.05% and has a wideband noise output of 50 µV (-86 dBV). This ensures absolutely constant DC voltages under all operating conditions and that no additional noise due to the power supply will be added to the circuitry.

Each playback card provides separate alignment trimpots controlling low frequency equalization, high frequency equalization and output level. These controls allow optimal and convenient alignment for each of the two available speeds. A toggle switch, mounted to the circuit board, permits the selection of the NAB or CCIR equalization standard for 15 ips operation. Each record card features separate trimpots for high and low speed adjustment of output level, bias and high frequency equalization. A head compensation trimpot is also provided to adjust the electronics for individual head characteristics. This permits consistently optimal alignment of the record electronics to any Studer headblock assembly. A toggle switch, mounted to the circuit board, permits the selection of the NAB or CCIR equalization standard for 15 ips operation.

The operating level of the ML-5 is defined as 200 nanowebers per meter equals -6 dBm (387 mV). At operating level, a typica130/15 ips ML-5 yields record/play frequency response of -h 1.5 dB, 31.5 Hz to 125 Hz and + 0.2 dB, -0.5 dB, 125 Hz to 20 kHz. At 14 dB above operating level ( + 8 dBm) total third harmonic distortion of an ML-5 is no more than 1.8% at 400 Hz, both speeds. The ML-5 yields typical signal to noise ratios of better than -54 dB referenced to the operating level and an ASA "A" weighted noise figure of-62 dB referenced to the operating level, both speeds (without noise reduction). Wow and flutter of an ML-5 is better than.04% peak weighted.
The ML-5 produces startlingly realistic, low-noise and distortion-free recordings, it is capable of effortlessly reproducing the wide dynamic range presented by live musical recording. The sonic quality of the ML-5 defies description and really must be experienced firsthand to be appreciated. The A80RC features a digital counter which reads real time (minutes and seconds) accurately. This real time counter operates in record, play, rewind and forward wind. A tape may be timed in any of these modes. At the end of a tape the counter automatically stops.

The A80RC includes a special feature called "return to zero". The "zero" button may be pressed at any time and the counter will read zero hours, minutes and seconds. The machine may then be operated in any mode and, when the "LOC" (locate) button is pressed, the transport will return to the portion of tape where the "zero" button was pressed. This feature can be used, for example, to return to a critical passage or place of interest on the tape. It is also very useful when making demonstrations or comparisons of equipment.
The tape transport functions, real time counter and "return to zero" features can all be operated by remote control. The A80RC also contains special circuitry which enables the machine to be controlled by a computer. This feature can be of great importance to some users.

The A80RC includes features to facilitate editing and splicing of tape. An "edit" button, when engaged, brings the tape up to the play head for monitoring while the reels are turned manually. While in the "edit" mode, activation of the edit control will bring the tape away from the heads and allow variable speed forward and reverse tape motion. The tape is returned to the heads when this control is once again centrally located. Precise edit and splicing points may, therefore, be conveniently located on the tape. A marking pencil, scissors and tape splicing guide have been built directly into the headblock assembly, complementing the edit function.
Each ML-5 is fitted and wired with an engraved back panel containing Camac connectors for input and output connections. The XLR connectors may be reconnected at the customer's request. This back panel also contains two four-pm connectors that are self-locking and have gold-plated contacts. The power supply connector makes available ± 15 VDC to power auxiliary circuitry, if desired. With the regulator circuit board removed from the card cage, an external -±-15 V power supply, such as the PLS-151, may be used to power the audio circuitry via this connector. An optional meter drive circuit is available allowing a convenient means to interface the ML-5 to a metering panel (not available from Mark Levinson Audio Systems) via the second four-pin connector. Separate alignment trimpots are located on each record and play circuit board for precise meter calibration.

The ML-5 master recorder is available in either a 30/15 ips or 15/7.5 ips configuration. 30 ips operation is equalized to the AES standard while 15 ips equalization is switchable for both the NAB and CCIR standard. 7.5 ips equalization is factory set to either the NAB or CCIR standard at the customer's request. Each ML-5 is shipped only after exhaustive testing by factory technicians. All electrical testing and alignments are done with the aid of state of the art test equipment and must meet exacting standards. The playback electronics are adjusted with the Magnetic Reference Laboratory alignment tapes. The record electronics are then aligned for optimal performance with Ampex 456 tape. Further, the transport is carefully checked and adjusted if necessary, to ensure precise electromechanical operation.
Those persons already owning a Studer A80RC recorder may either ship their machine, or headstack and oscillator, to the factory for the ML-5 modification procedure, or purchase a modification kit and install it themselves.

The technical specifications that are included here, although representative of certain merits, are not sufficient to determine overall sonic accuracy. We suggest that your decision regarding the purchase of this product be based upon your personal evaluation and examination, and the recommendations of your Mark Levinson representative.


Relevant Data
Input Impedance: l5 kilohms or greater Recommended Load:10 kilohms or greater AC mains voltage: User selectable for 100-120 or 220-240 VAC Net Weight:1171bs.
Shipping Weight:1611bs.
Maximum Overall Dimensions (excluding stand):
11 1/4" H, 25 1/8"H W, 21 5/8" D Detailed dimensions of the ML-5 and stand are available from vour Mark Levinson representative.

Research and development, and the evolution of new technology, can give rise to the need for change. We reserve the right to incorporate changes in this product without notice.

Mark Levinson Audio Systems, Ltd. 'Post Office Box 701
Middletown, Connecticut 06457 USA




 

andromedaaudio

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But from what i Read hear posted by stellavox its only 3 cards change from a stock.
Good freq response numbers better then stock
 

stellavox

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Apr 23, 2010
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I remember hearing or reading that ML originally wanted to use the Stellavox TD88 as the basis of his ML5 but the 88 proved unreliable so he switched to the Studer A80. The 88 was "super ceded" by the TD9.

I had the 5 cards for the ML5 plus some spares. The cards were two repro electronics (one per channel) two record (one per channel) and a power supply card. The repro card used a potted module very similar to the phono card in the ML1 while the record card used another module with less gain. The audio circuitry in the Cello 603 module was updated somewhat while the power supply was very much upgraded - especially with the last ASR-3 revision

Charles
 

andromedaaudio

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I like the modular idea , would be nice if other manufacturers would step in and make some cards for an A 80 like boulder .
And another high end manufacturer concentrate on the drive system and voila there is the reference tape deck .
Apart from for example doshi /tapeproject and some others i forgot to mention there seem to be little interest in designing something new by large industry players , extracting the last bit from 60 billion others seems more interesting , lol .
 

microstrip

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I remember hearing or reading that ML originally wanted to use the Stellavox TD88 as the basis of his ML5 but the 88 proved unreliable so he switched to the Studer A80. The 88 was "super ceded" by the TD9.

I had the 5 cards for the ML5 plus some spares. The cards were two repro electronics (one per channel) two record (one per channel) and a power supply card. The repro card used a potted module very similar to the phono card in the ML1 while the record card used another module with less gain. The audio circuitry in the Cello 603 module was updated somewhat while the power supply was very much upgraded - especially with the last ASR-3 revision

Charles

Several known professionals were using the Cello Audio Suite with P603 directly wired to tape heads in the 90's, as reported in the "Cello Professional Equipment" leaflet. https://www.matthew-james.net/Customer-Content/WWW/CMS/files/Cello-Prof-Audio-Equip_v3.pdf.pdf Does anyone know if they are still using them?
 

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