master tape sound lab

sonic upstream



For Orders: email at

1.High Quality Master Tape Dubs: limited releases, various formats

MTSL offers high quality 1 generation master tape dubs. Currently our catalogue contains 55 titles of diverse music, from jazz to classic and other genres, all of which were recorded onto/from 1st generation master tape with strictest quality standards.

The MTSL master tape dubs are recorded directly from the original master tapes, as MTSL owns those originals, and have a license to release them in limited numbers (100 per title).

The original analog master tapes, from which we do one-by-one real time customized transfers on top notch heavily modified Studer A80 machines, were created by the well known recording engineer and audiophile, Kostas Metaxas using a dedicated direct-onto tape technique and state-of-the-art all analogue gear, including a modified Stellavox SM8 master recorder fed directly by a pair of microphones, without using any sound overdubbing, processing and/or other signal alterations. This recording process, similar to the Direct Metal Mastering of  LPs, was applied in very few cases in the analog recording practice and offers outstandingly transparent sonic performance. For further detail on the recording process, please see “The Art of Recording”

Available formats and pricing, for each 30 minutes of Master Tape Record

(CCIR, NAB also available):


5.1 Live and studio recordings on analog master tape recorders.

5.2 Master tape restorations and transfers.

5.3 Various accessories, such as custom made NAB reel adaptors, head/roller cleaning fluids, lubrication fluids, Tentelometers, etc.

5.4 Precision lab-grade spring scales, for tape recorder calibrations on tape tension, brake-force, etc. Three ranges are available: 0-500g; 0-1000g; and 0-300g (1000g=10Newtons=1000p). Price: 30 euro per scale, with shipping.

5.5 Custom made precision NAB reels, 10.5’, for ¼” tape, with box

Price: 35 euro per reel/box, shipping is included.

For Orders: email at

    2. Studer A80, A810 and A820 upgrades and modifications.

These include a complete or partial record and repro card modification with low noise/distortion discrete components and custom made A101 opamp (discrete), as well as custom build film capacitors on the audio path. Newly designed stabilizer cards with ultra-high PS regulation and noise rejection. Both NAB and CCIR EQ cards with precision components also available.

    3. Electrostatic Studio Monitors.

MTSL is offering a limited series of custom made high performance Electrostatic Loud Speaker (ESL) monitors – MASTER ESL. These are the ultimate quality monitors / speakers, aimed at highest quality mastering studios and audiophiles.

These monitors are built by hand, using a MTSL proprietary technology, eliminating the typical ESL technology constraints, e.g. membrane life, membrane loosening and hydrolysis, arching, power/bass handling, etc.

    Introduction -

    Electrostatic speaker systems have been considered the absolute state of the art in audio reproduction since the 1960’s, when the legendary KLH 9 first made its debut. Shortly after, Infinity Systems introduced the Servo Static One, a full range electrostatic design that was considered the best speaker of all time and led to Infinity’s current position as one of the leading speaker brands in the world. In the early 1990’s, Martin Logan popularized the concept of “hybridization”, the process of blending dynamic and electrostatic technologies to achieve a higher level of performance in a smaller physical space. These “integrated” hybrids achieved high levels of sales when they became sleek instead of big and boxy. Electrostatic speakers are known for the clarity and transparency of sound, as well for the very low distortion because amongst others the very low mass of the moving diaphragm.

    An ESL consists of electrically charged membrane or diaphragm, suspended between two perforated conductive plates called stators.  The stators receive opposing voltage charges from the electric music signal, supplied by the amplifier. Those charges move the diaphragm as it is pulled towards one stator and pushed away from the other – a synchronous push-pull operation. As the diaphragm moves, it couples its motion to the air, creating sound waves.

    The diaphragm is manufactured from an extremely thin and lightweight proprietary material, with special conductivity layers. Its controlled conductivity allows distribution and retaining of a polarizing electric charge. This charge is provided by an exceptionally high voltage called a polarizing or bias voltage.

    The stators are very strong and ridged, as well as acoustically transparent. They have a uniform inner surface area and dimensional characteristic to ensure an even, uniform electric field over the surface area of the active diaphragm.

    Advantages of Master ESL compared to conventional dynamic drivers -

    Electrostatic units have many advantages over standard dynamic loudspeakers. Dynamic loudspeakers create sound by using an electromagnetic coil mechanically coupled to a diaphragm supported and centered in a strong magnetic field. This electromagnet is driven by an AC audio signal and the frequency time-varied induced magnetic field that results causes a force to be applied to the diaphragm due to interaction with the static magnetic field. The motion of the diaphragm being coupled to the air produces sound waves. However the cone and the electromagnetic coil have a mass and therefore suffer from inertia. Although the diaphragm, in theory, should adopt a position in direct relation to the input electrical signal, the inertia induces an error in the systems overall capability to follow the exciting signal, over or undershoot adding coloration and veiling to the sound. The magnetic field produced by the driver motor assembly is non uniform outside the limitations of the small gap and as heat builds up due to power dissipation, the characteristics change. Furthermore, the driven diaphragm is not uniformly ridged and adds distortion as a result of the intense forces at work on it. In addition the loading is complex as the inductive resistive characteristics are frequency dependent and make designing a suitable crossover a major difficulty, with inherent compromises to quality.

    This also explains why moving coil loud speaker arrays suddenly come to life at a specific volume setting as the driving voltage overcomes the base line inertia of the driven elements.

    ESLs are not affected by any of these problems. At around 1 mil thick, the diaphragm weight is about 1/280 of that of air. When the diaphragm mass is compared to the mass of the air volume of the listening environment, the diaphragm is essentially mass less. This extremely low working weight almost completely eliminates distortion caused by overshoot or undershoot. Also as the electrical field is to all intents uniform between the two parallel plates the resulting or arising motion of the diaphragm is therefore theoretically perfectly linear, until the mechanical limits of the diaphragm is reached, any distortion shall be of an extremely low order. The bias voltage creates a constant force in one direction that causes the diaphragm to be attracted slightly towards one stator. However, this is very small when the diaphragm tension is correct and should not represent a problem. Due to the uniform electrical field, the diaphragm responds linearly as a moving plane to the applied drive signal. Since the entire surface is being driven, uniformly, there are no losses or distortions caused by any form of mechanical coupling. Only a very narrow zone around the perimeter is restricted from movement due to the proximity to the insulating spacers, and this is normally about just 5mm which is insignificant compared to the overall active area and size of the ESL diaphragm. As an aside since the ESL does not have a low theoretically value of working resistance, the unit does not dissipate power since it is an applied voltage dependent device as opposed to current / voltage transducer.

    Design Issues with other Electrostatic Loudspeakers, addressed successfully for the first time - by the Master ESL series -

    As in any system, ESLs have an extremely complex set of engineering weightings to be balanced in the design consideration stage these are very much dependent on the set in desired design parameters. However, there are some aspects of electrostatic loudspeaker construction and design that are deemed to be extremely challenging and potentially dangerous. Hence, there is very limited availability of quality ESLs on the market. The ESL does not dissipate power - because of its capacitor construction, it stores a potential charge. Therefore, although the amplifier doesn't in theory provide power, the amplifier must dissipate and sink the energy it derives from the lower level input sources which very often results in power amplifier drive problems, this factor causes most standard consumer amplifiers to oscillate in the ultrasonic range or simply self destruct. Also, the stator voltages involved in driving the diaphragm range from 1kV to 10kV. Although the current for the diaphragm bias supply may be a few micro amps, the current in the high voltage audio section can be significant due to the capacitive loading effects of the ESL and the stored energy in the driving systems.

    The ESL also represents a challenge acoustically. It must be operated as a dipole, which means both front and rear must freely radiate into the environment. This can cause the lower sound register to cancel out by interaction from the front to the rear of the driver, which may require some form of acoustic baffles or wave guides. Room placement is critical because the sound may be highly directional. The diaphragm motion is very small, and this requires a very large surface area to provide sufficient sound pressure listening levels. Below its resonance point, an ESL output is virtually non-existent, but unlike dynamic speakers in standard enclosures, there is usually no resonance peaks or dips. Also, because the ESL is incapable of producing sound below its resonance point, bass extension (e.g. ports) is virtually non-existent for most systems.

    The audio signal from the amplifier is transformed in to a high voltage by means of an audio transformer and delivered to the perforated plates as an alternating current. Hence, the construction and integration of the audio transformer is critical to quality performance.

    Advantages of Master ESL compared to conventional ESL -

    The key advantage is based on the MTSL proprietary membrane design, ensuring a controlled conductivity, resistance to humidity/hydrolysis and exceptionally low mass. Thus, the Master ESL monitors ensure predictable impedance over a wide frequency range and subsequently flawless amplifier operation. This means no need for exotic overpriced amplifiers.

In a nutshell, the Master ESL advantages can be presented as follows:

        •Ultra Low distortion

        •Transparency and life-like sound

        •High-definition sound (full detail)

        •High Impedance – easy match with most amplifiers of sufficient power (120W)

        •Realistic sound stage – full depth and width

        •Identical sound levels, regardless of distance to the monitors – very realistic sound pressure levels

        •Virtually not affected by room imperfections and  reflections

Unprecedented personalized aesthetics (custom look, pictures will be available soon)

    Master ESL Specifications -

Frequency range: 18-28,000 Hz with sub; (no sub: 36Hz-28kHz) (+ - 3 dB)

Sensitivity: 92 dB

power amp requirements: 2 x 100-150 W / 4 Ohm

max power handling - 2x 260 W

membrane life: 50+ years

membrane thickness: 0.008mm

membrane H2O absorption - 0.002%

Stator grill voltage: 2.5 kV

Dimensions: 1860-450-40mm (sub: 500x500x500mm)

Price: please contact us at to calculate price, depending on requirements/option

    4. ELP Laser Turntable.

MTSL, in cooperation with ELP Corporation in Japan, offers several models/options of the unique ELP Laser Turntable (LT). This is the only turntable that MTSL deems comparable to professional master tape recorders and master tape sound. Second to none.

While conventional turntables read the record groove mechanically only at its bottom, the LT complex proprietary laser system is the only technology able to read flawlessly the entire information engraved in the groove. The LT Lasers ensure unprecedented accuracy in LP reproduction because they read the entire information of the record groove, without the penetration constraints and respective resonance sound coloration typical for all stylus systems. The LT retrieves the music information from the upper part of the groove that would remain unharmed even in relatively stylus-worn records, as illustrated below. The Lasers capture the music program with exceptional quality and detail, as the lack of physical contact eliminates any record wear or mechanical vibrations and respective sound coloration.

The laser system is purely analog – there is no digitization and any of the issues associated with it, as is the case with all digital formats. Therefore the LT sound is completely free of both digital and mechanical artifacts, common to digital records and stylus turntables, respectively.

Major Features of ELP Laser Turntable: No Stylus - No contact - No sound coloration – No wear - No digitization

•The Laser system consistently reads only pure Analog Audio Signals, without any mechanical obstruction or digitization.

•Laser picks up Audio Signals in the groove areas which have never been touched/damaged by Needles and reproduces Original Sound precisely as engraved on vinyl records.

•If the groove has been damaged by stylus needles, the position read by the beam can be adjusted up or down to retrieve best sound quality.

Note : Lasers are so accurate that they play every particle of dirt and dust on the records, rather than pushing them aside as a conventional stylus would. Therefore the LT creates a lot of Noise and or Groove Skipping if the Record is not clean. However, we also offer a very effective ultrasound record cleaners, to effectively treat your valuable LPs. When your records are well cleaned, the LT sound is simply second to none, comparable only to the actual tape masters used for the vinyl cutting originally.

Professional sound engineers at MTSL, as well as in Japan, heard and determined that the Sound Quality of our Laser-Turntable best approaches the original sound on a master tape.

    ELP's Laser Turntable Price List -

    It is our belief at ELP that analog music on vinyl records does not merely record sound, but a work of Art!
    In pursuit of our goal to faithfully reproduce analog sound on vinyl records, we have made many improvements to our Laser Turntable (LT) since 1989. So far, our improvements have mainly been mechanical and electrical.
    We are now pleased to announce our biggest improvement—We just doubled the speed and doubled the power to transfer Information read by Laser to Audio Signal.
And STILL without digitization!

It is the new model of LT-Master series.
The new Master Series Model has outstanding sound quality, even better sound than before.


  1. LTs are only able to play black vinyl records (no red, blue, green or metal)

  2. Each LT unit includes a 2 year warranty

  3. The following currencies are welcomed

    Australia/AUD, Canada/CAD, Denmark/DKK, Europe/Euro, Hong Kong/HKR New Zealand/NSD, Norway/NOK, Singapore/SGD, Sweden/SEK, Switzerland/CHF, Thailand/THB, UK/GBP, USA/US Dollar

How to get LT

1. You inform us via email which model and what functions you want including your full address and phone number.

2. We send you Pro-Forma Invoice including our bank account.

3. You pay the half amount upon receipt of our Pro-Forma Invoice via wire transfer from your bank to our bank or Paypal.

4. We send you an Order Acknowledgement upon receipt of your initial payment and manufacture LT for you.

5. The balance half amount be paid in 2 weeks before the shipment.

6. We ship LT to you via Fedex in 60-80 days upon receipt of your Order.

They deliver LT to you in a week or so upon receipt of LT from ELP Japan.

Note: The shipping cost from Japan is at your account.