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Category: Tape Decks

Tandberg 3014A: 680mV vs 580mV – Myth or Reality?

   Some experienced technician claims that the reference level specified in the service manual was wrong listed for all the Tandberg 3014A models. The service manual specify 580mV at the Dolby chip test points (TP4) when using standard Dolby test tape like Teac MTT-150 (400Hz-200nWb/m ANSI). The Tandberg level test tape is based on 1kHz/250nWb/m […]

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Noise performance analysis of Op-Amps

I. INTRODUCTION    In a previous research we discuss the design and performance of J-FET discrete input ultra low noise preamplifier with voltage noise less than 0.3nV/ЦHz [1]. The circuit has significant benefits compared to the simple op-amp use but it is not suitable for some low scale and low power devices. Front transistor used […]

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Tandberg 3014A: rebuild & review

Part 1 – Introduction    It is a post commenting repair & upgrade process of one interesting cassette deck. I will make a detailed review of this model due to its unique circuit design (reduced use of negative feedback stages). The idea was to repair some problems, calibration, replacing the old parts that grow old and […]

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Time constant mod for the Revox B750 MK-II

   Revox B750MK-II is very interesting amplifier. It integrates nice RIAA EQ preamp for MM cartridges. After changing all of the capacitors and transistors, its sound is very impressive. First of all it is a current feedback amplifier. The power amps sound pretty at all. This post is purposed to the RIAA EQ of the […]

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LNA2104 – Ultra Low Noise Preamplifier

   The amplification of low signals from inductive transducers is not an easy task. Existing integrated amplifiers are good enough but in some applications the requirements are for better signal to noise ratio and high gain. For example the LT1028 / LT1128’s voltage noise is less than the noise of a 50Ω resistor. Here we […]

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Reel-to-Reel Project @LAB2104

   Engineers from the Laboratory of Embedded Systems (LAB2104) at Technical University – branch of Plovdiv,  started a new project for developing of contemporary Reel-to-Reel tape deck. The project includes partnership of some companies, like HWGroup (which have experience in development of smart MIDI mixers for Harman Kardon) and Technocity (one of the biggest new vinyls […]

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Phase compensation in tape recorders – stay close to the original

   Phase compensation is a method for correcting the time problems on spectrum in magnetic audio recording. These compensation networks are provided for the record amplifier circuitry, also for playback amplifier. These networks enable the circuit to be optimally compensated for group delay introduced by the record equalization circuitry with separate adjustments for both operating speeds. The result […]

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Frequency response of original tape decks

What’s New: 09 Dec 2017: adding Technics RS-B905, Aiwa Excelia XK-009, Pioneer CT-93, Pioneer CT-S830S charts; 01 Oct 2017: adding YAMAHA K-1020 chart; 28 Aug 2017: adding TEAC V-7000 chart; 27 Aug 2017:  adding a Nakamichi ZX7 chart;    The frequency response of the playback channel is important for sound signature of every cassette deck. The standard was […]

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Cost for Tape Decks repair @LAB2104

   The repair of cassette & tape decks is complex process. These machines consist of electronic parts and modules, also a mechanical once. Both needs to be serviced. The most common problems in electronics are the old capacitors and ICs. All of the capacitors need to be replaced with good ones for best final results. […]

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Test equipment @LAB2104

    The LAB2104 is situated at Technical University in Plovdiv – Bulgaria. Bulgaria is a small country in the European Union and Plovdiv will be the European Capital of the Culture in 2019. The laboratory specialize analog magnetic recording in parallel with the research on the embedded systems and electronics. About the magnetic recording It […]

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