Otari MX-5050


The Otari MX-5050BII Series Recorders are professional two-speed reel-to-reel tape recorder/reproducers designed for optimum performance and long life.

The MX-5050BII units use 1/4-inch reel to reel tape and are available in 4 different head format models:

Otari MX5050
  • BII-2 2-track, 2-channel
  • BII-4 4-track, 2-channel
  • BH-F Full track, Mono
  • BII-2E 2-track, 2-channel DIN

The MX-5050BII is set to operate at tape speeds of 15 and 7-1/2 ips by the factory. However, it can be converted to operate at 7-1/2 and 3-3/4 ips.

What are the best features of Otari MX5050?

Otari MX-5050BII is equipped with many professional and useful features:

  • Switchable 2-tracks or 4-tracks playback
  • Both NAB and IEC equalisers, switchable on the rear panel
  • Edit control that permits spilling
  • Adjustable cue for audible monitoring in the fast-forward and rewind modes
  • SEL. REP. function for overdubbing: for example, SOUND WITH SOUND, SOUND ON SOUND
  • Built-in two frequency low distortion test and cue-tone oscillator,
  • Computerised digital time display, a memory stop for automatically stopping the tape in the rewind mode at a predetermined position
  • Bias, equalisation, and level controls adjustable from the front panel
  • Active balanced input and output circuits
  • Reference level output switch and reference flux level indicator on the front amplifier panel
  • Separate line and microphone input level controls for each channel
  • Switches for recording levels, equalisation, microphone, and output level attenuators.

Service Manual and Alignment Procedure

Everyday Use of Otari MX-5050BII

Otari MX-5050 tape machineOtari MX-5050 tape recorders are real workhorses with low maintenance need and very rugged construction. They were used by lots of radio and TV stations for years and also utilised in many recording studios as a mixdown machine.

Consumers also bought this machine because it was reliable, high quality and relatively cheap because Otari never marketed to consumers, the tape recorder was built to production studio standards.


The construction is fix and rugged, you will not have any problem with it. The tape transport system is very good and reliable but not refined, Lyrec and Nagra tape transport systems are better.

The sound quality is very good, the sound is robust the frequency response is pretty flat, without any coloration of the sound. However, the audio electronic of top studio machines are better producing a more refined sound. All in all, Otari MX-5050 tape recorder is a very good tape recorder and the best one in its price range.

Otari MX5050BIISpecifications

Track system: 2-track, 2-channel, stereo system

Heads: 1 x 2T playback, 1 x 4T playback, 1 x record, 1 x erase

Motor: 2 x reel, 1 x capstan

Reel size: 7 or 10.5 inch reel

Equalization: NAB, IEC

Tape speeds: 7 1⁄2  15 ips

Wow and flutter: 0.06% (15 ips)

Frequency response: 30Hz to 20kHz (15 ips)

Signal to Noise Ratio: 66dB

Total harmonic distortion: 0.5%

Dimensions: 527 x 430 x 225mm

Weight: 24kg

Finish: dark grey leather finish

Otari MX5050 Review

How to buy a good Otari MX-5050BII?

Otari MX5050 service manual

Is it worth to buy? Absolutely!

When you buy an MX5050, buy BII-2. BIII is a bit better, especially the transport system but more expensive.

There are some problems; you should be aware of.

Some machine may have really worn heads, but you may still be able to get them re-lapped or change to new ones and make them perfect again. Some Otaries may have problem with grounding. The screws that were binding the circuit cards to the chassis got loose or corroded, causing grounding problems.

Many of these machines wired the balanced output out of phase. This may or may not be an issue for you. Many folks cannot tell if the recording is out of phase or not.

Otari MX5050 does not have single-ended outputs but balanced both in and out. A simple way to connect the machine to a single-ended system is with the use of balanced to single-ended adaptors like:

A well-performing MX5050 in good alignment and careful calibration will give you an experience near any of the so-called "holy grail" reel to reel decks. These machines were built to a far higher standard than any of the consumer machines.

Otari MX-5050 BII-2 tape recorder for sale

The machine is in a great condition -- nearly mint, refurbished, serviced, aligned and calibrated for SM468 tape types. The pictures above are taken from that machine.

Here is a short list of adjustments:

  • Tape transport system alignment
    • Brake adjustment
    • Capstan pinch roller pressure adjustment
    • Reel table height adjustment
  • Checking the supply voltage
  • Tape speed calibration
  • Servo offset adjustment
  • Demagnetizing
  • Reproduce alignment
    • Reproduce head azimuth adjustment
    • Reproduce level adjustment from calibration tape
    • Reproduce amplifier system frequency response measurement and adjustment
  • Record alignment
    • Adjustment of bias trap
    • Recording head azimuth adjustment
    • Input and Record level calibration
    • Low frequency compensation adjustment
  • VU meter calibration and checking the overload indicators
  • Checking oscillator frequency and RF voltage

1,990 euro SOLD