Otari MX-5050 Review (Reel to Reel Tape Deck)

[AudioSceptic]

Can you share some sources to those figures? I’m intrigued as even amplifiers then had less S/N ratio than 100dB.

When I was at Abbey Road during 70s we heard about Decca using Dolby with good effect. We were sceptical though. We had tried dbx earlier and was not impressed. Dolby brought two A301s (type A) for us to test.

We then measured the Dolby A on a Studer A80 with EMI tape. We measured 83dB S/N ratio at reference level. We had measured dbx earlier. At 86dB it was quieter.

As a test we chained two device groups without a recorder in between. We couldn’t hear the Dolby unit working but the effect of dbx was easy to hear. We standardised the machine room on Dolby units.

We, above were the engineers and some of the managers of the studio.

That tallies with what I read at the time. Dbx could reach a higher S/N but was known for noise "pumping". Is that what you found?

 

[restorer-john]

I’m intrigued as even amplifiers then had less S/N ratio than 100dB.

Huh? Amplifier S/N ratio is measured with respect to full rated power and a shorted input residual.

Specifications for S/N have been >120dB since the early 1980s. Even at a medium 50uV residual and 200wpc@8R (40V) you have a S/N of 118dB.

 

[AudioSceptic]

Be interesting to see what a pro-level machine would do. Ampex quoted about 20-30dB better THD+N than this on the ATR102, as I recall...

I've seen somewhere (Monty at xiph.org I think) that R2R at its best could achieve the equivalent of 13 bits. That would be ~78 dB.

 

[sarumbear]

Depends on the bit-rate. CD/AIFF/WAV uses 10 MB/min, FLAC/ALAC about 6, and AAC/MP3 1 MB at 128k or 2 MB at 256k. Of course you can use (waste) a lot more space by using hi-res.

Even at uncompressed 48kHz 24-bit WAV format you can store more than 4000 hours of music on a 4TB hard drive costing GBP100. That’s 3p for the equivalent storage of a 60m cassette tape but in hi-res uncompressed format.

Compression of any sort has become irrelevant. There’s no reason to store music in anything less than 48kHz 24-bit format.

 

[sarumbear]

Huh? Amplifier S/N ratio is measured with respect to full rated power and a shorted input residual.

Specifications for S/N have been >120dB since the early 1980s. Even at a medium 50uV residual and 200wpc@8R (40V) you have a S/N of 118dB.

By amplifier I meant the amplifier chain.

 

[restorer-john]

Dbx could reach a higher S/N but was known for noise "pumping".

It sure did pump the background in between loud/quiet passages/transistions, but otherwise, it was good. For cassette (at 4.77cm/s) it was better than Dolby C. By the time Dolby S (SR) came along, cassette was finished for the consumer.

The often quoted reason for it not being popular due to the inability to playback on car/portable devices wasn't really valid if you ask me. Anyone who went to the trouble of buying and carefully recording at home, played those recordings on the deck they were created on. I sure did.

A Dolby B recording sounds terrible enough without decoding, letalone a Dolby C. Forget dbx without decoding.

I have an Akai GX-xxx (?) deck floating around here with all three noise reduction systems on it. I'll see if I can find it. dbx II IIRC.

 

[sarumbear]

That tallies with what I read at the time. Dbx could reach a higher S/N but was known for noise "pumping". Is that what you found?

Yes. Very prominent.

 

[MakeMineVinyl]

I've seen somewhere (Monty at xiph.org I think) that R2R at its best could achieve the equivalent of 13 bits. That would be ~78 dB.

As a gross generalization playing back an erased tape will yield a noise level of minus 60 dB to perhaps the high sixties below the reference recording level. That noise level is mostly limited by the tape. There are a lot of variables such as tape speed and track width but how deep into the weeds would you like to get?

 

[Newman]

Gee, it's like nobody has ever discussed r2r tape on any forum before, so this review is their first opportunity to share all their pent-up knowledge and memories about any and all things r2r.

 

[sarumbear]

It sure did pump the background in between loud/quiet passages/transistions, but otherwise, it was good. For cassette (at 4.77cm/s) it was better than Dolby C. By the time Dolby S (SR) came along, cassette was finished for the consumer.

The often quoted reason for it not being popular due to the inability to playback on car/portable devices wasn't really valid if you ask me. Anyone who went to the trouble of buying and carefully recording at home, played those recordings on the deck they were created on. I sure did.

A Dolby B recording sounds terrible enough without decoding, letalone a Dolby C. Forget dbx without decoding.

My comments are on professional use of reel-to-reel.

The success of either format’s success on consumer cassette case was mainly decided at distribution. Dolby who is a world leader in licensing deals convinced every cassette distributor to use Dolby. The early entry to the market of a Dolby chip convinced the manufacturers.

 

[Soundstage]

There are a lot of superb recordings in digital. The problem is the older rock content that is popular so mastered to death.

This. What a shame.

 

[restorer-john]

The early entry to the market of a Dolby chip convinced the manufacturers.

Absolutely. The IC solutions sealed the deal. But with a number of exceptions who refused to jump on the royalty payments train. Toshiba had ADRES which was way better than consumer dolby B, JVC went their own way with their ANRS and even updated it at one point IIRC.

Imagine the royalty payments made to Dolby Labs over the cassette deck years with billions of devices, multiple NR systems and it would have come to a grinding halt if not for home cinema.

First Dolby surround, then pro-logic, DD 5.1 etc etc. An ongoing licensing cash cow. Will it ever end? Not now with Apple keeping them alive encoding all their music with Atmos and making it the new de-facto distribution. It's Dolby for consumer audio software all over again.

I'm sticking to my CDs.

 

[musicforcities]

This was a very cool review. Gives an appreciation for what an awesome job archivists do when they resurrect old recordings and make them sound as good as they do.

Here here! The preservation of magnetic and optically based media is a massive and ever expanding problem for archivist/libraries of record/etc. as is the equipment to read it or even software fir obsolete formats. The half-life of stamped CD/dvds, hard drives, even SSD types, is super short compared to a book, or even film or vynl record. And “burned” cds are considered to be almost as fragile as newspaper from an archival point of view. I

 

[sarumbear]

Absolutely. The IC solutions sealed the deal. But with a number of exceptions who refused to jump on the royalty payments train. Toshiba had ADRES which was way better than consumer dolby B, JVC went their own way with their ANRS and even updated it at one point IIRC.

The problem for those manufacturers was the pre-recorded cassette sales. Cassette sales was big in 80s, it eclipsed vinyl by mid 80s. They couldn’t sell a recorder that didn’t play a Dolby cassette.

 

[Labjr]

Dolby SR (Spectral Recording) was pretty good. Involved multiple bands. The prototype shows how complex it was. I can't find any spec. for S/N except that it improved as much as 25db. Probably because there were many factors like tape types on different machines etc.

 

[iraweiss]

Yeah, it looks like the machine which was used to erase the tape with the 18 minute gap was a UHER.

Any recording device with an 18 minute dropout would be completely unacceptable.

 

[boswell]

Absolutely. The IC solutions sealed the deal. But with a number of exceptions who refused to jump on the royalty payments train. Toshiba had ADRES which was way better than consumer dolby B, JVC went their own way with their ANRS and even updated it at one point IIRC.

Imagine the royalty payments made to Dolby Labs over the cassette deck years with billions of devices, multiple NR systems and it would have come to a grinding halt if not for home cinema.

First Dolby surround, then pro-logic, DD 5.1 etc etc. An ongoing licensing cash cow. Will it ever end? Not now with Apple keeping them alive encoding all their music with Atmos and making it the new de-facto distribution. It's Dolby for consumer audio software all over again.

I'm sticking to my CDs.

Alas, even Toshiba paid Dolby, however

their ADRES was a lot better though, this deck was/is still great, works perfectly but I'm also sticking with my CDs except for some music that that isnt on CD which I move from cassette to flac
btw VU meters beautiful when powered up

 

[iraweiss]

There are many factors that determine the quality of an analog recorder and noise and distortion are just two of them. Frequency response in the audio band, speed accuracy, head alignment to a standard, and speed variations both long term and short term (flutter). Adjusting a tape deck, open reel or cassette, involves achieving a compromise as three things are adjusted: bias, level and equalization. Adjust one and one or the other will change. The objective is to maximize signal to noise, minimize distortion, and have a wide and even frequency response. Some cassette decks had microprocessors to adjust this for you with varying degrees of success. I had a Pioneer cassette deck that did a really bad job with this. Check out reviews here: https://worldradiohistory.com/index.htm and go to Technical and Engineering to read reviews from publications like Audio, High Fidelity and Stereo Review.

 

[restorer-john]

Dolby SR (Spectral Recording) was pretty good. Involved multiple bands. The prototype shows how complex it was. I can't find any spec. for S/N except that it improved as much as 25db. Probably because there were many factors like tape types on different machines etc.

That is a very cool photo of a very complicated prototype.

 

[iraweiss]

Alas, even Toshiba paid Dolby, howeverView attachment 155983 their ADRES was a lot better though, this deck was/is still great, works perfectly but I'm also sticking with my CDs except for some music that that isnt on CD which I move from cassette to flac
btw VU meters beautiful when powered up

As did JVC. Their later cassette decks had both ANRS and Dolby on the front plate.