The TASCAM 85-16 (85-16 and 85-16B)
Last updated 05/30/2007
It’s come to my attention that there are a lot of TASCAM 85-16 owners out there but seemingly very little info on the internet about it. To start, the 85-16 is a 16-track record/reproduce deck which utilizes 1” tape at 15 I/S (IPS or inches per second). The deck uses integrated circuit logic to control all functions. It stands a little under four feet tall and weights 94.8KG (209lbs) without noise reduction. It was one of the first production model 1” 16-tracks and is THE first of its kind which had class-A descreete amplifiers using Field Effect Transistors in the front ends. This means no crossover distortion cutting into the ambience captured by the tape and instead of overloading suddenly like many IC based circuits, it saturates very smoothly like the tape itself. It uses the IEC standard EQ alignment which allows more headroom, less noise and less phase shift than the traditional NAB standard which is more common in multitrack tape machines. They were manufactured from about 1979 to 1984. MSRP was $10,500 USD with the DBX noise reduction unit which would be about $32,000 today.
The 85-16 doesn’t look very impressive on paper, however the
factory specifications don’t do it justice. In reality, a well tuned 85-16 will exceed the factory specs
marginally. The factory states
40Hz to 18KHz ± 3dB using Quantegy 456.
In reality, using Quantegy 499 tape (and probaby 456 as well) will yeild
a frequency response of 30Hz to 19.3KHz + 3dB –1dB. Compared to digital, this sounds like a huge variance. However, this is mostly offset by the
resonance of the playback head which occures at 60Hz. In actuallity, this +3dB “head bump” is
quite useful and actually allow the user (in a rock recording situation) to use
less EQ in post production. The head bump is caused by magnetic fringing. That is to say that low frequencies create a sort of halo around the heads that gets printed onto the space between tracks. The lower the frequency, the greater the fringe effect is. On playback, this electromagnetic fringe is induced into the playback head thus creating greater power at extremely low frequencies. This of course reaches a peak and then starts to drop as the frequency goes below the limits of what the head can reproduce. This
sounds backwards but almost all rock music engineers boost 60Hz on bass drums
and often even electric bass.
Since the head bump is about +3dB at 60Hz, the need for such EQ is
reduced or eliminated. Other
common instruments do not contain much energy at this level and are thus not
adversely affected by it.
Furthermore, since the frequency response rolls off smoothly and
naturally, musical information can be tracked past 21KHz.
The signal to noise ratio is (C-weighting) 65dB-68dB without noise reduction and 95dB-98dB with DBX depending on the set up levels and tape stock used. Most digital enthusiasts would claim this is really bad. However, that is because in the digital world, it is bad. With digital, the noise floor also defines the dynamic range. Using an excellent 16-bit storage system with good convertors, 96dB is the signal to noise ratio. Below this level, there is NO information at all. That is because in digital, there theoretically is no noise at all but details in the sound which occure at a lesser level than this are “plateaued” off into either a higher or lower voltage which turns into a constant distortion which we percieve as noise. In the analogue world, the noise is an addative side-effect of tape. That is, the noise really is noise and not the result of information being lost. In fact, detail can be percieved 20dB or so below the noise floor giving a total dynamic range closer to that of 113dB! Now even though a 24-bit system can theoretically resolve 144dB of total dynamic range, the class AB integrated circuits in most Delta-Sigma convertors cause crossover distortion around 120dB below full scale. That combined with the poor clocks often used in lower-middle of the line convertors severely limit the usable dynamic range. Even though the usable dynamic range of the tape machine itself is only about 113dB compared to the 120dB or so on a 24-bit system is still less, you must remember this is going to be mixed through an analogue board where some instruments will be pulled down below unity which further disguises the limits of the dynamic range. Mixing digitally recorded material through an analogue board will give similar results, however the tendancy as of lately is to mix using digital signal processing which actually adds to the distortion and percieved noise rather than reducing it.
The optional features of the 85-16 also add greately to the value of such machine. Even though the 85-16 is much quieter than most computers with their whirring fans and hard drives, the remote control allows the unit to be operated in a closet space further reducing noise. The remote cable can be long enough to control the system from an entirely different room if one so choses. The remote is 2 standard 19” rack spaces and includes record arm functions, auto-locate as well as transport functions. The 85-16 also includes a pulse sync output from the capstan motor allowing several units to be synchonized directly off of a single master unit. This can be done without losing a track to time code. However, the sync is relative and the tapes must be queued manually. A drumstick clack before the beginning of each song is a good reference point. Never-the-less, synchronising 2 units with nothing other than a special cable is a great advantage. Since the DBX is switched manually on a track by track basis, a single track can be set up to record SMPTE time code to one track for the purpose of synchronizing video/film or other audio equipment not compatable with the sync output from the deck. Automation of an analogue or digital board can be set up using the same function. The crystal sync for the capstan motor can be disengaged to allow a ± 10% shift in record/playback speed which is handy for making recording easier or for special effects. The pulse code is taken directly off of the capstan so applying a pitch shift will also effect other devices connected to the 85-16.
The overall construction is quite rugged and reliable compared to most modern recording equipment and one can expect their 25-year plus machines to outlive most any modern equipment, particularly DAWs. Many people have pointed out the idea that the 85-16 is not a serious industrial studio machine. Even though there is better equipment than this middle-of-the-line analogue 16-track, it still beats almost everything in studios locally in sound quality, longevity and operational ergonomics. This little workhorse sounds better than the “more serious” MCI 2” decks in most people’s opinions and is certainly cheaper to operate. It’s the perfect solution for mid-level studios who don’t want to be forced into ProTools or other computer DAWs without spending the cash on 2” tape. At any rate, with an original price tag similar to that of a new car, it was still a serious commitment for any studio owner. The original orange legs of the 85-16, the result of a miscommunication with the marketing department, won it the name “Flamingo”. This was fixed in the 85-16B. The 85-16B is nearly identical to the original with the exception of the color and slightly more flexible internal signal routing.
The setup requirements should be as follows. For Ampex/Quantegy 456 or similar, operating level should be 250nW/m with about +3dB overbias at 10KHz. For Quantegy 499 or similar, the operating level should be around 400nW/m +4dB overbias. If you are using noise reduction, there is no need to go above these levels as the noise floor should be near 16-bit noise levels. Recording hotter signals will simply take away the transient response of the signal making for less clarity on tape. If you wish to disable the noise reduction, you may record at 370nW/m for 456 and 520nW/m for 499/GP9. However, this will eat into your headroom quite a bit. Some people may comment that this deck is not suited for newer stocks like 499 and GP9 but this is not the case. The motors are more than able to handle the thicker oxide. The internal headroom of any tape used on this deck will saturate before the electronics will. Even ATR which is meant to run hotter than any of these listed stocks will saturate before the internal electronics of the machine. The overbias settings are specific to Quantegy for .25 mil tape heads such as those on the 85-16. Other companies may have different requirements.
In order for the DBX noise reduction to work at its optimal performance, the deck must be aligned within .5dB of its intended operating levels. Failure to match these tolerances can make for a very compressed or expanded sound on playback. The user manual has no instructions on aligning the DBX unit. However, it needs to be done as regularly as the deck itself. Electronic adjustment is a fairly straight forward procedure. Align for playback and record of the deck without DBX in the normal fasion. Play pink noise through the deck at 0dBVU on all tracks. Engage the DBX and adjust the DBX encode level pot (R105) till the VU meter of each track reads 0dB. Record the noise for a few minutes on all tracks once the enceded level is adjusted. Rewind to the beginning of the calibrated noise. Play back the noise watching the levels for each channel on an external device. Adjust the playback trim pot (R104) till the playback levels are the same on the external device with or without DBX. Unlike the amplifier cards which have the trim pots on the front, is impossible to adjust the trim pots of the DBX cards without an extension card as the pots are on the side. Fortunately, the DBX cards are the same as that used on the Teac 80-8 so spares are readily available if needed. Unfortunately it looks as though the 85-16B uses a slightly different card and it is uncertain as to whether the cards are interchangable but the extension card SHOULD be the same. Also, do not use digital meters for this job but rather, high quality VU meters.
I’ve heard of these machines being modified to run at different speeds or even including a selectable speed such as 7.5 IPS/15 IPS or 15 IPS/30 IPS. I do not know how to do this and would not recommend making such modification. To run this machine at 7.5 IPS will double the record time of your tape but at the expense of high frequency loss. It would also require around 7dB overbias which will degrade the signal quality due to intermodulation distortion. Running the 85-16 at 30 IPS will smooth out the noise making it less intrusive for those not using DBX and will extend the HF response but you will loose the bottom octave of your music and the head bump will be raised to an intrusive 120Hz or so.
Another common mod is to replace the record/repro head with a higher quality one preferably with a slightly narrower track width to reduce fringing and lower resonant frequency. By mixing from the monitor head, the head bump is thereby eliminated at the cost of some extreme low frequency reproduction.
The shielding in the 85-16 isn’t the best so the capstan motor creates interference which is picked up by the output amplifiers. It is possible to add additional shielding particulary around the head block which will reduce the mechanical noise. Shielding can also be added around the capstan motor.
The relays in the DBX unit are unsealed mechanical types which are best replaced with solid state relays. This will greatly increase the reliability and quality as well as extend the life of the unit. Though DBX claims maintainance is not needed on these modules, any 85-16 owner will tell you the DBX causes more problems than the deck mostly because of these relays.
While the electronics are suprisingly good in the amplifier circuits themselves it is possible to replace them with more advanced quiter electronics. Though this is an expensive process it can extend the signal to noise ratio beyond 108dB and the resolving capabilities of the tape itself to 120dB.
If anybody has suggestions on information that should be included in this article, please E-mail the author.
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