Nakamichi System Two

After a quest for years I finally succeeded in building a Nakamichi System One, an audiorack including tuner, cassette deck, pre- and power amplifiers like no other I’ve seen so far. The ingenious setup by Nakamichi is space efficient and flexible due to the trolley wheels in the basis. Enjoying this System One for a while I’ve set out to build a successor of the infamous Nakamichi System from 1975. The goal was to place a considerable number of cassette decks of my collection within a flexible and movable setup, much like the System One houses the Nakamichi series 600.

= Some of the vintage Nakamichi products are equipped with 19inch mount facilities. Like the example shown, the model 680ZX with additional 19inch flap, bolted on the front left. I’ve not seen these 19inch mounts being put into use much though, mostly these mounts contribute to the professional image of the gear involved and the brand name Nakamichi. But I can see the use of this feature in accommodating the Nakamichi’s in a space-efficient housing. So my interest for 19inch racks emerged and I scooped the internet to get my hands on an unused rack somewhere. Part of the hobby is to achieve the goals without purchasing ‘new’.

As so often, from a unexpected source an offer followed soon. The 19inch cabinet on hand was sleeping in a personal depot of an acquaintance for some time. Wanting back the space occupied by this cabinet he was willing to part with it for a reasonable price. His original intention was to store a complete audio system into this cabinet in an attic music room, but a sloping ceiling prevented the cabinet to be placed conveniently into the designated space. The cabinet was brought to me by use of a van for transportation. When I looked into the van I was overwhelmed by the sheer bulk of this professional 19inch cabinet, looking more like a computer room contraption instead of a domestic storage facility.

Although it seemed unrealistic at first, I was challenged to turn this huge, professional 19inch cabinet into a domestically suitable Nakamichi system. I took the liberty to name this the System Two in line with the original Nakamichi nomenclature.

Biwired Mains

I’ve always looked with envy upon the mains cable sourcing in the Nakamichi System One, flowing to and through the System One Timer/Clock. Although quite practical, the thin and lengthy mains twin lead used for the complete system goes directly against my purist ideas about unrestricted and clean power sourcing. So I decided to customize the power cabling in the System Two and usage of higher caliber power cords. That is to say, the single primary power lead to the mains outlet is a lengthy (practicality is the issue here), three way 1,5 mm² cable, twice the size of usual mains cable. The third “ground” wire is led into the cabinet and straight to a centralized earth point to which all cabinet panels are grounded. For the audio gear this central earth point can be used too, if so needed. In fact this is the only way to connect the gear to ground, for the internal power sockets are completely lacking earth lines, to avoid possible loops in the multiplicity of power connections.

The use of twin wire for the internal power connections was the logical choice since there would be no earth leads involved here. Three way power cables were available in 1,5 mm², but domestic twin wire supply was limited to 0,75 mm² only. The apparent philosophy being; high current power applications require higher gauge wire and must be equipped with decent earth facilities. As an alternative I could have opted for some decent loudspeakers cable, but choose to stick to visually standard power cords for the internal mains wiring. To allow for a minimum of 1,5 mm² gauge throughout for the power lines I doubled the internal connections using standard power cords, sort of biwiring all internal mains provisions. (Pun: biwired mains might become the new hype as a follow up to the popular biwiring of loudspeakers.)

The biwired mains connections run via the 20 amp heavy duty professional switches that came with the cabinet towards the arrays of mains sockets. Each bank of three sockets is provided with it’s own 1,5 mm² twin power cord, providing ample power flowing to each connected devise.

Convenience facilities

Additional power provisions (using normal single power cords, the mania has a limit) were made to support the internal lights and the fan at the backpanel. The lights help dealing with internal connections and building the internal support for all gear making life a lot easier. Also the light shining through several slots in the exterior complements the lights from the different gear very nicely in the finalized setup.

The built-in fan offers cooling when needed, but the professional mains powered fan made too much noise to be practical when listening to music. Two banks of large high current resisters offer several stages of reduction in voltage, allowing three running speeds of choice. Each resistor triplet is dissipating the 23 watts of consumed power. A single resistor for this application would require a very large resistor. For cooling purposes the resistors are glued directly to the large steel backpanel on which the fan and switches are mounted as well.

Two sides to the coin

The bulk of the cabinet at first raised doubts adopting it at home. It’s use would be to store a number of pieces in my collection in as less space as possible. The use of the 19 inch front could probably house 6 cassette decks, 10 maximum when using smaller Nakamichi’s. Storing as little as 6 pieces in this large cabinet would overshoot the mark, I considered. The cabinet’s internal space would only partly be occupied because the depth of the Nakamichi’s was only a fraction of the 80 cm of total depth of the cabinet. The back half of the cabinet would be vacant and wasted space this way. So the idea developed to utilize both sides of the cabinet. The cabinet can be turned around on it’s wheels to face the selection of Naka’s to be used at will.

Utilizing the backside was feasible by rearranging the internal rackmounts to the back and by reducing the length of the supporting bars. The latter avoids conflicts when placing the individual Nakamichi’s in the front and back, because the shortened supports no longer interfere with the front mounted gear.

The total setup would now be able to accommodate 11 to 13 Nakamichi’s and made the whole idea of building this system worthwhile. Besides that, this unique solution for storing a collection of any type of gear and is just fun to conceive and build.

Connected

The general idea of how to put this system together had formed and some internal arrangements were in order. The inside of the cabinet was laid out with double sets power sockets, the “front” and the “back” each got a individual set at their disposal that was separately switched by the two originally provided 20 amp switches. Power connections suffice for up to 6 Naka’s at each side.

Playback

Additional work was needed to provide for the connectivity of the audio-leads. Up to 12 out- and in-flowing stereo cables can be connected to the set of Naka’s. That’s a total of 48 cinch cables going somewhere! A bit more then even the most extensive stereo or multi channel amp can provide for. At first I concentrated on playback connections only. For this I built a switch box using a twelve way switch to switch 12 inputs to three parallel outputs.

Up to three outputs can be handled without to much signal degradation and can relay the signal to outboard noise reduction units, like the Nakamichi HighCom and Dolby NR200. In total three sets of cords can flow out of the System Two, delivering direct, HighCom decoded or Dolby C decoded signals from every one of the 12 sources. Of course all possible direct hook ups for optimum performance can always be established at will.

I know I can reduce this number of outgoing cables further by putting the Noise reduction units in series after the switch box, which is feasible due to the by–pass switches in the noise reduction units of Nakamichi. But serializing like this would mean the introduction of 2 to 4 buffer amplifiers, several additional cables and even more connectors getting in the way of signal quality.

The switchbox itself is already in the signal path and unavoidable if convenient output switching is desired. To avoid the loss of signal quality as much as possible 2,5 mm² solid core cable was used for connections inside the switchbox.

Second Box: Recording

For recording a single signal cable can be connected to any of the decks ad hoc. This provides for the most direct and clean record feed and is the preferred option for quality taping. For less demanding recordings the record feed can be divided across up to twelve parallel cinch lines in a second switch box. Dividing a record feed over 12 decks simultaneously is unwanted because of signal degradation, but the setup is flexible and will support it. Additional amplification or buffering would really be required when more then a few parallel lines are used.

Mutiple inputs are catered for and selectable (6 way). Each input has two parallel connectors, so a single , unshared direct connection to one of the decks can be established for each of the six available sources. This unshared connection is assured as long as the corresponding input is not selected. When selected the direct connection is paralleled with all the at that point connected recorders.

Enough said, suffice it to say the switch boxes are layed out to create an array of options of which some will supply an as pure and uncompromised recording signal as possible. The switch boxes are mounted on the 19 inch faceplate the logo is written on, and two large, stylish knobs are located next to the logo of this System-Two.

End result

More details were dealt with to get the cabinet as flexible as possible in housing and rearranging the Nakamichi components. The front of the cabinet is suited for 19 inch mounting only, the back can be used for both 19 inch mounted as well as standard 43 cm components like the Dragons, LX, ZX, and other Nakamichi series. This is accomplished using the internal 19 inch rack for one and the modified internal rackmounts on which the components can slide into position. These rackmounts were adapted to fit at any height so the varying sizes of the different components are easily accepted.

Front

The flexibility allows to play around in different line ups of components. The front lined up with the three 1000’s in my possession looks like this (supplemented with an very fine other Nakamichi machine, the 680 ZX). The link from the photo will show more.

Back

Using for example 5 RX turning cassette decks, intriguing decks nicknamed ‘oriel’ will fit nicely at the backside.

Or a series of top quality decks all using the same famous Double Capstan Diffused Resonance tape transports, although in differents formats. The link from the photo will show more.

PS: Special thanks to Arie Vogelaar who supported the project and assisted with all the mechanical adaptations.