Nak Dragon; do you love it?

I received this today from Naktalk. If you're a techie and have a Nakamichi Dragon, you might find this useful. I've been impressed by the wealth of knowledge from the Nakamichi experts, thanks to all.

I've used Dragons for nearly 20 years in my tape restoration work. They are lovely, but once in a while do need maintenance.

My goal is to provide the best possible transfer for archives' and libraries' collections--typically oral histories more often than not recorded on the cheapest equipment a historian/researcher could find at the last minute using the built-in mic.

Many of these are mono tapes, sometimes with poor coverage of the stereo "right" track.

As you know, the Dragon splits the right track in half and compares the two halves to each other for the azimuth adjustment. It does not use the left channel for any of the azimuth adjustment.

The following description should be done only by someone who is technically competent to go inside a Dragon. I cannot be held liable if you try this and mess up your Dragon. I've done this mod on four or five of my seven Dragons. It meets my needs. I will not modify your Dragon.

About a dozen or so years ago, I modified my Dragons to provide manual azimuth adjustment. It is fairly easy to do:
1) cut the "hot" wire to the azimuth motor
2) connect the end of that wire that goes to the motor to the "arm" of the spare pole on the Timer Play/Rec switch.
3) connect the end of the cut wire from the circuit board to the contact of the switch that is closed in Play
4) connect the non-power terminal of the Gizmo connector (removing the wire going to the circuit board)
    to the contact of the switch closed in Rec

This now allows you to make a small 1x1x3 diecast box with a momentary on-off-on miniature toggle switch. I used a cable gland to secure a small four-conductor cable to the end of the box opposite the switch and put a DIN connector on the other end to match the now former Gizmo connector.

The motor line comes into the switch arm through a small resistor, about 100 ohms, but I forget the exact value. In the centre position the far end of the resistor is grounded. In one momentary position, it connects to the positive voltage already at the Gizmo connector. In the other momentary position, it connects to the negative power already at the Gizmo.

The reason you ground the motor for off through the resistor is to slow it down--it's a dynamic brake.

Now with that mod working, engage it by placing the timer switch into record. I use StereoTool.com that shows a strip chart (I think you have to buy a low-level licence) of azimuth. It's a VST plugin. I generally use one instance for each Dragon I'm using at the moment. You can centre the line in the strip chart and there's your azimuth. I wired my studio for six Dragons, but only have four installed as I needed a third monitor more than two more Dragons--and four Dragons work well with an 8-input interface.

As an aside, I use a combination of Aphex 124 IHF to balanced converters and a custom made Grace Designs IHF to balanced converter. I use a six foot or less RCA-to-RCA cable to connect the Dragon to the converter. The output impedance of the Dragon can be as high as 2500 ohms (with 6 dB turned out of the play level control), so longer cables will provide some high-frequency rolloff.

With the clicking, that means you're at the end of the motor-driven azimuth range. It is possible to use the white azimuth adjustment gear wheel to mis-adjust the play head azimuth so that the motor driven range is more centred on the lousy tape you're transferring. Then you use the motor-driven azimuth (either manual or auto) to correct for the tape.

To set the mechanical azimuth back to correct, power up the machine in auto azimuth mode so the azimuth centres, then switch to manual azimuth on the modded machine and record a mid-frequency tone on both channels and align the play azimuth using the gear wheel. Repeat at several higher frequencies, but the only time you need to really accurately adjust the play azimuth to a new test tape is when you're going to then adjust the record azimuth because if you're close, the Dragon auto azimuth (or the manual azimuth) will take care of that. Few tapes are really dead on, so it's not worth the effort to get the last arc-minute or two of alignment to the calibration tape.

Cheers,

Richard