Originally Posted by RamblinE
Finally got my hands on a turntable worthy of a sturdier rack. The NAD 5120.
Sorry about the trash on the desk. I was eating chips and salsa.
That tonearm is indeed flat. It's a PCB. The headshell leads are soldered to points on the underside of the arm. The arm "unplugs" from the unipivot base. Hell it even bends and flexes. I believe the flexible arm is supposed to eat up resonances and vibrations where a more rigid arm transmits them. The platter is neat too. Thin waffer of metal with almost an inch of rubber mat on top.
Even with a cheap AT92E on it, it's the smoothest, most linear sounding turntable I've had yet. This thing is worthy of a new belt and a better cartridge as soon as I can make it happen.
The real name of this extraordinary design is Tesla NC 470. Designed in early 80s by late Jiri Janda of Tesla Litovel from what was then Czechoslovakia. The same factory today produces Project and MMF tables at lower end of the price spectrum and EAT in the higher priced echelons.
It is the most innovative and cunning design I ever came across. It most definitely puncehes far above its weight. The main idea was to use the laws of physics to the benefit of extracting most info from the grooves, not trying to achieve the impossible by fighting physics. Its most unique feature is the flat tonearm made out of PCB material - arm is meant to be floppy in the vertical direction and to be very rigid in horizontal direction, much more so than tubular arm can be. In addition, it has dynamic antiresonator counterweight, which can be tuned to the exact frequency and Q in order to reduce the effects of that enemy #1 of phono reproduction, the cartridge/arm resonance around 10 Hz. The result is firmness in bass that has to be heard to be believed.
Since about november, I have bought three of NAD 5120s, as it was called for export to the West. It is FAR from being a finished article, but its potential is so high it is worth any trouble. It is the singular most powerful proof of the saying you must never judge the book by its cover - or turntable by its looks. When I first saw it in late 1982 (or was it 83 ? ) at our Electronics Fair, it looked so plasticky with its rubber platter and outlandish tonearm, that compared to immaculate looks of the Revox at the adjacent booth made it look like a toy. The people from the factory did not speak English and at the time my knowledge of Czech/Slovak was zero. The beautiful hostesses had no technical knowledge - so reluctantly I went away without learning any real info about this ugly duckling.
The thing is made to a price point, it is not an all out assault with the best materials and/or execution - yet the basic idea works so well that it is worth developing further. The main drawback - it is very poorly shielded from hum - besides normal 50/60 Hz hum you will get high frequency buzzing that is subdued to acceptable levels only by using low impedance cartridges. Any normal MM will buzz.
The flat floppy arm has a nasty vertical/torsional resonance at approx 150 Hz, mostly affecting the right channel. It was issue enough that NAD came up with a normal tubular arm version later on. It does not exhibit so pronounced resonance(s) at around 150 Hz as flat arm does - but the magic of midrange and treble flat arm poseses is missing.
The entire arm is detacheable from its bearing ( it is NOT a unipivot bearing ) - via 4 pin DIN connector - in seconds. You can have sound from the preadjusted arm/cartridge combination(s) ( geometry, tracking force, antiresonator frequency and Q - all preadjusted ) back in about a minute - you just have to set the antiskating for the arm//cart in use; only half a minute more is required in case you have to adjust the lift height if you change from flat to round arm or vice versa. This possibility of changing the entire tonearm is fairly rare; Technics EPA 250/500 had it ( along with fixed nonadjustable antiresonator on 500, adjustable on 250 ), Keith Monks arm had it, as does VPI today. It is by far the least expensive of the bunch with this capability.
Viewed from today's perspective, most annoying omission is the total lack of possibility to adjust VTA. Due to construction of the arm mounting/bearing, very hard to do, even at cost no object level of construction.
If above sounds like bad rep - it is not meant that way at all. A properly adjusted stock Tesla NC 470 / NAD 5120 / Lenco L 802 with any cartridge not exceeding 8 gram or so of mass is a formidable turntable as it is. You would be really hard pressed to get this kind of high SQ at anything like several times the price of the Tesla/NAD/Lenco. Yes, it was really sold under all three makes/models.
As it is a predecessor of many current Projects with which it shares motor, it can be used with Project ( and Music Hall ) Speed Boxes. A neat trick is to place the belt on the pulley meant for 45 RPM, select 45 RPM on speed box - voila, 78 RPM ! - besides all the improvements usual for external power supply.
Here one of the vidz on YT - round arm, orange single to show the rubber platter, and "new age" mod with blue LED ( the only thing I hate and object to in audio looks/design ) - original had orange neon lamp or in later versions ( built from 1983-1995) a red LED. Single knob operation for both on/off and tonearm lift - once you get used to it, very convinient. http://www.youtube.com/watch?v=TPf9kSij33Y
I intend to tie the loose ends in this design to allow its potential to really shine. Although it would still look pretty much the same, the mod will be an entirely different animal. Goodness is achieved by proper basic design - which NC470/5120/L802 has in spades. Excellence by attention to detail - something beyond reach at the original price and the possibilities of 30 years ago.
If you run across one, give it a try. It is more work to get the antiresonator adjusted correctly - but once experienced the performance of which it is capable, you will find going back to normal arm really hard and unacceptable.
Warning - that counterweight atiresonator is VERY susceptible to demage in shipping - it absolutely must be prepared for shipping as described in user manual. Not that it can not be properly rebuilt if it snaps out of place - but it is annoying and time consuming procedure that can be avoided by proper packaging.