Sony TA-N7B

Sony TA-N7

1 9 7 7 april 1977
1 9 7 9 1979

One of the very very few units I wish I'd own... which I do own :-)

A masterpiece of understated looks holding six pairs of Sony's original VFETs.
With the pre-Esprit TA-N88B, the TA-N7B was alongwith the TA-F7B integrated the last Sony unit to sport V-FETs and a fairly different design because of its hybrid BJT / V-FET power section and power cascode circuit, the latter feature having been revived by Sony with the N7B, then, much later, by others aplenty.

Fully DC, with two transformers for the regulation, two toroidal transformers for the power stages and a total 88,000µF of caps. The frame structure and back "holders" are made of diescast aluminium. The toroidal trafos were custom-ordered to Nippon Kinzoku, a company still in business today which must have provided most if not all toroid trafos to high-end JP hi-fi throughout the 70s and early 80s.

The "B" color varies from the dark grey of some versions to the soft greenish/bronze of others... It seems however that these color differences were restricted to a few pre-production samples as all produced N7B have the "euro" bronze tint.

The TA-N7 is silver and is extremely rare : less than a hundred made.
Silver units have the name and model number silkscreened on the front while the "B" units have it stamped ; the first export production run was the silver one, very quickly changed to the "B" color.

The hardcover hiding the four center caps was only available on european models.

Just as for the TA-8650 / TA-5650 / TA-4650, there are a few safety mods to be performed before using a TA-N7B daily - flaky diodes, resistors, bias current, DC offset etc.
DON'T power your N7B until you have had it checked by a serious tech who really knows what V-FETs are !!!

The TA-N7B can be seen as an early equivalent of the DTC-2000ES recorder, the SS-GR1 or the MDP-999 Laserdisc monster - statement units produced when things have got to be shelved because they're too expensive - a last hurrah of sorts.

If the Yamaha V-Fet amplifiers are somewhat "muscular", the TA-N7B and TA-F7B are just a bit more laid back. It may be a bit deceptive at first but in the long run... definitively better.
The N7B's sound is however difficult to describe because there is no "sound" - just pure musical bliss.

The production run must be around 3000 units, worldwide and all versions included.
At least #1976 sold in Japan, at least #82 for the (short) EU silver run, about #600 for the EU bronze run and under #100 for the US version.
Given that at least half of these went bust, were junked or eaten up by sea salt in Japan, the N7B is now... quite exclusive.

A real japanese N7 (bronze color, marked "N7" (front) / "N7B" (back), black spk terminals), repaired 86'10 and 08'88 here.

Sony TA-N7B, image 1 Sony TA-N7B, image 2 Sony TA-N7B, image 3 Sony TA-N7B, image 4
Sony TA-N7B specifications
Title Value
Continuous RMS power : 2x 100W (20Hz...20Khz, 8 Ohm)
Power bandwidth : 5Hz...35Khz (8 Ohm)
Damping factor : 100 (8 Ohm, 1Khz)
THD : less than 0,01% at rated output
less than 0,008% at 1W/10W output
less than 0,01% at 205mW...rated output
IMD : less than 0,01% at rated output
less than 0,008% at 1W/10W output
Frequency response : DC...100Khz (+0 / -1db, Direct input)
6Hz...100Khz (+0 / -1db, C-coupled input)
S/N ratio : more than 120dB (short-circuited input)
Residual noise : 0,024mV (8 Ohm)
Direct inputs : 1,3V for rated output / 50kOhm
C-coupled input : 1,3V for rated output / 50kOhm, 3Hz cutoff
Outputs : 1 pair of speakers (8 Ohm or more)
PC : 480W (UK)
420W (AEP)
160W (USA)
350VA (Canada)
Dimensions : 43 x 17 x 33,5cm
Weight : 20,1kg
Finish : TA-N7 = silver panel (EU ; first export batch only)
TA-N7B = green/bronze (EU, US, JP)
DC bias adjustment: 30...70mV DC with no signal input
V-FET ranking : When replacing the three P channel 2SK60 and/or the three N channel 2SJ18
in each channel, use three matched ones which have the same Vp (pinch-off)
voltage rank figure printed on them.
The fluctuation of the Vp rank of the three can be acceptable on a one-rank-difference basis.
Sony TA-N7B : 1 topic
(last updated topic shows up first)
  • Sony TA-N7B Advice                             (14)last updated by hifihouse - 25/01/2012, 04H16
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