N9EWO Review : Japan
Radio Co. JRC NRD-630
DSP HF Receiver
The JRC NRD-630
DSP HF
Receiver. DSP based yes, is it one of JRC's best....NO
in our testing !!! According to JRC, the NRD-630 was designed as a marine training radio (info via Rob Sherwood).
While it might be a extremely well made premium HF receiver, the overall performance and audio quality
were a fast downhill silde in our hands on testing! Looking at Sherwood Engineering NRD-630 lab numbers (click here), it's IP3 Dynamic Range at 2 Khz spacing comes in at only 70db.
That is a very sad showing for a pricey modern DSP premium receiver if you ask me ! (N9EWO Photo)
(I
do
not own JRC NRD-630. A borrowed sample was used for this report)
Firmware/Software
on tested sample
: 1.4 1.1
(This is how it was displayed). I believe the 1.4 is for the DSP
and the 1.1 is the Operation Firmware ? I was able to see the
sticker on the EPROM IC next to the DSP IC’s and was marked
as 1.4 , I was unable to get easy access to the front panel to
check the other 1.1 number out. )
Country of Manufacture : Japan Test
Saample Approx Serial # : ZA9002x
Very Limited Number Made.
Only One Production Run ?? Price Varied Greatly (at least in the
USA).
I don't have any solid
information here, but from what I was told
the NRD-630 was a "one production run" model. Street retail price in
the USA started out at $ 9000. USD, however it quickly dropped below $
5000. USD.
How many that were actually made is unknown, but if the single
production run rumor is true, it sure can't be very many ? Good
thing too as this JRC DSP set was nothing to get excited about for performance as
we will cover in this report below.
Excellent Construction , Direct Keyboard Entry With Excellent Keys, No Feet Included.
As is the tradition with Japan Radio products, the NRD-630 is
beautifully constructed. Heavy gauge aluminum shell with 2 die
cast rack handles. One major difference is that it is not using a
customary mother board with side in computer style boards.
Instead it’s divided up between 4 PC boards of varying
sizes mounted flat on the floor (or roof) of the set. The CPU / DSP and
the RF Unit boards plug directly into the front main microprocessor board. So
no major “spaghetti” bowl of wires to be
found.
If one peers into the innards, it might be said
“Where’s the Beef”? , as it’s DSP light with
fewer components. It came in on our scale at only 12 lbs 10 oz (raw
with no external cabinet). The entire RF section is on the small RF Unit PC board, and that includes the "front end"
preselection filtering too.
The 3 main NRD-630 PC Boards. The "RF UNIT" is on
ONE Small Board / right picture.
You can clearly see the 2 DSP IC's on the CPU / DSP Board upper LEFT corner
/ left picture.
(N9EWO Photo's)
Can be disassembled in seconds
too
with only 4 screws holding the top and another 4 for the bottom.
Just 4 more to remove the front panel from the main body.
If one does not use a additional outer cabinet with the receiver,
the owner will have to add some large stick on feet as the raw
cabinet does not provide any at all. With the 4 bottom cabinet
screws this will be a requirement.
There is a excellent and very quiet switching power supply inside
the receiver as well. This not some after market supply JRC found
laying around either. It’s custom made by a JRC sub-division
(Nagano Japan
Radio Co. Ltd.).
Even the potentiometers are top drawer
using “Tokyo
Cosmos Electric”
controls.
All keys have a very good feel and are similar to ones found on
preceding JRC professional models (NRD-240, NRD-301A etc). These
are not of the “tac switch” membrane variety used with
consumer equipment, so should be robust. They do not have a real
distinctive tactile feedback however.
Direct frequency entry with the keyboard can be entered in MHz
with the decimal or just as kHz without. JRC always does this
right here and with the NRD-630 is no exception.
Oddly there are 2 unmarked dormant buttons found on the front
panel.
It appears that the memories are non volatile, that is not being
back by a battery of some kind (could not verify this) ?
Intermittent Operation With Keyboard Use In Testing.
In testing we did experienced a strange drop out issue.
Using keyboard entry (right after we hit enter) , intermittently
the receiver would go totally silent. , along with the s-meter
going to almost full scale. Was like the RF gain control was turned fully counterclockwise (but
it wasn’t).
Once we keyed in another frequency it would come back to life as
well as the meter. Again it only did this very intermittently, but this is
inexcusable for a close to a $ 9000. professional set.
Very Good Ergonomics and Tuning Knob (Optical) , Channel/MHz
Knob Not Quite As Good Feeling, Good PBT, But No Easy Center
“O”, Notch Filter MIA. “Fiddly” Controls;
Ergonomics are almost at the top of the heap as there are a few
minor bugs that lurk. Some of the controls are touchy and become
a chore to use. For example, the PBT control has no center dimple
on it’s control. One has to watch a LED until it shuts off.
This is a very touchy control and can easily be accidentally left
on.
The RIT is another one that is sensitive to use. The RIT is
adjustable +/- 200 kHz from the tuned frequency, and is toggled
on or off by single button with a led to indicated that it is in
use, this is adjusted using the main tuning knob. There is no
fast way to “zero” this one either, however it can be
zeroed in the user defined functions, but is another chore here
to make happen.
Weighted tuning knob uses a high quality optical encoder and is
one smooth operator. But there is no mechanical resistance
adjustment to help slow it down, so tends to be a bit too smooth.
There are 8 tuning steps available with the tuning knob (1 , 10 ,
100 Hz and 1 , 5 , 9 , 10 and 100 kHz) Up down slewing buttons
just above the knob can be set to one of 4 steps (1, 5 , 9 or 10
kHz) located just above the main knob. You can also slow down the
pulse rate of the main tuning knob encoder in the user defined
functions and this helps with the overly aggressive speed, but
not entirely.
One can be thankful that it does not use a even more touchy VRIT
circuit.
The other larger knob just left of the main tuning is multi
function, and again is used for a quick MHz adjustment, memory
channel selection and also for selecting a group used with
scanning functions, This encoder is not up to the main tuning
knob’s quality, but is OK.
A lock button is provided, and in the user defined functions can
be toggled to work just for the tuning knob or for all other
buttons as well.
Where is the notch filter ? Another feature that found on JRC consumer NRD-545 set but not on this $ 9K professional.
LED Display Top Drawer, 4 Level Dimmer, NRD-93 and NRD-301A’s
Display Whine No Problem Here
Longevity is the name of the game here. The NRD-630 makes use of
LED’s entirely. As we have said in years past, high quality
and properly fed LED’s will outlast any LCD or Fluorescent
device hands down. There is also a excellent 4 level dimmer. Well
chosen steps, with one barely even detectable that’s it on
at all.
The high pitched background display “whine” that
plagued the NRD-93, NRD-301A as tested (and other JRC professional sets over the
years) is totally absent on the 630.
Excellent Switching Power Supply, Cool Operation
As the comment was made above the NRD-630 uses a switching power
supply, it has no power transformer. Mains power can be anything
between 100 to 240 VAC (give or take a bit). No switches to
fiddle with or fuse changes. Also one can power the set with 24
VDC. No 12~13.8 Volt DC input is provided, but being this is a
professional receiver, this was not considered a drawback.
It’s clean too with no buzzes that consumer supplies
commonly give out. The entire receiver runs cool as well.
Like many other professional receivers we see a sub-power switch
on the rear panel. This needs to be turned on before the main
power switch on the front becomes active. The LED in the main
power switch changes from a dim to bright green between stand by
to when the receiver is actually powered up.
Strange AC Power Input Jack Continues. Separate Input
Fuses. Not UL listed.
Just as it was with the NRD-93 and NRD-301A we tested, the NRD-630
continues to use the weird AC and DC input power sockets/plugs.
These are extremely solid and made by the highly respected
Japanese company “Hirose
Electric” (HRS).
They use a metal locking ring
which provides accidental removal, but in a non professional
environment setting, this will make a bit more difficult for a
easy replacement of these cords.
With the tested sample that included a 117 VAC cord, it was only
a 2 wire type. So if one desires a ground connection, there is
large wing nut provided right next to the AC socket.
Another common trait with just about all JRC receivers, we could
not find any UL or CSA listing marked on the rear panel. There
are separate fuse sockets for the AC and DC inputs also found on
the rear panel (see photo below).
Nagano
Japan Radio Co. Ltd
switching Power Supply (left), Hirose
Electric
"strange" AC and DC Power Inputs (right) (N9EWO Photo)
N Type Antenna
Connector
Being Used
The NRD-630 uses a N type antenna connector. While this may be a
requirement for VHF and certainly in the UHF part of the spectrum,
for a HF receiver this is downright weird. So most will have to
purchase a adapter for conversion.
Dual DSP IC’s, More advanced DSP Over The NRD-545.
DSP Overloading Issues.
Two “Analog Devices” DSP IC’s are being
used in the NRD-630. These are a more advanced DSP IC’s that
is used in the NRD-545.
However, there are two DSP overloading issues that very
disconcerting anyway.
The first one is similar to the NRD-545's DSP issues, but not
quite. During nighttime listening conditions with a good antenna (say 49
meter band at night, or any strong signal too even in the 19 mb
during daytime conditions), we experienced a pulsing (popping
sound) signal mixed with broadcast stations. In this case it does
not pulse along with the audio stream. Can be with just a
broadcaster with a dead carrier.
Difference here over the NRD-545 is that when the 10 db
attenuator was engaged (with the pre-amp off) , this issue
totally disappeared. In the case of the NRD-545, it does not cure
the DSP overloading most of the time. So with the NRD-630 this is
more controllable over the NRD-545, but should this DSP
overloading really be there at all at almost $ 9K ?
Second DSP bug is much less important, but for the record. With
extremely STRONG local MW signals, we noticed a stream of
clicking-popping noises in step with the modulation of the signal.
It is not like the NRD-545's overloading sounds.
This was only unearthed this in our extremely intense testing and
really is small potatoes as this gremlin was not detected in any
other part of the spectrum that it covers.
We were able to control this by switching off the pre-amp, or
sometimes adding the 10 db attenuator. But of course this reduces
the sensitivity too.
Sour Audio Quality, Harsh and Excessive Distortion with
SSB Signals, Lousy Internal Speaker. No Synchronous Detection.
A major downside to the NRD-630 lies with audio distortion and
quality in general. Yes, we have excellent audio recovery with
it’s DSP. However it loaded with nasty distortion in SSB
modes. This can be controlled by carefully decreasing the RF Gain
control (and/or the attenuator). The AGC setting still needs to
be in “slow” as well.
AM audio is no great shakes either. Additionally any static is
downright painful to deal with.
A poor front facing internal speaker doesn’t help the sour
pie. The use of a external speaker is a requirement and not a
option. The rear mounted phone speaker jack uses a standard 1/4
inch type.
But even with a better external speaker in use , the audio
quality is just downright tiring (narrow sound). It’s
strictly flat communications quality that makes it
difficult for any quality broadcast listening.
And yes, there is NO Synchronous detection either (double or
selectable sideband). So that cannot be of any help. After about a 20 minute stint we had to turn this receiver off
due to the painful audio ("Brain Pain" in any mode).
The Real Panel of the NRD-630, Uses a N type Antenna Connector. (why a N connector was used on a HF receiver is a good question ?) (N9EWO Photo)
Digital Radiation
Here we find the self generated radiation to be is quite
respectable. On SW is not noticeable at all unless you park
another receiver right on top of the main LED display. And even
here it is minimal.
On MW it’s touch more, but it’s not excessive either.
Using a MW loop nearby should be no problem at all as long as it
sits a foot or 2 away.
300 Memory Channels That Are Easy To Use, Scanning /
Sweeping
For most applications the internal 300 memory channels are more
than adequate. This is 100 more over the Ten Tec RX-340 and 200
over the WJ8711A.
Entry is super easy and access is done turning the left larger
knob. This is excellent in use. The old NDH-95 memory unit (designed in the 1980's) can also be
connected to the NRD-630 as well (not tested).
Scanning up or down of the frequency spectrum or the memory
channels are a dead ringer to the NRD-301A. Both work well.
Noise Blanker OK, But Not Adjustable
Noise blanker function while reducing local power line noise
fairly well, has no other adjustments or settings. It’s
either on or off and that’s it.
Excellent Sensitivity Performance With Pre Amp On, 2 Step
Attenuator
As long as one leaves the 13 db pre-amp engaged, the sensitivity
is excellent. If you operate it in the ruff with no pre-amp, it
seems deaf (just like the Icom IC-R9500).
A 2 step attenuator at 10 and 20 db are provided and necessary
too as covered above (DSP overloading).
Selectivity DSP Sharp, But Not Without A Serious
Limitation
As far as DSP "adjustability" goes with professional receivers (or
non professional for that matter), the NRD-630 falls flat on
it’s face.
It’s sharp enough and does the job for taming adjacent
signals. However, there are only 6 selectivity selections
available and these cannot be changed or any additional added.
In reality there are only 4 that are usable with the lower 2
being useless CW bandwidths . The values are : 0.3 , 0.5 , 1.0 ,
2.7 , 3.0 and 6.0 kHz. JRC’s lower cost NRD-545 is much better here for
versatility ,
and
of course all other professional sets tested on this web site
have a much improved arrangement for selectivity choices.
What happened here is a good question, it just simply is short of
what it should be for a DSP based receiver.
AGC, Fast, Slow and Off, But “That’s All
Folks”
3 AGC selections are available. FAST / SLOW plus OFF. The real
down side is unlike all other professional sets tested, there is
no other adjustment of the decay rate, etc. that can be done, at
all.
It works well enough, however as cover elsewhere in this report,
SSB signals are washed with distortion (even with Slow AGC
properly selected) unless the touchy RF gain control is used.
Good S-Meter Performance, But Just Like on NRD-301A Is
Non Illuminated And No Proper Calibration.
We have a excellent s-meter in the NRD-630. Never pins and is
very linear. The only bug-a-boo that also has been the case with
many other JRC professional sets (including the NRD-92/93, 240,
301A etc), is that the meter is not illuminated. A silly
oversight as even a long lasting bright LED could have been used
here which would have outlasted most other components.
Also continuing the tradition, there is no real calibration
either. Just 0 to 10. One can alternatively select the meter to
show the audio level of any given signal as well.
BITE Feature, Reset Button (Both Internal)
Many professional receivers offer “Built In Test
Equipment” function or otherwise known as BITE. The NRD-630
provides this as well.
It’s not as handy as it could have been as one must remove
the 4 top cover screws and press a small tac button on the DSP PC
board to make happen. This is not covered in the instruction
manual at all.
Once pressed with the receiver on, a series of numbers on the
frequency display will appear followed by “good” if all
is well.
Another internal button right next door to the BITE , is a
“reset”. This does not clear any memory channels or
“User Set Up” functions. It just helps one to get out
of a locked up situation which thankfully we never encountered
other than the intermittent “dead” mode as covered in
the above text.
NOT the Best Choice In A Professional Receiver For Non
Professional Use.
The NRD-630 is one extremely well made receiver. However with
it’s limited DSP functions and lack of features surrounding
this, it’s just does up not make up for the major downfalls.
The nasty audio quality pretty much spoils the pudding to well
steer to another model. Just about any of the other professional
models tested on this web page will more than likely be a better choice and
maybe at a lower cost too. But it will be a hard find on the used
market being very few were ever manufactured.
