keisuke kuwata Acoustic Revolution Live at Nissin Power Station 1991.3.26

Full Size Can: Shure SRH-840 Professional Monitoring Headphones.

Designed for professional audio engineers and musicians, the SRH840 Professional Monitoring Headphones from Shure are optimized for studio recording and critical listening. A precisely tailored frequency response and 40mm neodymium dynamic drivers combine with total comfort and durability to provide the ultimate listening experience. The replaceable cable and included set of replacement ear pads ensure a long-lasting lifetime of use. Also includes threaded 1/4" (6.3mm) gold-plated adapter.

Features (Manufacturer's hype):

• Precisely tailored frequency response delivers rich bass, clear mid-range and extended highs.

• Wide, padded headband provides ergonomic fit for superior comfort over extended periods.

• Closed-back, circumaural design rests comfortably over the ears and reduces background noise.

• Collapsible design for easy storage and portability.

• Legendary Shure quality to withstand the rigors of everyday use

• Bayonet Clip securely locks cable into ear cup.

• Replaceable ear cup pads included to ensure long product life.

• 3m (10ft) coiled detachable cable provides plenty of length and easy storage and replacement.

• Carrying bag protects headphones when on the go or not in use.

Specifications:

Transducer type
Dynamic neodymium magnet

Driver size
40 mm

Sensitivity (1kHz)
102 dB/mW

Impedance (1kHz)
44 Ω

Max. input power (1kHz)
1000 mW

Frequency range
5 Hz - 25 kHz

Net weight (without cable)
0.7 lb (317.5 g)

Shipping weight
1.75 lbs (794 g)

Length of cable
3 meters (9.84 ft)

Type of cable
Detachable coiled oxygen-free copper

Plug
Gold-plated 1/8" (3.5 mm) stereo mini jack

Un-boxing and first impressions:

The box is well designed and made and printed in English and Japanese, it appears that Shure have intentions to make an impact on the Japanese market with this product. The extra ear pads are a nice touch. The headphones come with the usual standard leatherite pouch, a detachable cable (nice touch) and the standard gold plated adapter plug. Although this is a shure product it is only designed in USA and the headphones are made in China.


The manual is multi-lingual and easy enough to understand. The build of the headphone has a solid feel and does not feel flimsy.

Listening has not been executed yet and this will be done later with my Opera Consonance Cyber-30 (2A3 tube) headphone amplifier connected to the Elekit CD player. But I have already been advised by the supplier that these headphones will require 150 hours of burn in before they reach their full potential.

Japanese book on the story of Collins Radio Equipment

CQ Publishing - Japanese book on the story of Collins Radio Equipment

339 pages / 9.2 inches
Written in Japanese
Publication : 2006

I just purchased this book, although in Japanese it does have allot of photographs and circuit diagrams which are extremely useful. This is also a bit of a collectors item as it is quite rare to be found outside Japan.

Rockwell Collins HF-80 Station

Rockwell Collins HF-80 Station Consisting of HF-8054 Receiver, HF-8010 Exciter & HF-8090 Controller. Manufactured in the 1980s. Utilised by Embassies, Armed Forces & Government Departments.

My Rockwell Collins "Pro Mark" KWM-380 (S/N: 926)

I am the proud owner of a KWM-380 serial no. 926. This is a revolutionary transceiver made by Rockwell Collins some 30 years ago and is in very high demand even today on the secondhand market. They are no longer in production. Speculation on the no. of production units still exists but it is agreed that the figure is somewhere between 2,500 to 3,000 units ever to be produced. The unit price during the production day was in the region of US$6,500 a unit and they can fetch between US$2,500 to US$5,000 today secondhand dependant on the unit configuration. This is a radio that I am unlikely to part with. I am also a member of the Collins Radio Association. To the best of my knowledge this is the only Rockwell Collins KWM-380 in existence in Hong Kong.

It has the Kiron modification and has two optional filters...the 1.7khz SSB and 360 hz CW filter. The case as you can see is in excellent condition.

The Rockwell Collins KWM380 (One of the finest transceivers ever built).

KWM-380 SPECIFICATIONS

Parameter Specifications

Physical
Size 394 mm (15.5 in.) wide; 190 mm (7.5 in.) high,
inc. 25 mm (1 in.) feet; 457 mm (18.0 in.) deep.

Weight 27.2 kg (50 Lb.), max

Environmental
Operating temperature 0 to 50øC (32 to 122øF)
Operating humidity 0 to 90% relative humidity
Operating altitude 0 to 3049 m (0 to 10,000 ft.)
Vibration 2 g's, 10 to 33 Hz

Electrical
Primary power Strappable for: 105,115,125/210, 220, 230, 240,
250 V + 5%, 50 to 60 Hz; or 12 to 15 V dc,
negative ground:120 watts max in receive,
600 watts max in transmit

Receiver
Frequency 0.5 to 30.0 MHz, tunable in 10 Hz steps

Modes u.s.b., l.s.b., a.m..and c.w.

Sensitivity (Soft uV 0.5 pV or better for 10 dB (s+n)/n, 2.0 to 30.0 MHz,
measurement) s.s.b. and c.w.; 1.0 uV or better for 1.8 to 2.0 MHz.

Selectivity (3 dB Selectable:
bandwidth) 8 kHz *1.7 kHz
*6 kHz *360 Hz
2.1 kHz *140 Hz
*Optional Filters

I.F. and image rej Greater than 60 dB

Intermod distortion -50 dB or better for two signals of -10 db mW each,
20 kHz apart

AGC Audio output variation not more than 8 dB for 4 uV to
200 mV open circuit r.f. input variation

Audio output Not less than 3 W into 4 ohm load, at 1 kHz, at not
more than 10% total harmonic distortion
Line audio output not less than -10 dB mW nominal in
to 600 ohms
Frequency response: 300 to 2400 Hz with not more than
5 dB variation
Transmitter
Frequency 160 through 10 m amateur bands, in 10 Hz steps
160 m 1.800 to 2.000 MHz
80/75 m 3.500 to 4.000 MHz
40 m 7.000 to 7.300 MHz
20 m 14.000 to 14.350 MHz
15 m 21.000 to 21.450 MHz
10 m 28.000 to 29.700 MHz

Modes u.s.b., l.s.b., and c w. (RTTY by AFSK on l.s.b.)

Output power 90 W pep, min (100 W, nominal)
In c.w. or RTTY: 50% duty cycle; key down 15 minutes,
max. Automatic turndown to 50 W after 10 seconds.
With optional blower kit installed, power is 100 W
average, 50% duty cycle, key down 1 hour max at 25øC;
30 minutes max at 50ø C for all modes.

Unwanted sig suppression
Carrier -50 dB or better
Undesired sideband,
1 kHz ref -55 dB or better
Harmonics (all) -40 dB or better
Mixer products -50 dB or better
Third order distortion 25 dB below each tone of 2-tone test

Synthesizer accuracy Accuracy within + 5 Hz after 10 minutes warmup when
and stability 39.6 MHz and 455 kHz oscillators are set to within
+/- 3 Hz.
Stability within +150 Hz over temperature range of 0
to 50øC (32 to 122øF) if oscillator's set within
10 Hz at 25 øC (77 øF)

Antenna Impedance 50 ohms, nonreactive. (Full transmitter power output
with v.s.w.r. of 2:1 or less. Automatic power output
turndown with v.s.w.r. greater than 2:1.)

Audio inputs
Microphone Low or high impedance, dynamic; 3.3k nominal
impedance

Line 600 ohm, unbalanced; 40 mV input sufficient for full
r.f. power output

Fast Trains.

Bee Gees.

3D Virtual Reality Tour of Hong Kong Science Park.

The following is a 3D virtual reality tour of Hong Kong Science Park - the place I work at. I am the Chief Manager of Facilities Management Services of the Park. Click on HQ to enjoy better video and sound quality, enjoy!