MUSIC FROM MANY COUNTRIES
by wireless with
TELEFUNKEN 40
Long range All-Electric receiver with
station
selector for use with or lighting
-batteries
mains.
with TELEFUNKEN
LOUDSPEAKER
ARCOPHON
HONG KONG DAILY PRESS, THURSDAY, FEBRUARY 26, 1931.
RADIO
For Demonstration and further particulars apply to : SIEMENS CHINA CO.
TELE FUN KEN
Office-Pedder Building, 4th Floor.. Showroom-27, Nathan Road, Kowloon.
Canton Office- Shameen.
Bwatow
-Gebr. Roese,
TELEFUNKEN
LONGEST · EXPERIENCE-LATEST DESIGN.
ARCTURUS
The Famous Blue Tubes
For Better Radio ReceptionTM
Exclusive Features:-
LIFE-LIKE TONE.When you purchased your radio set, you expected to get clear, life-like reception, That depends on the tubes you use! The exclusive, advanced design of Arcturus Tubes eliminates mechanical background noises-every note, every word, comes in with a vivid Life-Like Tone. With a complete set of Arcturus Tubes in your radio, you know you'll get unusually clear, brilliant programmes. 7 SECOND ACTION Arcturus Blue Tubes in your radio set bring in programmes in just 7 seconds. no annoying wait for programmes to begin. Just flip the switch, and by the time you turn the dial, the programine is there-quick, certain, as compared to the usual 30 seconds, or more, walt
WORLD'S RECORDS FOR LONG LIFE.- Throughout the world," Arcturus: Blue Tubes are proving themselves to be the tubes that have established a world's record for long life. Hecause?" they withstand exceptional overloads that often burni out other tubes. Arcturus Blue Tubes assure the user of long, satisfactory service.
Ask Us For Demonstration
THE SINGERE CO, LT
DÍSTRIBUTORS,
FEATURES
GETTING THE BEST FROM YOUR LOUD-SPEAKER.
THE IMPORTANT LAST LINK.
ACCENTUATING TREBLE OR BASS.
Listeners divide themselves into of clean-ént high notes; this lend- two classes: those who listen to speaker working with a cone that incal stations and those who tog tends to be low-pitched, is a BUT- distant stations. The local listener prisingly, good asset to quality. soon becentes critical of the repro- dugtion given by the load-speaker. Whatever the type of loud-speaker in use, the question arises: An I getting the best from it 1
Валеб.
The position of the loud-speaker has a bearing on the quality of reproduction. Different positions in the room should be tried, before Perhaps, the land-speaker is low finally fixing the loud-speaker.. pitched and Booms certain Cone loud speakers that appear to notes, That means that the free deficient in bass can often be quency response of the top notes is improved by mounting the cone weak, so that the low, notes are behind a balle board. Attractive accentuated and that certain low baffle boards are now available in
reproduced by the wood and metal, loud-speaker at disproportionate | prices. strength. To overoume this, fault! one can use a pentode power valve, which tends to accentuate the high
note# are
notes.
On the other hand, some loud. speakers are high-pitched, and while they give clear and crisp
at moderate
Before finally deciding that the best is being obtained from the foud-speaker whatever its type, the listener should make sure that the set is offering the loud-speaker every chance to do itself justice.
Output Arrangements.
reproduction of speech, they are Many sets fail to give a plens
"
apt to sound shrill during the ring tone because the output-ar
One can production of music.
rangements connecting the last counteract the absence of base-note | valve with the speaker are not so reproduction by modifying the am- good as they should be.--
lifer. But not many lifeners would be prepired to do this. Fixed condensers up to .003 micro Farad can be shunted across the load-speaker winding to accentuate
nss notes.
The Most Popular Type. The averag: loud-speaker in use ́to-day is a balanced-armature cone, This is by no means the only good type. But one can understand ita popularity, for considerable power
Indeed, tibiseurprising how many amateurs one meets who are constantly arguing the respective merits of various new super power valves and low-frequency couplings, and the merits and demerits of moving coil and dynamic speakers, and yet they do not get good ru suits because the output arrange- ments are wrong.
If the set overloads and gives a reedy" tone then. it is quite pro bable that a larger power valve is called for.. The existing valve may have an impedance of 9,000 nr 10,000 ohms and bo, eapable of standing. ap to a relatively small grid swing. A larger valve is fitt ed having perhaps an impedance of 2,000 or 3,000 chris and a much greater grid swing, provided that it is given sufficient grid bias--at last 12 or 15 volts-and 120 volts high tension.
Anode and Grid Voltage.
Many users of three new power valres do not give ulicient anode and grid volt, and good results are hardly to expected under incorrect But crea operating conditions. when the valve is operating on the cerrect part of its curve, with an- ple grid bias and high-tension, the. trao may not be satisfactory. It may be excessively boomy in plen of the former excessive reediness And because the sepaker rattles at the slightest overload, the set an a whole may still appear to suffering from overloading. nine cases out of ten this is becaus oper arrangements have not been made fur output transformatica from the anode circuit of the power' valve to the speaker windings.
ใค
En
The two important reasons why necessary are, first that the filter, if properly arranged, matches up the impedance of the speaker to that of the anode circuit, and, ee cond, that the comparatively heavy anode current flowing in the power valve circuit is prevented from passing through the speaker wind. ings.
(Continued on. Page 3.)
output filter of some kind is
can be handled without rattling the HAVE YOU HEARD THESE?
wait. Balanced, armaturs loud- speakers are not critical as regards the power valve, As most units
are of high resistance, ʼn valve of 3,000 ohms. or less is suitable.
The moving ruil is ons of the most perfect forms of loud-speaker, but to get good results one must have a good set. A really efficient moving-coil, laud-speaker responds equally well to high and low notes, but any deficiency in the frequency response of the amplier shows up very badly. The greatest disadvantage of the moving coil, namely, the need for an accumula- lor or mains supply to energise it, has been overcome by the produc tion of the permanent-magnet moving-coil speaker.
The New Inductor.
Here are lists' of long-wave and short-wave stations which should be picked up by anyone in Hong Kong who has a mode... rately good set suitable for re- ceiving such signals. Success in picking up these stations also depends very largely upon lay- ourable atmospheric conditions. Readers are invited to add to this list should they succeed in picking up any station not in- cluded in either of these lists.
AC-SG3 Set
ENTIRELY MAINS OPERATED
A sensation in 3 valve sets, with 1 watt undistorted output; enough power for any moving coil or dynamic loudspeaker. A set that will appeal to you whether you are interested in perfect quality from the local station or clear reception from distant stationa,
Price only $145.00
Inolading Mazda Valves (the best Brush Valves)
Special B ELIMINATOR for any domestic set or made to order for any requirements.
For
use
perfect reception
MAZDA? Valves,
large stock newly arrived
RADIO batteries made by new process minimis- ing deterioration "PERTRIX" 150, 100, 60, 45 volts and C. batteries,
"TROLIT" and Pressed Fibre Panels
Ebonite "TRO
cut in any size. Loudspeakers, and various parts are also obtainable.
For further information apply to
CANTON TRADING ASSOCIATION, LTD.
CHINA BUILDING (5TH FLOOR).
LONG-WAVE STATIONS.
Wave length (Metres) Station
200 Manila
Call Kilo- Siga cycle K.2.1.R. 1,153
K.S.M.H. 1,025
EVERYTHING
1,030
277 Shanghai 280 Tientsia 310 Shanghai 320 Feping
C.R.C.
K.R.C. C.O.P.E 945
345. Tokyo J.O.A.K. 353 Hiroshima J.O.F.K. 35% Hong Kong Z.B.W. 357 Bombay V.U.B. 361 Sapporo 306 Keljo. 370 Nagoya 370.4 Calcutta
650
846
840
J.O.LK, 830 J.O.D.E. 820 J.O.C.K. 810 V.U.C B09.9 380 Kumamoto JO.G.K, 790 J.O.H.K. 770 700 J.D.A.K. V.U.R. 764 J.O.B.K. *760 C.M.B. 729 KZ.B.M.
390 Sendai
395 Dairca
308 Rangoon -
400 Osaka
'410 Canton
413 Manila
**SHORT-WAVE STATIONS.
STATION
Call Brok
A variation of the moving-coil principle is the inductor-dynamic loud-speaker. The coil is replaced by a special armature system. The arniature is suspended in a magne. C7.85 Dobintz (Germany)
0013 Khalarovak (Bus).1.97. tic-field-and-moves-backwards and 66.7 Naue forward horizontally in the gap provided. This new loudspeaker is a strong rival to the moving coil. It works well with any set of aver- age, efficiency.
CTYLES
Tx (Howa Kowo)
OF WORKING
4,484 Me, Wel & Fri, 6 p.z. & 3 a.m.
5.201 Nor regular
5,000 Thin; Thum; Sat, 8 pan;-
3,890 Bunday midnight
7,142 | Daily 6.30 p., & 11 p..
7,310 Not regular
7.750 Dally 11 p.m.
8,108 Tuba. Vrl,9 pt-1 D.
9,230 Not regular
0,008 Not regular
A.F.H.
1990 6-10 p.m.
A.0.3.
50.
48,6
41.3
BEGLOW Kame Porth Bingapore
B.F.N.
1.M,A.
U.A.G.
V.B.J.A.B,
38.8
37.
Kootwijk (Holland) Bangkok (Blam)
P.C.L.
HS4PJ.
5.
By Lany
2.B.L.
31,55 Melbourne
3,0,0.
81.48 Bebeaoctady
810 Eindhoven (Holland) 11.28 Sranny
P.C.J,
Z.F.D.
81. 28.5
Nairobi (Kenya).
7.1.0.
Bydrey
ME
16,526 | Not regular
B
Bandsong Cholmsford (England)
F.L'E 5.8.W.
WAKO.
For those listeners desiring crisp and clear reproduction of speech, the linen diaphragm, driven by a balanced-armature movement, is
25.53 ideal; and the best models are. also capable of giving very fine quality of reproduction of music.
If the listener has more than one loud-speaker, it is a good plan to try working them together. Then if one accentuates, the hass, notés and the other the high notes, the.
tremely satisfying, The old-fashion- ed horn-type loud-speaker has yet to be beaten for the reproduction
34.5 Manila 28.35 Behenectady. 1888 Bandoeng 18.4 Kootwijk (Holland)
Bandoong 174 10.0 Bangkok 13.8
Heotwijk (Holland)
15.74 Bendoang IBA
Nancy (France)
13.98 Pittsburg
W.ZXA.F. 9,600 Dally am.'
P.L.G.
P.C.J
P.L.T.
0,620 Fri, 3 km., Set. 2 am, '& 10 am."
0,600 Not regalar
5,677 Midnight daily
11,000 Midnight-la.m. daily
11,751 7,80 p.m. & 1a.m. daily, except
12,240 Nightly
Saturday and Sunday
12,850 1am. Wod, Fri., Bab.
10,102 Daily 580 p.m. to midnight 10,304 Daily 7 7.
17.250 Daily 8 p.m. to midnight
11.6.1.P.3.17,751 Sundays 7 pm. & midnight-
18,404 Each afternoon
18,220. Daily 130-7 pm.
P.C.E.
P.L.E.
19,851 Daily 8
W.6.X.K,
1,40 | Not regular
[Allowance must be made for summer-time in most, Eur pean countries, which is one hour ahead of true time.]
TELEPHONE 24610;
G.E.C.) ELECTRICAL
your guarantee
COSIER FIRES
FOR COSY HOMES
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An example from the
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3