HMV DSR1

Additional Info

By H. Burrell Hadden
from Tape Recording & Hi-Fi Magazine (Fortnightly) 27th January, 1960
THE H.M.V. Tape recorder model DSR 1 is the latest in the line of tape machines made by the E.M.I. Company, and the first to be manufactured in the lower price bracket.
As is well known, this company produces the professional machines used by many recording companies and broadcasting organisations throughout the world, and much of the experience gained in these fields has gone into producing this portable machine for the domestic market.
Because of the lower price range – this machine sells for £50 whereas the professional machines cost £ 500 and more one – might expect that something had to be sacrificed. This is indeed so, but the makers have managed to include a facility that is seldom found in any but professional machines, that of a separate replay head and amplifier so that a recording can be monitored from the tape a fraction of a second after it is made, without the necessity of rewinding the tape.
What then has been sacrificed? Firstly the tape transport mechanism is not of such a high standard as has previously been seen in EMI equipment. The machine has a noticeable flutter, although the wow was quite satisfactory. The flutter appeared to be due to the use of a single ball race on the rubber pinch wheel, instead of two races.
Secondly, the bearings on the capstan flywheel shaft were not as good as I would have liked.
Thirdly, no provision is made for lifting the tape clear of the tape heads during fast wind.
Some minor sacrifices have also been made. The mains lead is by no means long enough.
There is no lead, or even a jack plug supplied for use with the radio input socket.
Having aired most of the deficiencies of this machine, what of its good points?
The separate replay amplifier is a godsend to any serious recordist, as an instant check on balance and quality is always available. It can also be used for producing the echo effects often heard on ” pop ” recordings.
The record and replay heads are of the fine gap type, enabling a good replay frequency response to be obtained. Using the Tape Recording Magazine Test Tape, the replay response at 7½ ips was within ±3dB of the maker’s specifications from 40-10,000 cps and was about 7dB down at. 12,000 cps, 14dB down at 15,000 cps, Hence this machine is capable of giving a very good account of pre-recorded tapes.
Unfortunately the overall record/replay response was not so good. The response was flat within ±3dB between 40 cps and 6,000 cps, but then started to fall, and was -6dB at 10,000 cps, -12 dB at 12,000 cps, and unmeasurable at 15,000 cps.
No attempt was made to find the cause of this loss, and it may indeed have been peculiar to the machine tested.
At 3¾ ips the response again fell off more rapidly than was expected, being flat ±3dB only as far as4,000 cps, and falling rapidly above this to -16dB at 8,000 cps.
The magic eye level indicator is very easy to read, being of the “column” type, and a switch position is provided to enable record levels to be set before the tape is set in motion, avery useful feature. The position indicator is of the digital counter type, and provides an accurate resetting guide.
Tape rewind is accomplished quite quickly, in less than one minute, but the wind is not a very even one-so often the case with a high speed wind.
Signal-to-noise ratio was quite adequate, and there appeared to be sufficient record gain to use a low level microphone, although this necessitated turning up the record level control almost to full.
A tone control, top cut, is provided for use with the internal amplifier and Ioudspeaker, but this is inoperative when the quality amplifier output is used. The replay amplifier can be used as a straight through amplifier by feeding a signal in at the quality output jack, and the response obtained in this way is excellent.
A safety locking device is incorporated in the record switch to prevent inadvertent erasure of a recording, and there is also safety interlocking between the fast and the normal speed controls.
The microphone supplied is a crystal type which gives fairly good results.
The operating manual contains some excellent advice concerning the regular cleaning of the tape heads. Unfortunately this cannot be done without removing the plastic cover and the control knobs. If a suitable Allen key were supplied with the machine, such a maintenance session would be much simpler.
To sum up, in spite of the objections above this is a machine worth buying if the separate replay facilities are desired, but it is to be hoped that the EMI Company will soon produce a machine, say in the £80 bracket, in which fewer compromises would need to be made to keep the price down.
We look to them to be leaders in this domestic field as indeed they are in the professional side of the industry.
MANUFACTURER’S SPECIFICATION
Voltage: 200-250 A.C. only.
Consumption : maximum 95 watts in record position.
Size : 15¼ x 14½ x 7½ in.
Tape Speeds: 7½ and 3¾ ips.
Wow and flutter: 0.3 per cent.
Maximum spool size : 7 in.
Frequency response : 50-10,000 cps ±3dB at 7½ ips.
40-12,000 cps ±5dB.
Bias frequency: 65,000 cps approx.
Input sensitivity: 3mV. across 500 Kohms.
Outputs: C.C.I.R. corrected to feed external amplifier. 100 mV. across 200 Kohms. External loudspeaker jack which,
when in use, mutes internal loudspeaker. Output to match 3-5 ohms.
Valves: 6BR8, 12AX7, EL84, ECL82, EM84, two diodes, C3B, bridge rectifier.
Signal-to-noise ratio : ±45dB.
Construction : separate record and playback amplifiers, plus three-head system allowing virtually instantaneous playback of recorded signal. Solenoid operated servo brakes. Pause control giving instantaneous stop-start.
The DSRI is supplied with a spare spool and a 1,200 ft. reel of tape carrying a selection of special demonstration recordings.