Geloso G-258

Description

A three speed (3¾, 1^7/8 and 15/16 ips) half-track tape recorder with a maximum spool size of 5″, the G258 was a perfect ‘office’ recorder with its extremely slow speed ideal for dictation.

Dimensions were 13″ x 8″ x 6″ (330 x 203 x 152mm) and the recorder was priced (in the UK) at 42 gns complete with microphone and 3″ spool of long play tape.

Below is a reproduced test report from Tape Recording Magazine (UK), January 1962

The Geloso G258, a three-speed two-track tape recorder, is priced at 42 guineas and supplied complete with a three-inch spool of long-play tape, spare spool (the maximum spool size is five inches), and a high fidelity microphone. A microphone base suitable for standing on a table, is also supplied.

The recorder is attractively styled in a two-tone plastic case which has an overall size of approximately 13 x 8 x 6 inches. Push-buttons mounted along the right-hand side of the tape deck select Record, Play, Stop or Wind and a toggle switch mounted in front of these, switches the recorder on/off.

To the left of the mains switch are two controls concentrically mounted. The inner one operates for record level or replay volume, and the outer is a tone control on replay only. Mounted in front of the tape deck and in the centre of the recorder is a magic eye recording level indicator, and on the extreme left is a tape position indicator. Just below this on the front of the case is a lever which releases the pressure pads when loading or unloading a tape, by applying slight pressure to this, it works as a “pause control.”

Near the back of the recorder, placed between the two spools is the speed selector which provides for 3¾, 1 and 15/16 ips. This is only the third recorder to be made available in this country with the ultra slow 15/16 ips.

Looking at the recorder from the rear, there are three jack socket connections, one on the left, for a microphone, or radio tuner, etc., and two on the right near the mains inlet socket. The third (marked headphones), is for external speaker or headphones, during replay, and another above, marked ” monitor,” is a high impedance output for headphones which may be used to listen to a recording as it is being made. This is disconnected during replay.

The machine records from left to right using the upper track. By changing over the spools the other track is brought into use. With the tape supplied, the playing time is 1 hour 36 minutes at 3¾ ips, 3 hours, 12 minutes at 1 ips and 6 hours 24 minutes at 15/16 ips. A transparent dust cover protects the tape spools when in use.

With the recorder switched to replay, the circuit is as follows: the output from the head is passed to one half of a 12AX7 double triode after which it is passed through the volume control to the second half of the 12AX7. Following this is half of a second 12AX7 and the signal from this stage is passed on to the output stage, a 6AQ5. Negative feedback is used between the second and third stages to provide frequency compensation. The signal from stage three is also fed to the second half of the second 12AX7 where it is rectified and passed on to the EM84 record level indicator.

The frequency response is compensated at each speed to ensure optimum performance.

When switched to record, the microphone is connected to the input of the first half of the first 12AX7, which remains coupled as before to stage 2 (second half) which now feeds a signal to the record head via a filter network. Bias and erase voltages are obtained from the 6AQ5 which is now working in conjunction with an oscillator coil.

On test a signal of three millivolts at 1kHz was required to fully modulate the tape. The frequency response obtained at each speed is shown in the accompanying graph. Although the slowest speed is intended for speech, some music was recorded from a VHF tuner and on replay the quality was quite suitable for background music, etc. The quality of recordings made at the higher speeds was well up to the standard I would expect from a machine in this class and in fact it is better than some costing more.

No audible wow or flutter was noticed except when sine waves were being recorded to check frequency responses, etc.

Using the microphone supplied, recordings were of good quality, but there was not quite enough gain in hand for any low level work. Most of the time the gain had to be at maximum. However, the microphone, although of low output, is very sensitive and sounds quite a distance away were recorded with excellent quality.

Erasure was complete even on heavy recordings. After erasure the tape noise was just slightly higher than a virgin tape, possibly due to some slight distortion of the bias wave form.

The tape wound evenly at each speed, but braking was not quite as good as I should like. Some slight spilling occurred at times on fast wind. The G258 is simple to use and a neat compact recorder. General standard of workmanship is good and it should prove a reliable unit, the name Geloso may be new to many readers, but they are known for many good quality products, used by radio amateurs the world over.

The G258 is fair value for money and can be recommended.

E. A. RULE