[GP49000]

In the late 1970s, Garrard, its sales in decline as the Unimech record changers proved to be a poor replacement for the Autoslim models, weak in the budget market while unable to perform at the level expected in the entry and midlevel hi-fi market, worked on its last "new" design, the two-speed, belt-drive "Large Delglide" series of automatic turntables. Even this wasn't ALL new; as in the small Delglides, its modular mechanism was redesigned from that of the GT55 models.

Garrard was, by now, committed to the concept of the automatic mechanism as an integrated module. It was less costly to assemble at small-scale facilities instead of on a big, expensive assembly line. The module in the GT55 and the Delglides was an advance on that of the CC10 minichanger and the Unimechs, in that nearly all its mechanical parts were made of low-friction DuPont Delrin® plastic instead of metal stampings, the entire module designed to need no lubrication or maintenance over its entire service life.

The module was mounted directly underneath the pickup arm and was driven from a gear on the center of the platter by a cogged belt. On the large Delglides, separate control subassemblies were outboard of the module, mounted on a full-sized moulded plastic top plate that formed the upper half of the "plinth." The control subassemblies had low-force knobs with steel spring wires actuating the working parts on the modular mechanism. The plastic top plate was mounted on a wooden frame that formed the lower half of the plinth. A fibreboard bottom plate finished off the assembly.

The large Delglide models included fully automatic units with single-record and multiple record-changing capabilities; single-play units requiring the user to set down the tonearm by hand, with automatic end-of-side arm lift/return and shutoff; and a full manual model with manual tonearm setdown and lift. All models had a manual tonearm lift-lower cueing control that was completely separate of the modular mechanism, being operated by a lever controlling a fluid-damped arm-lifting shaft. The modular mechanism itself differed among the different models, with parts removed from the full-automatic record changer version to provide progressively lesser levels of automation. Since the automatic record changer was fast fading in popularity, this allowed Garrard to tailor the design to suit the changing market. The automatic mechanisms themselves performed with impressive smoothness and quietness, without the clicking, snapping and creaking noises often found in earlier automatic turntable mechanisms.

Two motors were used in the belt-drive Delglide series: the lower-priced units had a four-pole induction/synchronous motor identical in principle of operation to the Garrard Synchro-Lab® motor, but not built by Garrard; it was sourced from Matsushita, one of several turntable companies which had licensed Garrard's patent on the induction/synchronous design for their own production. The motor in the top-line models was the permanent-magnet DC motor with electronic servo speed governor circuit from the GT55, the motor also produced by Matsushita, and the electronics built in England in Plessey facilities from the Matsushita design.

The induction/synchronous motor provided good performance. Speed was changed by shifting the position of the belt on a stepped motor pulley; on fully automatic models this also changed the setdown position for the tonearm: 12" for 33 1/3 rpm, 7" for 45 rpm. As in any other belt-drive turntable without a variable speed control, absolute speed accuracy depended on the belt being in good condition and of the proper thickness. Garrard belts were excellent in this regard; I always found speed with a new, genuine Garrard belt to be within 0.3% of nominal. The DC motor with servo control provided slightly lower vibration for a slightly better rumble specification. It was also lower in torque, though this wasn't apparent in normal use due to the electronic speed governor. User-accessible speed adjustment was provided, with a 6% adjustment range; if a belt was fitted that differed in thickness, screwdriver adjustments on the circuit board could be used to bring the 6% adjustment range to the proper ±3%. However, the governor circuit proved to be subject to aging of its components, particularly the electrolytic capacitors. As in the GT55, speed instability would develop and owners junked many units instead of having them repaired. Now, decades after their construction, it is recommended that any of these belt-drive models with the DC servo motor and governor have all the electrolytic capacitors replaced; there are about a dozen, but they are inexpensive parts. I have sold several GT55 and GT35 (and Matsushita-Technics) units acquired as "non-operational" at junk prices, after restoration in just this manner.

The tonearm system of the large Delglides was an excellent one. As in the Unimech subchassis, the horizontal pivot bearings for the tonearm are integral in the modular mechanism. But unlike the Unimech's bearing, which was a crude axle-in-hole with the pivot shaft resting on a spring-loaded ball thrust, the Delglides had an extremely low-friction, sealed ball-bearing assembly sourced from an outside vendor specializing in precision bearings. The tonearms themselves were S-shaped with the standard SME-type bayonet fitting. For vertical motion, they had precision jewelled bearings suspended on preloaded needle pivots mounted in a gimbal-shaped ring. The dynamic mass of the tonearms was reduced to accommodate extremely high-compliance cartridges by a new headshell, the H-1 made of magnesium with a deep "skirt" to provide rigidity. This headshell was among the best ever made for S-shaped tonearms with standard fittings, but its material does tend to take on a dull appearance with age. Tracking weight was controlled by a calibrated counterweight; antiskate was provided by a spring mechanism mounted below the deckplate and controlled by a knob with dual calibrations adjacent to the tonearm base.

Unlike the small Delglides, the large models were supplied only as integrated record players mounted on plinths and dust covers. None were made available as bare chassis for installation in cabinets. Model numbers began at GT20, just above the small Delglides which left off at GT15. Where higher model numbers of the small Delglides represented higher performance tonearms and heavier platters with the same level of automation, those of the large Delglides varied with automatic capabilities, while the platters and tonearms were all essentially the same except for the stroboscopic markings on the GT35 models.

The GT20 was the basic, no-frills version of this series. It had the four-pole, induction/synchronous motor. Its operational controls were only a speed selector, on/off switch and the tonearm lift/lower lever. Being fully-manual it lacked any automatic mechanism at all, having only a tonearm base housing underneath.

The GT25P added automatic tonearm lift at the end of side, automatic tonearm lift in mid-record by means of a REJECT control, and automatic shutoff at end of play. It retained the four-pole, induction/synchronous motor.

The GT35P added the DC motor, electronic servo governor, and speed adjustment to the GT25P. Stroboscope markings on the turntable platter and an LED strobe illuminator were provided for accuracy in adjusting speed.

The GT25 was the fully automatic version of the GT25P, with single record and multiple record-changing capabilities. For multiple record-changing, a tall record spindle would be exchanged for the short manual spindle, and the record stack would be stabilized on a record support platform at the right rear of the turntable unit. It retained the four-pole, induction/synchronous motor and because it had automatic start and tonearm setdown, added a record size selector with 7" and 12" positions, separate from its speed selector.

The GT35 was the fully automatic version of the GT35P, with single record and multiple record changing capabilities as in the GT25; the DC motor and electronic speed governor, speed control and stroboscopic turntable with LED illuminator. Its record size selection was linked to its speed selection: 7" for 45rpm, 12" for 33 1/3 rpm.

The GT25 and GT35 models had ball-race thrust bearings for their platters, due to the need to accommodate a record-changer spindle. The GT20 and the "P" models had a single ball thrust atop a fixed centre shaft, and a thrust pad in the platter.

Conspicuously absent from the large Delglide series was the direct-drive motor. The Garrard DD75 remained, for a time, the only direct-drive Garrard turntable, as the excellent Matsushita direct-drive motor could not be used with the cog-belt drive for the modular mechanism. Later models would combine the modular mechanism with a new, Garrard-built direct-drive motor.

Photos:

GT20. Only two controls: speed selector at left, and On/Off at right.
GT20 tonearm...the same arm as used in the entire series.
GT20 underside, note lack of auto mechanism compared to GT-35 in later post
GT20 control panel: only an on/off switch. This is actually a GT20-1, about which more later.