Thorens TD 115 MkII Turntable Review

The Thorens TD 115 MkII semiautomatic turntable, which replaces the company’s Model TD 115 at no change in price, is basically identical to its predecessor, with the addition of the 78-rpm speed to the 33-1/3- and 45-rpm ones. The nearly 3-pound cast zinc-alloy platter is belt-driven by a servo-controlled d.c. motor whose tachometer feedback is designed to maintain correct speed under load changes as well as line-voltage shifts.

The low-mass Thorens tone arm is a straight tubular design in which the entire arm tube (or “wand”) unplugs for changing cartridges, unlike the usual plug-in shell arrangement. One plug-in wand is supplied with the turntable. The threaded counterweight is mounted unconventionally on a bracket extending to the rear of the tone-arm pivots with the weight facing the front of the arm instead of its rear. The weight, being asymmetrical in its mass distribution, can be reversed for balancing heavy cartridges. Its adjustable stylus-force scale is not calibrated numerically but has different-thickness lines and dots to indicate force settings from 0 to 3 grams at intervals of 0.25 gram. An antiskating adjustment scale surrounds the base of the arm.

The TD 115 MkII is operated by three flat slider plates on its upper front surface.

One turns on the power and selects the speeds (33-1/3 rpm when moved to the right of its center off position, 45 rpm to the left). For 78-rpm operation, the slider is moved to the extreme left by pressing in a small button that normally limits such movement.

Although the unit is powered, the platter will not turn until a second plate is moved either right or left. If moved left (m) the motor is turned on, but the automatic arm lift is disabled, making the TD 115 MkII a fully manual player. If moved right (start) the player must still be cued manually, but at the end of a record the arm lifts and the motor shuts off.

The remaining control is the arm-lift cueing control. It is clearly marked to show the pickup position (up or down) but will not latch into its “down” setting unless the turntable has been switched on and put into motion. Shutting off the turntable manually returns the lift plate to its “up” setting and raises the arm.

A small knurled wheel, flush with the top of the control panel, provides a vernier speed adjustment for the turntable. The edge of the platter has two sets of rear-illuminated cast stroboscope holes for the 33-1/3-rpm speed, with either 50- or 60-Hz power sources. Although no holes are provided for the other speeds, they are correct when the 33-1/3 pattern is stationary.

The turntable and arm are mounted as a single unit on a rigid plate that is suspended on soft springs from the record-player base.

Laboratory Measurements

Our test sample of the Thorens TD 115 MkII was furnished with a Shure V-15 Type IV cartridge mounted in its tone-arm wand, and we did our testing with that cartridge. Examination of the mounting instructions indicates that the cartridge-mounting process has been considerably simplified from the rather awkward procedure used on early low-mass Thorens tone arms. Since the magnetic antiskating compensation cannot be removed completely (the scale does not go to zero), the arm tends to drift outward when balanced, thus complicating the initial setup adjustment. With care in balancing, we found that the tracking force was within 0.2 gram of the indicated value, and when the arm was originally set to be accurate at 1 gram with an external gauge the error was less than 0.1 gram at any other setting. The effective arm mass was just under 7 grams (less cartridge and hardware), and with the Shure cartridge the arm resonated at 10 to 12 Hz, an ideal frequency range.

The tracking error was less than 0.5 degree per inch of radius over a 12-inch record surface and close to zero at most parts of the disc. The antiskating calibration, consisting of arbitrary numbers from 1 to 7, requires a reference to the manual for the correct setting (which is a function of the stylus shape as well as the vertical force). It proved to be quite accurate when set according to instructions. The cueing system was not only very smooth and without any tendency to jar the arm, but it was unaffected by the antiskating torque and returned the stylus to within one rotation of the point from which it was raised. The capacitance to ground in each channel of the tone-arm output wiring was 215 picofarads, which is compatible with the load requirements of most good cartridges.

The turntable speed was exactly 33-1/3 rpm when the stroboscope marks were stationary, and it could be adjusted over a range of +8.7 to —7.5 per cent. When set exactly to 33 V3 rpm, it was also exact at 45 rpm, though it ran an easily correctable 2 per cent slow at 78 rpm. The speed did not change detectably with line-voltage variations from 80 to 140 volts, nor did it drift from a cold start over several hours.

The turntable flutter was 0.08 per cent in a DIN measurement and ±0.08 per cent weighted peak (CCIR). The flutter frequency spectrum was principally at 5 and 10 Hz, with a small component at 15 Hz. The rumble was —37 dB unweighted and — 63 dB with ARLL weighting, both of which represent excellent performance. The rumble spectrum was largely random, with small but detectable peaks at 7 and 30 Hz.

The isolation from the mounting surface afforded by the turntable suspension was good, with most of the transmission taking place below 80 Hz. Since the operating controls are on the base portion of the unit and therefore isolated from the platter and tone arm, there is no tendency for control operation to jar the arm or transmit noises through the system.

Comment

The performance of the TD 115 MkII is absolutely first-rate, and its low-mass tone arm allows the full benefit of today’s high-compliance cartridges to be realized without introducing tracking problems with warped discs (we have seen very few that were not warped to some degree). This is also one of the very few turntables with full manual operation, free of the annoyance of having the tone-arm trip mechanism operate when one is trying to cue to an inner groove of a record. According to Thorens, internal logic circuits prevent the arm lift of the TD 115 MkII from operating during manual cueing, but they let it respond to the run-out groove at the end of a record. Fully manual cueing was possible (necessary, in fact) in the M mode of operation. However, when we used the semi-automatic operating mode the arm lift tripped if we tried to move the arm to the inner part of a disc. Over most of the surface, manual cueing could be used in either mode.

This is a fine record player with all the inherent quality that has earned Thorens its reputation among discerning audiophiles. A minor criticism is that the operating controls, though located on the front edge of the unit, are inaccessible with the cover lowered. Although the TD-115 MkII is not exactly inexpensive, it is at least affordable by anyone who is seriously interested in playing records (including old 78s) with a minimum of compromise. It is also one of the few examples we have seen in which an existing product has been improved (in this case, by the addition of the third speed) with no change in price.

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