Birth of the Loricraft 501

The inspiration behind the Inspiration.

By Nigel Pearson Chief Design Engineer Loricraft Audio

In 1990, or thereabouts, we started to look at the possibility of putting the Garrard 301 back into production. We took advice from the last managing director of Garrard and Mr. Brian Mortimer whose father designed the 301. Brian was chief of quality control at Garrard.

An estimate of £500,000 was thought to be a minimum, which at today's value would be £1,000,000 to restart. Doubtless making the product in smaller quantities would be less expensive but the cost per machine would have been too high. Taking this to its logical conclusion, we thought of Garrard 501 and improved this version.

The first research was to find out why the 301 and 401 sounded as they do. Two hypotheses came forward, one positive, one negative. The positive: that the idler wheel principle produced the dynamic sound, the negative: that the higher than now typical levels of rumble of the 301 produce vibrato. The second hypothesis seemed the more likely not least because the more humble Garrard SP25 and LAB 80 have excellent dynamics, although obviously inferior to modem decks in most other respects. If the Garrard 501 proves anything, it is that the idler system is the reason and not the vibrato, as 501 has less rumble than any Garrard idler design.         .

Why don't others build idler drives?

Simply, idler drives are expensive and difficult to get right. A belt drive system should be at least a factor of 10 cheaper to produce. It is almost impossible to make a bad belt drive design. This being true why do bad belt drive turntables exist? The answer is likely to be the need for something unique. Also the looks may take over. The worst thing is there is now a lot of folklore that sometimes creates fixed thinking.

The folklore has it that a belt drive should be a flywheel supplied by just enough power to overcome friction. This being the case, reduces friction to a minimum. The motor is decoupled from a flywheel so as to minimize the transmission of vibration from the motor to the record surface. These principles are undeniably correct so what is it that goes wrong? For reasonable levels of performance the case is well stated. Projekt (Czech Republic) makes an excellent example of this at a very reasonable price. It has no major weaknesses or flaws. It is only when looking for ultimate performance that the limitations emerge. The flywheel is not one of them, so it must be the spindle bearing, or the belt. As the spindle bearing is common to all, it is less in doubt, but current design may not be the best. Designers have reduced friction to the barest minimum, also drag in the bearing has been reduced - the latter may be a mistake. Conventional friction is two surfaces rubbing together, which at best, is an energizing source for vibration and resonance and cannot under any circumstances be a good thing. Drag is subtly different; it is the smooth resistance to motion requiring extra power to overcome. Logic would seem to include drag as a friction; however, it can be of benefit if the drag of the lubricant is significant compared to the drag the stylus and record experience. The belt is the real problem; in a typical design, it is very effective at decoupling vibration, so much so, that if the motor is forced to vibrate (a capacitor change on a synchronous' motor would do this.) Surprisingly little is degraded soundwise. If however, the power of the motor is changed, dynamics also change. It doesn't seem to matter if the motor is AC, DC or of stepper motor type, it's just the power available that matters. Alas, the belt stops what should be significant differences of motor being clearly heard. It is even worse from the point of view of the stylus in a typical system. A low drag bearing allows the stylus to display variable drag as the belt compliance allows this (some call this dynamic wow), the effect is a reduction in dynamics coupled with a shifting of stereo image. The more enlightened have seen this and are using stiff tape to replace the belt, it seems they understand the problem.

The idler system is very stiff, the mild damping it offers is less than is apparent at first sight. The reason is the idler has to be stiff to resist wear. The motor is almost directly coupled to the fly-wheel. This does raise a question. Is direct drive better still? In theory, it must be! The problem is with the direct-drive, the motor revolves too slowly to overcome the pulsing effect as the motor jumps from magnet to magnet, sometimes called cogging effect. A new principle of motor could overcome this. However, we don't feel it's happened yet!

501 development

The first prototype was half 301 and half what we now have as 501. This was the easy bit, nothing different to making a belt drive all the difficult parts coming from the donor 301. It was obvious from the beginning we were getting somewhere. Unfortunately the rumble was worse than a standard 301. It turns out Garrard were not stupid. All the movement, looseness and compliance, seemingly an error of the original design, were in fact, cunning engineering. Losing energy into the grommets, etc. We had to design a new motor to overcome this. Similar in type, albeit larger and with an innovation of an air suspension bearing, we call Aeroflux™. This motor self centers in its magnetic field and has no chaotic bearing noise, just the predictable rotational speed frequency and that of the energizing frequency (50 Hz). We now had the basis of our new turntable and were able to tighten the tolerances.

Recent developments

We have had ten years to tweak the 501; the only major revision has been to dispense with the motor pulley and drives directly from the motor shaft. A redesign of the power supply made this possible; we were surprised to find motor was happy to be stretched to higher rotational speed (3600 rpm at 92 rpm platter speed). Other than this nothing has changed. However, at a customer's request, we created a version with a stainless steel chassis. We were reluctant to do this initially as we doubted Garrard would have done it. We agreed with the customer that if we felt it to be spurious we would accept the cost and be honest enough to tell him if we felt it didn't work. We had always wanted to try this and it is now in our product line as the 501 Inspiration. The difference in sound is yet greater dynamics coupled with greater openness. The Inspiration does not replace the standard version, but is subtly better. While fully supporting the source of sound argument which states “no source can be too good”, it is arguable at this level the accompanying equipment has to be good enough to warrant the extra expense. Needless to say it is possible to upgrade to the Inspirational level, at a modest cost.

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