A difficult LP reproduction question

Albertporter...I guess I didn't grasp that your objective is to find a turntable with wow and flutter, rumble, and speed variation, to augment the 78 rpm surface noise, and recapture that nostalgic sound of your youth! In that context an idler wheel table fits the bill perfectly.

Records were made at various speeds, but those which are not 78rpm aren't properly called "78s". The 78rpm standard was established to end the speed inconsistencies, just as the RIAA equalization standard was established to end the need for multiple equalization curves in preamps. The speed range that you cite agrees with what I remember, and does exceed the range of adjustment for most turntables that provide for speed adjustment. Can you explain why an idler wheel drive permits more adjustment than some other form of drive? Or is it just that when turntables were made with a wide range of speed adjustment, idler wheel drive was the only show in town.

I can help you there, Eldartford. The Lenco can play over a wide variety of speeds because the spindle against which the idler wheel turns is gradually machined from "fat" to "skinny", the idler wheel itself is carried on a sliding support to transport the wheel to any point along the spindle in infinitely variable increments, much like analogue itself versus the chopped-up digital version of music. Quite ingenious, and the reason why the Lencos are the darlings of the 78 crowd.

As to wow, flutter, rumble and speed variations, these are problems which affect belt drives as well, which is why these figures are given out even today. As well, belt-drive motors (cogging 150-300 rpm motors) often exhibit problems, as they are not nearly as well-built as the smoothly-spinning cogless, 4-pole, 1800-rpm idler-wheel motors of yore; belts are rubber bands which constantly react to "stylus drag" every time the needle hits heavily modulated passages (which is why so many belt-drives - even high-end ones - lose it when things get complicated)...all problems which do not affect properly set up idler-wheel drives. Probably why Sugano used a Garrard 301 in designing his Koetsu cartridges. Here I will quote from a very knowledgeable and logical man of open and working mind, Rudolf A. Bruil: "In order to achieve a perfect and steady turning of the record an EMT, a Thorens TD124 and a Garrard 301 and 401 (and also the early Goldring/Lenco) each have a heavy platter, a strong motor and an idler wheel which make the platter turn in a steady fashion, without a trace of slowing down when loud and complex passages suddenly occur. The isolation of the motor should be maximal. The rubber of the idler wheel should be durable and should not transmit motor vibrations to the platter at the same time. The circumference of the idler wheel needs to be impeccable. If this is not the case then rumble, wow and flutter will be the result...In the nineteen seventies several firms started using a heavy platter (6 to 20 kg) with the bulk of its mass concentrated on the periphery in order to achieve extraordinary values for wow, flutter and speed accuracy. If the shaft (spindle) and the bearing are engeneered from the best materials and to close tolerances, the playback of an Lp can give stunning results if arm and cartridge are also of high quality." Lencos with the rubber-covered aluminum idler wheels never have flat spots or other irregularities, the motors and platters are hand-balanced in labs, the platter has much o fits mass concentrated on the periphery, the motors themselves have their own three-point true spring suspension, and the main bearings are excellent. It's all in the execution.

Here is a quote from one of the few comparisons ever made between a modern high-end 'table, a Michell Gyrodec, and a rebuilt idler-wheel drive, the Garrard 401, in Hi Fi World: "I also strongly suspect, after listening to the very clean transient starts and stops supported by this turntable, that its high torque drive system suffers less from dynamic slowing than belt drives. That's why it not only sounds dynamic, but has a very good sense of pace and rhythmic control. The rumble demon has been banished completely by Martin Bastin's new bearing and plinth. Previously it measured around -25dB at 25Hz, relative to the DIN rumble test tone. Now, the spectrum analyser shows 25Hz level measures -60dB, looking like ordinary disc surface noise rather than a discrete rumble component. The smoothness of the rumble spectrum indicates there is no rumble as such."

So, if by recapturing the sound of our youth you mean music played with the proper authority and spot-on timing, which is absolutely crucial to proper reproduction of music and hence musical thrills, then yes, I agree with you entirely.

Johnnantais...Thanks for the good writeup about idler wheel turntable technology. The ones that I had, including the ubiquitous Garrards, never worked that well, and were easily surpassed by early belt drive tables like the Empire 598 that I used. Perhaps the belt drive is just harder to screw up, and doesn't require the precision engineering and construction needed to make the idler wheel effective.

The speed changes that you cite as a result of groove modulation is something that I have never actually seen (with LPs) using a strobe on either my belt drive or direct drive tables. Probably it happens more with 78s, and perhaps the phono pickup and downforce play a role. I have long used Shure V15 at about 1 gram.

Johnnatais has answered the variable speed questions about the Lenco.

As for why this is necessary, here is a section from a page on 78 RPM disc playback.

      By no means all 78s were actually recorded at 78 RPM. Even in the late 1920s English Columbia was still using 80 RPM, and prior to about 1921 speeds were widely variable. Some of the audio tracks included in the Music hall section of this site were transferred at speeds as low as 74 RPM, and I have come across records where the speed was as low as 68 or as high as 84 RPM.

As to a turntable capable of coping with these speeds, that is yet another problem. Few turntables have more than a tiny variation (usually 2 or 3 per cent, which is nowhere near enough); but electronically controlled turntables may be modifiable. You need a speed range of 72 to 82 to cover most records. I'm using a Goldring-Lenco turntable which has a mechanical system for continuously varying the speed from about 32 to about 84 RPM, but it's not available any more - indeed I have had mine since 1963

Exactly why I think it's a valid choice for 78 RPM playback and still deliver good performance on modern LP.

Eldartford, the speed variations caused by belt reaction falls beneath the radar, so to speak, happening too fast to be captured by a strobe. This is why certain 'tables measure superbly averaged over a minute, yet don't hold up sonically (audibly) under pressure. But it is audible as confusion, loss of focus, orchestra melding into a single monstrous violin, loss of attack, and so on. And yes, it is far more difficult to design and properly set up an idler wheel drive than a belt drive, which is why belt drives won the war: a matter of price and profit margins. Fortunately there are the Lencos, whose simplicity in execution and design (a closed system of silent high-torque motor, perfect idler wheel and high-mass flywheel/balanced platter in which groove modulations have no effect) makes optimization much easier. The models I recommend were built from the late '60s to the mid-'70s, when many of the problems you cited were identified, understood and eliminated. I had never actually thought about the effect of stylus pressure, and you're right, lower tracking force would go some way towards mitigating this effect in belt drives, but with the Shure stylus profile (which digs deeply) the problem is increased, probably balancing out in the end. Yet one more thing I will have to experiment with!