I recently received the motor back for my Expert Senior, and it works well! However, I do have two questions, as the volume doesn't seem to be as loud as it can be, even though I have to my knowledge regreased and sealed all of the tone arm joints.
1. The motor is mounted to the holes provided in the motorboard, however the tone arm doesn't seem to line up with the turntable spindle, even when the proper angle is set for the sound box. As you can see, the tone arm arc doesn't cross through the turntable spindle, and there thus seems to be a tone arm tracking problem. Could that account for a decrease in volume?
2. Is the turntable set too high? If you look at the image of the record spindle hole for the record, the top is nearly flush with the spindle.
In any case, your thoughts are greatly appreciated!
Last edited by Garret on Mon Dec 23, 2013 1:19 pm, edited 1 time in total.
Firstly, well done for now having a working instrument---how happy and satisfied you must be. The volume problem seems rather strange as tracking, good or bad (within limits !), should not really affect the level of sound. You have presumably checked that all trunking is completely clear---no table tennis balls in evidence ?!
Secondly, the volume question could have to do with the soundbox and I notice you have an EMG two-spring lying on the deck. What is the situation when this is used---how do the two compare ? The Expert two-spring on the tonearm seems to have a crease or two in the diaphragm but this is more likely to affect sound quality rather than volume. Have you used very compliant rubber either side of the diaphragm and is it set in a central neutral position ? Are the springs tightened just sufficient to maintain mechanical coherence/support whilst affording the possibility of maximum deflection ?
Thirdly, and in relation to tracking, what is the distance between the motor spindle centre and the tonearm bearing centre ? In my experience, it should be 11 ½ inches (EMG 11 inches---swan neck).
Fourthly, is the motor you are using the same as the original ? Does the winding shaft centre line up with the original escutcheon bore in both planes ? In other words, is the current motor spindle likely to be in the correct position ? From the photos it seems to be too close to the tonearm bearing. It may also be that the turntable (mounted above a plinth) is now higher than original which will slightly adversely affect the tracking but, if the 11 ½ inch requirement is satisfied, the problem should be resolvable by small changes of the soundbox angle on the tonearm.
Fifthly, the needle point should NOT pass through the centre of the motor spindle but should lead or overlap it by approximately 3/8ths to slightly over ½ inch. Use of a Wilson protractor will enable you to set the overlap accurately. The attachment shows what you have to make or borrow---cut out of cardboard. Note that needle projection also affects tracking. The subject of accurate tracking is quite involved and perfection is only possible with the Balmain system where the soundbox is connected directly to the end of the horn which itself is suspended on a bath of mercury (or wheels). It is then possible for the needle to traverse the record in a straight line at a continuous constant tangent to recording grooves. In that specific case, the needle point would end up at the spindle centre. On all other systems where the tonearm is swinging in an arc, compromises have to be made but variations from a perfect tangent of less than two degrees should be possible with an Expert tonearm (very carefully designed) and a correctly located motor spindle. This represents an acceptable error for all practical purposes and record wear will be kept to a minimum.
It is worth the necessary work of checking the tracking at the outset to give long term peace of mind that your records are being best treated. Study of the geometrical requirements set out in the Wilson/Webb book will pay dividends. When viewing the relationship between the parallel lines on the swinging protractor arm and the plane of the diaphragm, you may have to remove the case lid stay to enable direct overhead sight unless you are quite short-sighted !
Superbly informative reply Graham. We would all be floundering in the dark on such matters without your wealth of experience, study and engineering acumen. Precise tracking really does make a big difference and it's astonishing how little attention even the biggest firms paid to it.
Attached * is a printable document from which anyone can make a Wilson protractor.
* Edit - incorrect instructions - see new version posted 28th December.
Last edited by Orchorsol on Sat Dec 28, 2013 4:05 pm, edited 1 time in total.
Your Senior may well originally have had a Paillard GGR 255 motor. This would not have incorporated a plinth, thus the turntable would have occurred at a lower horizontal level, slightly assisting correct tracking (but not by the amount your photos show you need) as was said above. In plan view, the winding shaft centre line would have been about 1 5/8ths inches behind the spindle centre. What is the equivalent distance for the motor you are now using ? Unless the measurement is identical, this could well be where your main problem lies.
It is also worth noting that Expert did make a slightly longer tonearm---plus ½ inch I think---but these were destined for the largest All Range model as far as I know. I think I am correct in saying that yours is standard Senior ?
Going back to the inadequate volume question, I wonder if the soundbox diaphragm is airtight? Have you carried out a gentle smoke pressure test ?
I switched soundboxes last night, and the difference was astonishing. While the gold Expert soundbox sounds great on a smaller horn and passes the gentle pressure test (I acquired it from a friend of Ian's), I just felt it wasn't doing the Senior horn justice. The sound was just too quiet for the Senior, and some relatives here for Christmas agreed. When I switched soundboxes to the silver EMG two-spring, even my relatives at home could tell the difference, as it was substantial. Not only did volume increase substantially, but the sound quality also improved markedly. In fact, the sound quality was such that my relatives, no fans of ancient recordings, listened to music for nearly an hour. Yes, my Expert has a standard-sized horn. While at first the Senior sounded no better than the HMV 163, it now sounds much better. However, I can't help but believe that further tweaking may improve the sound even more.
At some point in it's life, the Expert was clearly remotored from a spring wind to the current electric Garrard Flyer. I am not sure how professional a job the replacement was, especially because the cuts in the motorboard to accomodate the motor seem somewhat amateur. I guess I will find out for sure by trying your alignment protractor. I have seen similar alignment protractors before, which were supplied to dealers by the Edison Company for setting up the rare Edison Long Play Diamond Disc phonograph mechanism, but nothing for gramophones. I will let you know the results. I will also measure the tone arm - spindle distance.
I would like to switch the motor back to a spring wind, because even though the Garrard has been expertly restored, it does have a noticable hum. Also, if I were to ever go off the power grid, I would love to be able to play records on this beast of a gramophone! I do not think that this gramophone had a Paillard motor, given that there is an outline shadow for a face plate on the motorboard.
More photos and details to come. Thank you so much for your help and advice.
Check that distance from spindle centre to tonearm bearing centre because the tracking definitely looks wrong from the photos---by anything up to an inch. The trace of the metal plinth on the wooden deck-board can happen quite quickly so it may be misleading to suppose that it has anything to do with the original spring motor. In my experience, people replace motors without really understanding how tracking works and its importance. It is quite a difficult proposition to find replacement motors which have all the correct co-ordinates---usually, new holes in the deck-board have to be bored and sometimes new replacement items made. If it were mine, I should make a dummy deck-board and mark out the correct intersecting arcs to establish the essential positions referenced to the new spring motor you are going to use. Sometimes you may be lucky to be able to utilise the original escutcheon bore but, more often, a new hole will have to be made. It may be possible to swing the position of the intersecting arcs in such a way as to marry up the winding handle shaft with the original escutcheon bore even if that means that the motor spindle is not central in the case. If the difference is slight, you may be able to employ a larger escutcheon to mask the adjustment etc. When you have the new template, you will know exactly which motor to look for. In the meantime, you could also use the dummy deck-board to reposition the electric motor with correct tracking. At the end of the process you should have taught yourself all about the finer points of tracking !
Let me know the necessary measurement from motor spindle centre to winding shaft centre (plan view) with the spindle in central case position (lateral) and I will try to establish what the original motor was.
Here's the measurement for the turntable spindle to the center of the tone arm bearing. It may be slightly closer to 11.5", but my tape measure is being unwieldy. Printing off and preparing the Wilson alignment protractor.
Since you say the motor was once spring wind, there is presumably an unused escutcheon and hole on the right hand side of the case ? What is the measurement from the centre of this hole (projected to a point behind the spindle with a set-square) to the centre of the motor spindle (measured at right-angles, of course)? In other words, how far behind the spindle centre does the axis of the winding shaft lie ? It could, of course, be coincident or even in front but we need to know to begin to establish what the original motor was.
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