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The Refurbishment of 1960's Walker Concussion Units


pcnd5584

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Does anyone have any practical experience of rebuilding and refurbishing concussion units of the type supplied by J W Walker in the 1960s? Whilst I suspect that those at Blackburn Cathedral (since replaced) and Paisley Abbey (also replaced) differed slightly in detail, there must surely have been some basic similarities.

 

It is interesting to note that the J W Walker instrument in Liverpool Metropolitan Cathedral appears still to have its original winding system - which I presume employs concussion units, as opposed to reservoirs - or is this incorrect? On the evidence of a number of excellent commercial recordings, they seem to work perfectly, the instrument not exhibiting shortness of wind, for example.

 

I am growing more concerned and dissatisfied with those here at the Minster and at present a rebuild (or even a restoration) is simply not an option. Is there anyone amongst those contributors or board readers who has ever dismantled one and therefore knows what I am likely to find? Our organ builder did once propose to install a temporary single-rise reservoir to the Positive Organ and remove, reverse-engineer and refurbish the concussion unit for this department. However, at present, we simply cannot commit to any financial outlay, even on this scale.

 

Please note that I shall not be attempting to do this on my own - but to assist our organ builder, should he agree to undertake exploratory work. However, as far as I know, he has never seen inside a Walker concussion unit before, and so neither of us really know what to expect.

 

We need to avoid (at all costs) damaging the instrument or rendering it partially inoperable, or compromising the integrity of any of the concussion units.

 

Consequently, if anyone is willing and able to give us some preliminary advice, it would be appreciated greatly.

 

For reference, the problems are as follows:

 

The wind system is (and apparently has always been) inadequate for the instrument. Not only do big chords sag in pitch (and occasionally volume), but there is some robbing between ranks (which may of course be soundboard or pipe planting problems). However, one only has to draw the Swell 8ft. and 4ft. flutes, play a three-note chord, then play one note on the Pedal Bourdon, in order to hear the pitch drop. It has got to the stage where it is beginning to be more noticeable - and irritating. What we would like to achieve is a more steady wind supply, with concussion units which actually react instantly to varying demands on the wind system.

 

Does anyone know if it is even worth attempting to do this - or is there anything else we could do, temporarily to alleviate this distressing fault, until such time as we have the financial resources to effect a complete overhaul and restoration?

 

Thank you.

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Interesting comments. I used to work with one of the old JWW (pre 75) men. I remember him telling me that there was a period when the independent comps did give trouble and that, if he encountered one from that period he'd advise chucking it out and replacing with a new unit. Problem is, I'm struggling to remember why. 1967 is a date in my head but I couldn't be confident. Apologies if I have the wrong end of the stick, concussions tend to be be on the ends of soundboards and sometimes units to steady the wind demand. I would have thought that your Walker had independent compensators and few if any single or double rise bellows. Probably just one breakdown after the blower. Before going there, I'd want to check that the cfm rating of the blower was adequate (I'd expect it to be fine, or maybe as you say an element of this problem has always been there, perhaps it isn't), that the air supply to it was not impeded and that any roller blinds were correctly adjusted. I'd also want to check the wind pressure from the blower and then check it at various points in the system ending up with the soundboards to make sure there is no resting drop in excess of what should be expected and then seeing if there is a significant drop at various points when under load. Basically you have supply volume and pressure maintenance and a sytematic approach should reveal where the issue/s lie.

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I would contact Adrian Gunning and Keith Bance. The former is organist at St John the Evangelist, Duncan Terrace, Islington and together they have loving restored and maintained this iconic Walker instrument. If they can't help I really don't know who else might.

Best wishes, Nigel

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I would contact Adrian Gunning and Keith Bance. The former is organist at St John the Evangelist, Duncan Terrace, Islington and together they have loving restored and maintained this iconic Walker instrument. If they can't help I really don't know who else might.

Best wishes, Nigel

 

I was going to suggest the same people but Nigel has beaten me to it. Adrian may even have some pictures of his wind system.

 

There may still be on ebay some pictures of a Walker regulator for sale that shows an inside view with what appers to be two very large pallets presumably linked to the top board in some way. From memory these were photographed in what could be an organ builder's workshop in Brecon. I think Go Organs have a facility there but may be wrong. I will have to see if I can find the ebay advert and post a link.

 

Hope this works; 4 days left. (Pipe organ reservoir)

 

http://www.ebay.co.u...669#ht_21wt_999

 

PJW

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SIOC rebuilt the 1965 Walker at Winthrop Hall, University of Western Australia (http://www.ohta.org.au/organs/organs/Winthrop.html) in 2008 and I think all of the winding system was kept with the 'schwimmers', one on each soundboard and I think a couple of single-rise reservoirs for the Pedal division.

The schwimmers were recovered and had the internal springs replaced and as far as I am aware there have been no problems with it.

 

I can possibly provide some pictures (inside and out) of these units if you wish.

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I would contact Adrian Gunning and Keith Bance. The former is organist at St John the Evangelist, Duncan Terrace, Islington and together they have loving restored and maintained this iconic Walker instrument. If they can't help I really don't know who else might.

Best wishes, Nigel

 

Thank you, Nigel - I had forgotten about this wonderful instrument. I shall see if I can contact Adrian next week.

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You may well have tried this.....but Richard Lea at Liverpool Meropolitan knows the instrument there well and might be able to assist.

 

A

 

Thank you, Alastair. If I am unable to contact Adrian Gunning, I shall come back to you regarding this.

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I was going to suggest the same people but Nigel has beaten me to it. Adrian may even have some pictures of his wind system.

 

There may still be on ebay some pictures of a Walker regulator for sale that shows an inside view with what appers to be two very large pallets presumably linked to the top board in some way. From memory these were photographed in what could be an organ builder's workshop in Brecon. I think Go Organs have a facility there but may be wrong. I will have to see if I can find the ebay advert and post a link.

 

Hope this works; 4 days left. (Pipe organ reservoir)

 

http://www.ebay.co.u...669#ht_21wt_999

 

PJW

 

Philip - thank you. However, I believe that the picture shows a breakdown single-rise unit. I think that our problem probably lies with the concussion units - or 'Schwimmers', if you prefer. (Although I had understood that this was a trade- (or brand-) name of a particular type of unit and that other similar items could not be referred to by this name, but simply called concussion units - or is this incorrect?)

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SIOC rebuilt the 1965 Walker at Winthrop Hall, University of Western Australia (http://www.ohta.org....s/Winthrop.html) in 2008 and I think all of the winding system was kept with the 'schwimmers', one on each soundboard and I think a couple of single-rise reservoirs for the Pedal division.

The schwimmers were recovered and had the internal springs replaced and as far as I am aware there have been no problems with it.

 

I can possibly provide some pictures (inside and out) of these units if you wish.

 

Reply by PM.

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Interesting comments. I used to work with one of the old JWW (pre 75) men. I remember him telling me that there was a period when the independent comps did give trouble and that, if he encountered one from that period he'd advise chucking it out and replacing with a new unit. Problem is, I'm struggling to remember why. 1967 is a date in my head but I couldn't be confident. Apologies if I have the wrong end of the stick, concussions tend to be be on the ends of soundboards and sometimes units to steady the wind demand. I would have thought that your Walker had independent compensators and few if any single or double rise bellows. Probably just one breakdown after the blower. Before going there, I'd want to check that the cfm rating of the blower was adequate (I'd expect it to be fine, or maybe as you say an element of this problem has always been there, perhaps it isn't), that the air supply to it was not impeded and that any roller blinds were correctly adjusted. I'd also want to check the wind pressure from the blower and then check it at various points in the system ending up with the soundboards to make sure there is no resting drop in excess of what should be expected and then seeing if there is a significant drop at various points when under load. Basically you have supply volume and pressure maintenance and a sytematic approach should reveal where the issue/s lie.

 

Thank you.

 

I was concerned to read the third sentence - I had heard this from other sources - although I wonder if the date might be 1965. Ours do not work at all well; however, those at Liverpool Metropolitan Cathedral (1967) appear to be fine. I hope that it might be possible to make some improvement by replacing the springs. Presumably the floating pans (if rigid - which ours are) are unlikely to need replacement, for example?

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This line is interesting - here is another of the 50s/60s Walker instruments that tends to get overlooked - speaking to friends who where at Ampleforth soon after it was put in it seems that the organ could do some exciting (and even fearsome) things - I have only heard it in recordings though. Interesting also regarding winding - Mark Venning mentioned recently that from the inside the RFH organ was just like a typical Engish cathedal organ from the point of view or mechanism, double rise reservoirs etc.

 

A

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We routinely remake the 1960s Walker units, which by the way are known in the trade as 'compensators'. They are a free standing version of a schwimmer.

 

The early Walker units do have their problems and there have been a number of important design improvements over the years in the valve, linkage, diaphragm, springs and damping. The latest units are very reliable and give a good steady wind supply. There is no need to go to the expense of replacing them by bellows.

 

Andrew Moyes

Nicholson & Co

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We routinely remake the 1960s Walker units, which by the way are known in the trade as 'compensators'. They are a free standing version of a schwimmer.

 

The early Walker units do have their problems and there have been a number of important design improvements over the years in the valve, linkage, diaphragm, springs and damping. The latest units are very reliable and give a good steady wind supply. There is no need to go to the expense of replacing them by bellows.

 

Andrew Moyes

Nicholson & Co

 

Andrew - thank you for this.

 

Could I ask one further question which has worried me: is this method absolutely dependable, or can any type of Schwimmer/compensator, etc, be unpredictable? (For example, with a traditional system of single- or double-rise reservoirs, the result is usually steady wind. However, I have noticed other instruments which use various types of compensator, and the results appear to be variable - some supply steady wind, others suffer from pressure drop and unsteady supply.)

 

Thank you.

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It depends entirely on who designs and makes them – you can’t generalise. Walker were certainly not alone in having problems in the pioneering days, just as the early neo-classical tracker organs here were not good. I would say those by mainstream firms who use them nowadays though will be totally dependable.

 

Reservoirs with wind controls, schwimmers and compensators are all ‘closed loop’ control systems. They all therefore have a natural propensity to be unstable and resonate at a certain frequency. At one extreme, there are double rise reservoirs that use weights rather than springs, because the pressurising force must be constant. The large masses involved mean they have a low natural resonant frequency, often around 5-6 Hz which is well within the range of speed at which it is possible to play repeated notes. Such reservoirs can easily be ‘excited’ by playing at just the ‘right’ speed.

 

The resonant frequency of small single rise sprung reservoirs is higher because the masses are lower. That of schwimmers and compensators is higher still, typically around 30 Hz, because the parts are small and light. When they go unstable, they vibrate. This is faster than you can play repeated notes which can be used to advantage. It means that an oil-filled damper can be fitted to calm the device at its resonant frequency but will have little effect at lower frequencies where you want the device to respond freely to your playing demands.

 

Firms often hold strong opinions on modern winding, perhaps depending on whether their past experience has been good or bad. For what it’s worth, mine is that schwimmers are more predictable than reservoirs in the way they perform and are easier to stabilise when needed. Ours produced in the last decade or two have been 100% reliable. I am sure the same can be said for Messrs Klais, Rieger, Tickell etc who regularly use modern winding.

 

Whether there is a droop in pressure mainly depends on the design of the springs used; simple coil springs are unsuitable. By using pantograph springs, we can deliberately set them to give a slight rise in pressure as demand increases to compensate for the pressure drop in soundboard bars. There is a musical argument for this too. Wind instruments are blown harder when louder.

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I would entirely endorse Andrew Moyes's remarks. However I do feel we may be collectively jumping the gun a bit in assuming the comps are at fault. Having been faced with some complex winding problems in the past, the only way of identifying the cause, be it single or multiple in nature, is to test each component. Start with the blower and work your way along, testing either side of each component with static pressure and then under load. I'd hate for you to think the comps need replacing when the problem could be more simple, or indeed lie in other areas. Apart from the fact, you'd have to answer the question about which comps need replacing as you can't assume the fault lies with the division you hear it worst in. There's no substitute for a methodical approach, assuming nothing at the outset.

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I would entirely endorse Andrew Moyes's remarks. However I do feel we may be collectively jumping the gun a bit in assuming the comps are at fault. Having been faced with some complex winding problems in the past, the only way of identifying the cause, be it single or multiple in nature, is to test each component. Start with the blower and work your way along, testing either side of each component with static pressure and then under load. I'd hate for you to think the comps need replacing when the problem could be more simple, or indeed lie in other areas. Apart from the fact, you'd have to answer the question about which comps need replacing as you can't assume the fault lies with the division you hear it worst in. There's no substitute for a methodical approach, assuming nothing at the outset.

 

This is helpful, Porthead - thank you, too.

 

However, there is not really any department where the problem is more noticeable than in others. In some ways, the Pedal Organ is more stable than most. For some time now (a good number of years), the organ sags somewhat on fuller registrations. In addition, even quiet registrations are not exempt. Occasionally, it seems to sound far worse than other times. The, I just turn off the blower for a while, only re-starting it immediately prior to when I have to play the next hymn or choral item.

 

Naturally, this causes havoc with the tuning. Fortunately our organ builders have good ears - and endless patience. Once two ranks have been tuned together (particularly the reeds), the addition of a third upsets things, and so it is then necessary to try to achieve a compromise, carefully balancing the addition of each new rank with what has already been tuned.

 

I take your point about a methodical approach. However, since there is ample documentation that Walker compensators from this period were (and are) of, shall we say, uneven performance, I am fairly certain that this is where the problem lies. However, I am no expert on the winding side. If you still think that it is worth checking every other component, please do not hesitate to tell me.

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