Crazy project #1: variable-pitch pullrods for JI tuned PSG.

[Georg]

Thanks Allan, yes, "cabinet drop" is an interesting subject ... when pushing pedals on steels with strings strung up on the cabinet, and pitch depending on everything staying perfectly straight, stable and in exact position under varying stress.

Let us forget for a moment that the strings are not strung up on the cabinet on my old, modified, steel, and that it doesn't matter much if the cabinet twists and bends like a seasick cow when pushing pedals and levers. Instead let us look at what effects additional mechanics with adjustments and control rods needed for JI tunable pedals may have with regards to unwanted detuning on regular PSGs.

1: The cabinet with changer, tuners etc, will be unaltered.

2: The number of pedals and levers will be unaltered.

3: How much force that needs to be applied to some pedals/levers for a given change may increase slightly, but nothing in there says it has to. No problem decreasing the force needed by introducing one or more of the usual "helper-spring" solutions.

So, the addition of mechanics for JI tunable pedals won't lead to any real increase/decrease in force/stress on the cabinet or any of its existing parts in any direction, so if a PSG has cabinet drop before, it will have the same cabinet drop after anything gets added.

If a player has to tune out excessive cabinet drop on a PSG without JI tunable pedals, chances are that PSG is totally unsuited for JI tunable pedals because one will only spread existing cabinet drop out on even more tuning-points. "Cabinet drop" and "JI tuning" are two totally different animals, and "cabinet drop" should be reduced to below audible levels for all changes before even contemplating adding "JI tunable pedals" into the mix.


We may have to start new threads on how to construct light, good-sounding PSGs with no audible cabinet drop. Maybe mac639 will start one, as it sounds like he may know how.

I don't have time to go into how I'll do it right now, as our farm-animals tell me it's about time I leave these PCs and start doing something useful. I'll be back... (but I can't say when)

[Allan]

I agree completely Mac. If the front and back vertical members are properly attached to the top they are NOT going to bend. I believe that the thousands of chapters of discussion that have been written on the subject could have been reduced to a few paragraphs if the expression 'CABINET drop' had not been used in the first place. There is no question that the phenomenon does exist but I simply don't accept that it is the cabinet that causes it. That need to be qualified in that cabinet drop in the real sense COULD happen if the body were to be poorly made or poorly designed to start with. Perhaps we should start a movement to change the expression to 'mechanical drop' or something else.
The very core of this thread, as you have obviously understood, demands that there is no 'cabinet drop' involved. Georg is looking to enable some tiny changes to be made on the fly in a repeatable manner. We have already agreed that the flex problem can be designed out and, therefor, ignored. Bent is in the club also, so we welcome you, as member #4, to the exclusive 'There Ain't No Such Thing As Cabinet Drop If You Build It RIGHT' club.
Keep us up to date on your build Mac, with pics if you can too.

Regards, Allan.....