Re: Ampico B Response Question
By Craig Brougher
Dear Mr. A.B. Bonds (Awkward. May we have a first name, please?) is still in a bit of a controversy as to whether or not Ampico A's and B's are good for 88 note roll music. I have made a number of professional quality recordings from my own Ampico B grand, just playing 88 note rolls. It is perfect for it. Sounds better than an upright, even on a recording. The advantage is superfast, sensitive response that doesn't miss anything, whether the roll is cut with too small holes or not. It also plays every note at exactly the same intensity-- something that no upright player can do (for reasons I don't want to get into here).
The Ampico A can do the same thing as well, without having to keep the two buttons depressed all the while. But as I said in a previous letter, both instruments will need a little gizmo eventually that does the trick automatically when you switch the "A"s Automatic switch to OFF.
Simply disconnecting the no. 6 tubes will not work very well unless the no. 7 tubes are also open. On the A, this is automatic only when you put the piano into its Ampico OFF mode, but on the B, this is not automatic and holes or tears in some rolls can trigger the full power of the piano, and you'll end up running out of the room with your hands over your ears.
If anybody wants me to build them a gizmo for either piano, I will be glad to do it. It is trouble free and easy to install. It just sort of "hangs" there in the tubing if you want it to, or you can mount it, since it has mounting holes. Contact me personally for details.
As far as comparison performances between A's and B's, I refer to my letter in the AMD # 96.07.04 regarding "Playrite" rolls. Take the challenge. Here is the principle involved, and I wouldn't say it if I was unsure of myself on this, because it is cut and dried and will never fail to work: Buy a good Ampico B test roll from Keystone Rolls, set up your Ampico B at the _designated pressures_ which are stamped on the roll or recommended, and don't fudge. Set your soft pedal to the correct lift height, and then go through all the tests a number of times to make sure you don't have a few functions that are intermittent, then I promise you that your B will perform exactly as it is supposed to.
(By the way, do not use the "Marshalltown" vacuum gauge for these measurements. It isn't even repeatable from trial to trial on a steady vacuum source. And if you use a water column, be sure you have a water trap bottle in line, or you will end up soaking the valves and pouches.)
The problem is almost always stack valves, plus expression curtains that somebody decided "looked ok." If you want to know whether or not your valves have been restored, pull a couple and just look at the outside finish on the block. They cannot be broken open, repouched, and reglued without any evidence of that. I begin by sanding them all down first so the joints in the blocks can be located and split open without splitting off, anyway. I don't see how it could be done differently in that respect, but perhaps somebody has come up with a different way. I suspect that if your valve blocks still have old, hard, shiny brown shellac on them, they have not been repouched.
Anyway, old pouches and old ball bleed valves are the death knell to every model B Ampico's "like new" performance." It cannot be done. The pouch leather used has to be very, very flexible and light, and very very tight, because it must actuate on a separate # 70 fixed bleed, first. That means that if your pouch leakage is more than perhaps 10% of the fixed bleed leak, you do not get the advantage of the ball bleed anymore. And if you try to seal the present pouch leather offered today with rubber cement to that degree, you end up with very stiff pouches that are going to continue to stiffen and take a set in the form of a dish, then they will eventually have the typical doughnut shape and will sit at half-mast, supporting their own lifters, just like most Ampico B original pouches do, today.
Another element is the ball bleed valve. We have sawn apart these ball bleeds and in every one of them, the seats are hopelessly pitted and leak to one degree or another. They should be cartridge--tight. New ones can be purchased from Robert Streicher at very reasonable cost, and they are excellent, now. But the old ones vary. Some are tight. Some are evenly leaky, and some are varying, depending on how the ball reseats itself each time. But I have spoken to Robert in regard to his sales, and he tells me that very few people have his ball bleeds in their pianos.
Another problem with the valve blocks is that most of the blocks leak right through the shellac to air. You can tell this very simply. wet the side of a block with your tongue, and then draw a vacuum with your mouth sealed against the end-grain sides of the block and your tongue lightly against it. You will feel the buzzing feeling of dozens of little air bubbles forming and breaking as you suck down. Add these all up, and you have a major source of vacuum loss.
Yet another problem with the valve is that when they are reglued, the little ball bleed hole gets sealed off with hot glue, where it enters the pouch board. So as each valve block is reglued, a little tool has to be made to dive down into that hole and clear it out.
And another problem is that Ampico valves are commonly set by a gapping tool. That is not very wise, and doesn't allow the valves to be at all consistent. Gapping tools may be ok for upright player pianos, but not reproducers. A conscientious rebuilder will construct a tester that allows the B valve to be gapped while actually being "played" at 4.5" of vacuum. That is why most Ampico model "B"s will not pass all the repetition tests on the test roll. Their valves were set with a gapping tool.
You may want to read up on these testers and methods in my book, The Orchestrion Builder's Manual and Pneumatics Handbook, available through myself, or the Player Piano Co. in Wichita, KS. The day that we are able to regulate a grand action by aligning everything up in straight lines and then just closing the lid, is the day we will be able to use that same technique to regulate player valves for consistent actuation, too. (That doesn't mean that technicians don't try to do it that way!) Until then, though, You had better treat each note and each valve like he was an individual. You will be a lot closer to being correct, and the performance will improve.
Craig B.
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(Message sent Sat 6 Jul 1996, 14:38:56 GMT, from time zone GMT.) |
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