[TenTec] Low Pass Filter

[Rick Denney]

Dr. Gerald N. Johnson writes...

> So you reach over with your free hand a slide the slide tuner in and
> out to fix the remaining errors. Many I've seen (but not mine) slide
> as easily as a trombone slide.

I do that on my four-valve Bb tubas, but not on my five-valve F tubas.
They don't have slide positions that are easily adjusted, and I can
usually get close enough for the notes I'm asked to play with five
valves to adjust my buzz (er...exciter frequency).

> My old Eb big bore Holton tuba has
> worn valves that are not in perfect alignment and its tone is not
> well centered. I have to lip (and can lip nearly a half step each
> way) each note to correct for the leaky and misaligned valves. Need
> to get it a valve job or find another horn. If I had the space maybe
> a Conn 24J or 25J.

I have a Holton BB-345 Bb tuba, which is a real monster. Last year, I
had the valves redone and the slides aligned and fitted to perfection.
I have to be careful that the slides don't fall out when I set the
tuba down on its bell.

I had a 20J for a while, but I found that the third-partial F was so
flat played open that I had to play it 1-3 (which is normally grossly
sharp). Those Conn big-a$$ tubas (yes, that is an official
description) have notoriously flat third partials. The Holtons can be
that way also, but mine isn't (it is sharp on the 6th partial,
though).

Parallels for content:

1. Adjusting tuning slides is like using a SteppIR antenna.

2. Pressing valves is like switching in lengths of transmission line
(such as with an old Johnson matchbox).

3. Leaky valves are like adding a resistor to a tuned circuit to lower
the Q (which is why you could bend the pitch so easily).

>>
>> Okay, that's about as much trouble as I can get myself into for one
>> day.

It's a new day, but I think I've already pushed it too far.

Rick, KR9D