Tubes (was Re: modular building)

[Bill Layer]

Dan,

Monkey! Aaaiieee!

>Ok, you got me interested.  The reason I've not considered tubes is that
>they scare me.  :-)  But seriously, what are the issues in tube design?
>I don't even know how to power such a module, let alone how to build it
>(I presume you can't use veroboard?).  I've seen schematics, and they
>look simple enough.  How would you interface such a module with an
>existing set of solid-state modules?

First: Goto the Eric Barbour schematics at Engineering Musician Web Mag
-or- Kevin Lightner's 'Synthfool' (in my humble opinion, the home-iest
synth site on the net, like Summit beer on TV) and download his articles.
Eric is very good at giving exactly enough advice (not too much, nor too
little) on construction of his modules. However, they are not for
'first-timers' without a little background info, which I can certainly help
fill in.

I've personally built a couple of his modules, and can say with utter
certainty that they work as described. As to be expected, I'm designing a
set of my own modules as well, with a liberal borrowing of concepts and
basic circuits from Eric. Start with his simple circuits; the VCA first, as
it is the simplest, and gives the most advantage as it is the last link in
the audio chain, and will endow the entire completed signal with it's
character. Or if you're feeling bold, try the VCO first. The sound of this
unit alone should be sufficient stimulus to proceed...

Power is easy; +/- 150 DC for the cirucits (actually, this is pretty low
voltage for tubes), and 6.3VDC for the filaments. See Eric's simplifed
power supply; better designs are quite possible.

Construction? Eric suggests 19" rack panels, which I feel is a so-so idea,
as it directly exposes the glass tubes to the user's hands, which could be
problematic in some (performance?) situations. Elsewise, it's a great
solution, as the simple circuits can be built up on terminal strips on the
rear of the panels. I've built tons of tube gear ( I worked for Atma-Sphere
for 3yrs) so I can be of much help here...

Interface to SS gear in most cases is as easy as attenuation! (must not
blow-up our good stuff, now) Once an all-tube synth is built and running,
one can really act like a fool, as the units are nigh onto impossible to
damage.

Now I'm really getting fired up. Lets go!

"Quantity has a special quality all it's own"
			--John Lennon




------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
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