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DIY Stompboxes => Building your own stompbox => Topic started by: casey on March 17, 2005, 02:18:49 PM

Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:18:49 PM
here's a strange question:

i think i remember hearing or reading somewhere that you can run an audio signal through a vacuum tube, and create distortion..what i mean is that the tube would not even have power to it.....almost acting like a diode or something of that effect...?

so the tube would just act like a non-powered "dead" component...

can this be done?
Title: uses for tubes other than amplifying....
Post by: ESPguitar on March 17, 2005, 02:20:48 PM
If so it would have been cool.. But i don't think it will work very well..

RB
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:31:36 PM
Quote from: ESPguitarIf so it would have been cool.. But i don't think it will work very well..

RB

i dunno....it would be interesting to experiment with these types of things....i would inject the signal in an unorhodox way....  if that makes sense... :roll:  maybe with a strong signal from a 386 chip.
Title: uses for tubes other than amplifying....
Post by: Connoisseur of Distortion on March 17, 2005, 02:33:13 PM
i STILL think that if we tried some of those tubes that came with a triode and a set of diodes as a clipper, we could have a sweet Electra distortion  :D
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:34:45 PM
Quote from: Connoisseur of Distortioni STILL think that if we tried some of those tubes that came with a triode and a set of diodes as a clipper, we could have a sweet Electra distortion  :D

would it be possible though to use an unpowered tube as the clipper?
Title: uses for tubes other than amplifying....
Post by: Dirk_Hendrik on March 17, 2005, 02:35:07 PM
The Fender performer 1000 works on this principle where the 2 halves of a 12ax7 are connected as diodes. However, there is a small DC current to get the tubes into conduction. Signal voltage  only is not going to work.
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:36:14 PM
Quote from: Dirk_HendrikThe Fender performer 1000 works on this principle where the 2 halves of a 12ax7 are connected as diodes. However, there is a small DC current to get the tubes into conduction. Signal voltage  only is not going to work.

uh huh, here we go....  now this is where im going....what about some type of diy stompbox with this principle in mind?
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:39:39 PM
also - i dont really care about the tube necessarily other than a different type of clipping...something uncanny maybe.
Title: uses for tubes other than amplifying....
Post by: aaronkessman on March 17, 2005, 02:42:04 PM
wouldnt you still need a filament power supply?

also, an example of a non-signal-amplifying tube may be in fender trem circuits.
Title: uses for tubes other than amplifying....
Post by: Gladmarr on March 17, 2005, 02:46:12 PM
If you look at www.metasonix.com or search for tube synthesizers and Eric Barbour, you'll find some pretty interesting audio uses for tubes.  Though I think this isn't really what you were getting at....
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 02:46:23 PM
Quote from: aaronkessmanwouldnt you still need a filament power supply?

yup, that's the question....    do you?
Title: uses for tubes other than amplifying....
Post by: dosmun on March 17, 2005, 03:04:55 PM
http://www.eldocountry.com/projects/tubeclock.html
Title: uses for tubes other than amplifying....
Post by: Paul Marossy on March 17, 2005, 03:41:29 PM
By design, tubes will not do anything unless the "correct" voltage is being applied to the filament(s). If no voltage is applied to the filament(s), no heat, no current - nothing happens...

EDIT- Try reading this page: http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm
Title: uses for tubes other than amplifying....
Post by: cd on March 17, 2005, 03:46:25 PM
You can use a tube as a clipper, like with a diode.  Take this into account though, a tube is going to cost you $5-12, not to mention the socket and power supply required to run it.  A diode costs 10 cents.  What would you rather work with?
Title: uses for tubes other than amplifying....
Post by: ESPguitar on March 17, 2005, 03:51:02 PM
Quote from: dosmunhttp://www.eldocountry.com/projects/tubeclock.html

:shock:  :shock:
Title: uses for tubes other than amplifying....
Post by: casey on March 17, 2005, 04:07:48 PM
Quote from: cdYou can use a tube as a clipper, like with a diode.  Take this into account though, a tube is going to cost you $5-12, not to mention the socket and power supply required to run it.  A diode costs 10 cents.  What would you rather work with?

i know, im just wanting to experiment for the fun of it.....and to see if i can get a different type of clipping than what a diode can achieve.
Title: uses for tubes other than amplifying....
Post by: SaBer on March 18, 2005, 03:36:17 AM
What is the second half of the first tube exactly doing in this schematic?

(http://www.triodeel.com/comp1.jpg)

I can't see anything else, than the signal coming from the first half, connected to the plate and grid...
Title: uses for tubes other than amplifying....
Post by: zachary vex on March 18, 2005, 04:07:41 AM
Quote from: SaBerWhat is the second half of the first tube exactly doing in this schematic?

(http://www.triodeel.com/comp1.jpg)

I can't see anything else, than the signal coming from the first half, connected to the plate and grid...

it's forming a rectifier (plate and grid are shorted).  rectifiers in compressor/limiters are usually used to accumulate a DC voltage (from the input signal level) that's used to control the output level.