I yesterday my "roll bar" equipped Shaka Tube took a tumble to the concrete floor.
At first I thought the roll bar had done it's job. I was happy the tube didn't shatter.
But this morning I noticed a white-ish discoloration in the tube.
Upon close inspection I can see the tiniest of cracks right at the point.
The vacuum has been compromised! The roll bar failed to protect the tube.
My attempt to protect the tube by dropping the socket down with stand-offs didn't work.
Rick - UK ( Frequency Central) you are so right to hide those shy little babies away! :icon_redface:
Tubes are shy creatures that prefer to live an enclosed life.
(http://www3.telus.net/public/david65/pedal-pics/rollbar-failure.jpg)
However the powder-coat finish wasn't even scratched!
Dave S.
(just because you saw someone else do it doesn't mean it's a good idea)
Damn! That's sad. My commiserations to you. Still, it's easily replaced.
I must admit that my first Valvecaster had the tube sticking out and no rollbar. With the six tube pedals I've built since I've employed my 'shy tube' strategy.
Though I have recently been thinking of doing a turbo charged 6111 Subcaster in a 1590A enclosure with tiny rollbars. Hmmmm............
Maybe you should start wearing a helmet while out on your Harley Pan Head with Suicide shifter - and hiding your tubes.
You tube pedals do look ace though.
kinda off-topic, but is it ok to use tubes inside a box? shouldnt we have to do some openings for air flow, because of heat?
Quote from: drk on October 29, 2008, 10:30:35 AM
kinda off-topic, but is it ok to use tubes inside a box? shouldnt we have to do some openings for air flow, because of heat?
(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0369.jpg)
Quote from: frequencycentral on October 29, 2008, 09:47:47 AM
Maybe you should start wearing a helmet while out on your Harley Pan Head with Suicide shifter - and hiding your tubes.
NEVER!
(http://www.biker-patches.com/images/bp/patches/Helmet_laws.jpg)
That mini tube 1590A would be sweet.
I've always wondered when this thread would pop up. I think you've all been aware of the risks. The rollbar was just a provision you took to try and detract from the hazards of leaving a tube outside.
Why do we do it?
Because it looks ace!
I've actually always been worried more about errant stomps than dropping the pedal. My consolations for the tube's departure.
I'll keep this in mind when I make my Valvecaster, Valve Tremelo, and my Pepper Shredder (waiting for $$ for all these builds)
I've never been keen on external tube mounting for a pedal. As kewl as it might look, eventually it will fall and break or get stepped on. It's just a matter of time. One 12ax7 will easily fit in a 1590bb- you might even be able to wedge two in there.
Quote from: DougH on October 29, 2008, 12:26:54 PM
I've never been keen on external tube mounting for a pedal. As kewl as it might look, eventually it will fall and break or get stepped on. It's just a matter of time. One 12ax7 will easily fit in a 1590bb- you might even be able to wedge two in there.
(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0260.jpg)
Good time to mention Paul Marossy's original Shaka Tube web page.
http://www.diyguitarist.com/DIYStompboxes/ST1590BB.htm
The most well documented way to mount a tube inside a pedal. Pure genius.
He even gives you the plans to fabricate the bracket.
This method would work for many a tube pedal.
(http://www.diyguitarist.com/Images/ST1590BB-Interior1.JPG)
...is that an IKEA drawer handle I spot as rollbar?... ;D
j
Now you know why we did not use roll bars on the
TubeUlent. There were all kinds of issues with the bars. To make bars effective you have to adhere to some careful guide lines to maximize the protection give by the bars. Some people have attempted to criticize our use of plastic for tube protection but we did test the plates on the
TubeUlent for impact, drop, sheer, static, and other loads.
Quote from: frequencycentral on October 29, 2008, 09:47:47 AM
Maybe you should start wearing a helmet while out on your Harley Pan Head with Suicide shifter - and hiding your tubes.
You mean a suicide clutch and hand/jockey shifter ? Sorry, pet peeve.
Andrew
wow TG that thing looks awesome!!!!!!!!
And if you put the tube in the box, it's always nice to make them visible.
Here are some examples how it can be done.
And to show them of, just put a led underneath them! ;)
(http://i301.photobucket.com/albums/nn69/Joppes60/6111Infinityledson.jpg)
(http://img514.imageshack.us/img514/605/zijfc8.jpg)
An idea I just thought of to actually maybe make this safer and possible is to mount the tube half-way sticking out, on its side.
(http://img359.imageshack.us/img359/9209/tubefq5.png)
And then put two roll bars positioned next to it.
And I know that's a very bad drawing, don't worry, :D.
Quote from: drk on October 29, 2008, 10:30:35 AM
kinda off-topic, but is it ok to use tubes inside a box? shouldnt we have to do some openings for air flow, because of heat?
I'm not convinced that the heat from a tube heater is a big issue. Now, if you have silicon (transistors, etc) inside the box too, maybe it is. But if the circuit is just R's and C's, I'm not sure ventilation and etc is really necessary. My pentode driver never gets hot on the inside- never. And it has 2 tubes. Now I did put a couple ventilation holes in the sides, but I'm not convinced they are that effective. The tubes themselves only get slightly lukewarm to the touch. None of the surrounding components ever feel warm when I check it. And this has an op amp and some other Si in it too. The caveat is that this just applies to voltage amplification. With power amplification it's a different story.
Quote from: DougH on October 30, 2008, 08:24:36 AM
I'm not convinced that the heat from a tube heater is a big issue.
I hve to agree re 12AU7. 6111 are another matter - they get very hot.
I don't know why there would be a difference. They both pull 300ma of heater current at 6.3v.
Quote from: DougH on October 30, 2008, 01:18:39 PM
I don't know why there would be a difference. They both pull 300ma of heater current at 6.3v.
You wouldn't think they would, but the sub mini's get to hot to touch.
Quote from: Jered on October 30, 2008, 07:25:50 PM
Quote from: DougH on October 30, 2008, 01:18:39 PM
I don't know why there would be a difference. They both pull 300ma of heater current at 6.3v.
You wouldn't think they would, but the sub mini's get to hot to touch.
......though my 5672's don't even get a little hot - or glow. :-[
It's the voltage regulator or voltage drop resistor that gets hot with them.
Well, I'm sure there's more to the "heat" issue than just how much current they pull- that was just the first thing I thought about. Size of the envelope, materials used, thickness of the envelope maybe? I'd guess there are a lot of factors that come into play.
You needs a roll bar on both sides of the tube methinks.
thanks :)
I'd guess there are a lot of factors that come into play.
Effeciency of the heater element, size of the tube.
I got a tube socket that accepted nicely a little 1/8 machine screw, [this socket has a hole through the middle. the thinly cut threads [using the screw] seemed more than sufficient going through more than a 1/2'' of socket body material.
Long machine screw through: Rubber washer, washer, perfboard, 1/4''wide x 1/4''tall insulated tube [ballpen casing], into the sockets threads.
That puts the tube socket on a 'shock absorber' mount, and uses the circuit board to place the tube in the enclosure.
A slotted aluminum strip, salvaged from inside a monitor, 2''w, long...[like 8 inches?], was easy to bend because of the slots that had been stamped in it, goes all the way over the tube, only 2 sides left open, enough open 'angle' to allow positioning the eyes to view the glass, providing 'better protection.
Start with a plate of metal like:
l
-----------------------------------
l
form the center length of the strip laid flat into a 'U' shape. The strip/template must be long enough to span over the tube and have tab ends for screw mounting into a boxtop, after bending the 'l' tabs to form side guards for the tubes new 'wrap-around U' tube guard.
In the case of a tube socket near a side, make a lopsided 'U' guard and use the side to fasten the longer tip of the U.
You can use self tapping screws to mount the guard to the substrate[s.
~Easy trick except the metal working, unless your'e into metalurgy.