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Shaka tube ?

Started by Grizz, April 10, 2008, 09:15:07 AM

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Grizz

The Parts list says I need a 12v AC adaptor...I'm assuming this is the socket for plugging the power supply into?  And where can I get the Adapter?

What kind if shielded cable should I get?

What's the best sounding tube?

Thanks,

Scott

Grizz

one more question...When I print the pcb layout for transfering to the raw copper board for etching, do I resize it or do I assume it's already the proper size?

Scott

Mick Bailey

There are two ways to get an AC adapter - either buy one from a parts supplier that fits the description, or if you're confident, buy a DC adapter that has screws holding it together and remove or bypass the rectifier/smoothing components.

Either way, you don't want much more than 300-400 ma. The open circuit voltage of these adapters is often in excess of 14v and if the current capacity is too high (say, 800ma) you'll get too high a voltage for your tube as the supply won't be loaded enough. If this is all you've got, something like a 10 ohm resistor in one leg of the heater supply will bring it down. You need 12.6v ideally on the heater.

I used some shielded cable for mine which is about 2.5mm outside diameter with a single core. You only need thin stuff for wiring pedals up internally. Note that to avoid ground loops (and generating more hum) you only need to ground one end of the screening - the other end can be cut off flush.

The best tube I've found is an old Mullard ECC83 pulled from a Grundig tape recorder. The nice thing about this design is it's tolerant of a wide range of types. the new Sovtek 12ax7 gives very good results with high-ish gain, good saturation, smooth highs and tight bass. I tend to swap around quite a bit according to the style I'm playing.  I also use 12au7 and 12at7 for good bluesy sounds. Mainly pulls from old equipment which I 'audition' in my pedal. I recommend mounting the tube so it's accessible outside of the box so you can play with tube types more easily. Recent posts should give you some ideas.

Grizz

does anyone know of any suppliers for ac adaperts?

Pushtone

Quote from: Grizz on April 10, 2008, 01:34:03 PM
does anyone know of any suppliers for ac adaperts?

That depends where you live.
Most electronic suppliers will carry a range of AC and DC wall warts with different voltage and current outputs.
Here's one



But before you go on-line for one have a look around your house, flea markets, etc for one.
I used the power adapter from a bubble toy my kids don't use.

BTW, are you going to use Paul's layout in a 1590BB?




Hey Mick,

You described the my exact experience with the Skaka Tube power supply.
My adapter says INPUT:120VAC, OUTPUT: 12VAC @ 850mA.
I metered exactly 14VAC with and without the load on it.
Yourself and Paul M helped me out debugging that and indeed I used a 10 ohm (5w) ceramic resistor to drop the AC voltage going to the tube heaters to 12VAC.
The power board seems to be happy getting the full 14VAC and produces around 13VDC for the opamp.

Dave
It's time to buy a gun. That's what I've been thinking.
Maybe I can afford one, if I do a little less drinking. - Fred Eaglesmith

aron

Radio Shack has them too.

Grizz

How do you post a picture?


I'm talkikng about the female socket that you plug the power supply into...can I use just the same socket you use for a 9volt FX?

aron


Grizz

BTW, are you going to use Paul's layout in a 1590BB?

No I'm going with a bigger enclosure.

Mick Bailey

Before you build, take a look at Dave's Shaka Tube - IMHO this is the best looking tube pedal out there, DIY or commercial. Wish I'd seen this before building my own.

http://www.diystompboxes.com/smfforum/index.php?topic=66729.0

Paul Marossy

I got my AC adapter at a thrift store for 50 cents.  :icon_biggrin:

aron

I never thought of lower the tube using standoffs. I simply used the tube shield to protect it.

Grizz

Mick thanks for the link...I'll take others if you got'em.

Grizz

Mick Bailey

Another Shaka tube with the tube on the outside (scroll about two thirds down). Don't know what the extra knob does, though. With my own build I ended up going with Aron's suggestion of using the screening can to protect the tube, but it stands a little tall so I might try cutting the can down some and shortening the spring. It does work to protect the tube, however.

I do like the recessed version, especially with the LED adding to the glow of the tube and intend to build another using this method.

http://www.beavisaudio.com/older.htm

Pushtone

#14
OK Grizz,

You might want to look at another tube build I did...
link

Here's the associated thread.
http://www.diystompboxes.com/smfforum/index.php?topic=62049.0


I used standoffs to mount my tubes too.
Even doing that it still sticks up a little above the roll bar.
And it's a PITA to get them screwed in.

I'm very lucky to have access to a set of Green Lee punches to make the holes for the tubes.
Without it I would have made a huge mess out of the box.

It's time to buy a gun. That's what I've been thinking.
Maybe I can afford one, if I do a little less drinking. - Fred Eaglesmith