Valvecaster Tutorial?

[bennerman]

Are there any start-to-finish valvecaster tutorials? I just can't get these electrical schematics

[Elijah-Baley]

Of course you can get the schematic, but could there's no tutorials, maybe some reports or some variations end mod and advices.

If this is your first pedal you should read some generic guides about "how to build pedals".

Good luck! 

[bennerman]

I meant "get" as in "understand" xP

[GibsonGM]

On how to build it, or how it works? 

As for both, you will be FAR, FAR better off in the long run if you take a little time to learn more about schematics!  I can't tell you how much you'll be glad you did later, as you can never understand how things work if you don't!   It's not that bad, really!

Learn what symbols mean 'resistor', 'capacitor', 'diode'...look at the symbol for a tube, and note that each element goes to a pin...transistor, battery, ground....that really IS all there is to it.  It is as simple as wires connecting the parts, on the schema and in real life.  But you have to work a little for things you want!

After you do this, you will see the same patterns over and over, and know what they do.  So when you have an error, you'll have some very good ideas of where to look for the trouble.  That's why we all write back "can you post the schematic?".

You can do it.  You can start very simply, by just getting LEDs to light and making voltage dividers. The net if full of thousands of basic tutorials!

[bennerman]

On how to build it, or how it works?  

As for both, you will be FAR, FAR better off in the long run if you take a little time to learn more about schematics!  I can't tell you how much you'll be glad you did later, as you can never understand how things work if you don't!   It's not that bad, really!

Learn what symbols mean 'resistor', 'capacitor', 'diode'...look at the symbol for a tube, and note that each element goes to a pin...transistor, battery, ground....that really IS all there is to it.  It is as simple as wires connecting the parts, on the schema and in real life.  But you have to work a little for things you want!

After you do this, you will see the same patterns over and over, and know what they do.  So when you have an error, you'll have some very good ideas of where to look for the trouble.  That's why we all write back "can you post the schematic?".

You can do it.  You can start very simply, by just getting LEDs to light and making voltage dividers. The net if full of thousands of basic tutorials!

I am trying to learn. One thing I didn't understand is, on the schematics, it shows all the grounds going down to the bottom of the page. But unless they're connected to the case itself, surely there must be something else to which they are connected?

Sorry, I really really am the definition of a slow learner

[peterg]

All points indicated by a ground symbol on a schematic are connected. For the Valvecaster Beavis Audio has diagrams showing how to build one:

http://www.beavisaudio.com/projects/ValveCaster/

It's a pretty simple build since there are only a few components. For pedals the input jack typically is the ground connection since it is connected to the box.

[GibsonGM]

^  Nice; that's laid out well, should be easy to build.     Yes, the grounds are drawn "all over the place" sometimes, just to keep from cluttering up the schematic. They all run together.  If you put it in an enclosure, typically the input jack is where they 'come together' (from the circuit board and battery) as Peter said.  They are typically done 'neatly', to minimize noise, but that's another whole topic ("Star grounding").  For now, getting them from whatever you build on (circuit board...) to the jack + battery is the place to focus.

You just have to start small, and work your way in...after being able to read them and build the thing on a breadboard or what have you, then you learn about the switch and jack connections....break it up into topics/sections like that, it makes it easier

Other common points shown by more than one connection on a schema can be "Vref" (reference voltage), or power, just shown as "+", etc.  They only do it to save space and make the drawing more clear.

[bennerman]

Will this work as a pre-amp for my audio-interface as well?

[GibsonGM]

Depends on what your interface is, Bennerman...I think you'll want to pay CLOSE attention to the maximum output of this thing, if you were to connect it to a computer sound card or something like that.  If you have something that can only take a 5V input, you might get close to exceeding that limit.    So do your homework, and measure the output of the VC....remember that if your meter is RMS, your peaks will be higher...

You can limit the output, obviously, using the volume control, and for safety you can install a couple of zeners in the 'typical distortion clipping config' (parallel to ground from output) to clamp the voltage if it exceeds whatever you set for safety.   

If you get it built well, and enclose it so it's quiet, there's no reason this wouldn't make a pretty good tube preamp....I'd think of it more as a 'signal conditioner' or something, and it's not fancy, but it IS 'real tube' 

[bennerman]

Depends on what your interface is, Bennerman...I think you'll want to pay CLOSE attention to the maximum output of this thing, if you were to connect it to a computer sound card or something like that.  If you have something that can only take a 5V input, you might get close to exceeding that limit.    So do your homework, and measure the output of the VC....remember that if your meter is RMS, your peaks will be higher...

You can limit the output, obviously, using the volume control, and for safety you can install a couple of zeners in the 'typical distortion clipping config' (parallel to ground from output) to clamp the voltage if it exceeds whatever you set for safety.  

If you get it built well, and enclose it so it's quiet, there's no reason this wouldn't make a pretty good tube preamp....I'd think of it more as a 'signal conditioner' or something, and it's not fancy, but it IS 'real tube'  

It's a behringer UCA222. It's designed to take a behringer V-amp 2/3 preamp

Edit: Hmm, Where's the power supply in this diagram?

[GibsonGM]

I'm going to say they never planned it to run off a 9V battery, which would go flat in about 12 seconds considering the heater draw, ha ha...so the jack IS the power supply...plug in a 9V wall wart, away you go.  Make sure the wall wart is center negative!

You can see where R3 goes across pin 5 to the plate (pin 6) - that's where the circuit itself picks up power.  Pins 4+5 are the heater.

[bennerman]

Oh, the thing on the top left is a power input? I thought it was the on/off button

[GibsonGM]

Nah, that's a jack to plug in a wall wart.  You can use any kind you like, as long as you be SURE the "+" is going to pin 5 and the  "-" to pin 4. 

Note that the guitar jack just below it (1/4" stereo TRS jack...it's the input) switches the ground, so the power goes off if you unplug from it.   You don't need the power jack - you can just hard-wire it if you like, but that's inconvenient and may cause you to short it out by accident, being sloppy and all....

[bennerman]

when you say "wall mart", do you just mean a generic 120v-to-9v adaptor that you can get anywhere?

[duck_arse]

[psssttt! Gibson! those jacks show only tip and sleeve, no switch action.]

as for the power supply 120V-9V DC. must be dc. generic DC, but DC all the same.

[GibsonGM]

Ha ha, didn't catch that. Sometimes I'm thick, DA!   Get focused on being sure he gets his power right and all that.  Duh.

Yes, you'll want the 9VDC wall wart.   If it buzzes when you use it, we'll cross that bridge then  

[bennerman]

Alright, and where can I get the actual plug/input for the 9volt? Should I just be able to find it at radio-shack/an electronics hobby store?

[GibsonGM]

Sometimes Rat Shack has them, but I get mine from Small Bear, affiliated with us here on the site. 
I like the 2.1mm plastic type:  http://smallbear-electronics.mybigcommerce.com/dc-power-jacks-1/