Tube boost + overdrive running off a 9 volt battery

[iccaros]

I actually just used Frequency Central's awesome super simple submini pentode boost here: http://www.diystompboxes.com/smfforum/index.php?topic=70524.0

And as far as loading, I'm not sure I follow... This is my first build with tubes, and I'd love to learn more, so let me know if there is a better approach than this!
Here's a diagram:

Guitar input --> true bypass switchable pentaboost --> true bypass switchable valvecaster --> guitar out

So the way I've done it was just what seemed to be a simple way of having either, both or neither engaged at once.

Is there a better way?

That tube wants 20K for load resistance, which means you get less power out as you are not drawing current to spec.. The volume pot should act as the load, but I think these should be 1meg not 100K, but I am willing to hear other thoughts on this. It seams that 100K is sensitive to what else comes after it.
But I don't think at these voltages you are going to hurt it, but I am interested in other thoughts.



I just "Won" (14)  5902 submini pentodes. They have a rating of 1 watt clean and 4 watts dirty. I was going to try and make a AX84 HO with them and some 6111's I have...  but this could be a good project for one of them.

[Ratbones]

To my ears it sounds quite nice, but if the load being under spec is harmful to the life span of the tube, then I wonder if I should look into balancing the load out...

[iccaros]

To my ears it sounds quite nice, but if the load being under spec is harmful to the life span of the tube, then I wonder if I should look into balancing the load out...

Since the tube is running in a starvation mode, I don't think it matters. But Its a question I ask even with the 12AU7, it want around 6K and the design has a 100K pot.

[Death Super Mario]

I don't know where to but led, 9v adapter and how to connect 9v battery socket and 9v plug.
I have 2 way tumbler with 2 legs and 3 way tumbler with 3 legs.

Another problem is that I wanna but tub inside metal box for safe.
I don't know how to do it.

[Renegadrian]

also you want but write english.
you don't know how to do it



ah ok but is put - now makes sense...

[zambo]

how are you going to use this pedal? If you are going to switch it on and off while playing then you need to use at least a dpdt stompswitch. For an led you should probably use a 3pdt switch. the wiring diagrams are on this thread for that multiple times. just do a quick search and you will find it. To mount the tube inside, use a pcb mount tube socket on perf board and a ribbed box ( for your pleasure ) and moun the board in the box. Or you can take an L bracket or bent sheet matal, drill a big enough hole in it to mount a normal tube socket and mout the bracket to the inside of the box. Renegadrian has the easiest vero board layouts to follow and they work well consistently if you follow them. Good luck and post results!

[iccaros]

I don't know where to but led, 9v adapter and how to connect 9v battery socket and 9v plug.
I have 2 way tumbler with 2 legs and 3 way tumbler with 3 legs.

Another problem is that I wanna but tub inside metal box for safe.
I don't know how to do it.

Once the heaters are on, this tube gets warm so if you want it in the box, drill air holes or give it some space. The heaters dissipate almost 2watts of heat..

[Ratbones]

Hey guys, I've got a successful (mostly) well operating build now... It's a valvecaster w/ a switchable 5672 submini preamp. 

First of all, it's kind of noisy... 60Hz hum, you know. Probably the wall wart I'm using is unregulated. That's not really the weird thing; what IS weird is that when I run that unregulated 12v 800ma wall wart thru a simple rc filter in a little box I made a while ago, the valvecaster/preamp fails to operate AT ALL. Measuring voltage straight from the wall wart I get somewhere around 16v. Measured from the jack on the little rc circuit, it's about the same... measured immediately from the dc jack on the valvecaster, I've got really low, like 3v low, voltage... What could be up with that!?  The V.C. works fine straight from the wall wart.  Is the RC circuit consuming so much amperage that the voltage drops that much?

[Govmnt_Lacky]

Is the RC circuit consuming so much amperage that the voltage drops that much?

That depends.... is there a TO-92 voltage regulator in your RC circuit?

If so, then you should consider swapping it out for the TO-220 series that is rated (usually) at 1A. The TO-92 series regulators are only rated (usually) to 100mA.

[Ratbones]

Thanks for the advice Gov. Lackey, but after a bit more experimentation, I seem to have figured out the source of my frustrations! First off, something in my house's mains at that outlet gets buzzy every now and then apparently... So most of the noise was due to that.

But! Most importantly... I retraced my schematic to see if I had done something wrong with the submini... turns out that I had decided to connect the b+ connections straight to the + dc so that my wall wart's 16v of preregulated would go to providing more clean headroom. So, on a hunch, I cut that connection and tapped the b+ connection of the 5672 circuit to the output of the 7812, and voila. No more noise. At all.

Turns out, at least in my experience, that b+ regulation via a 7812 or LM317 does go toward filtering out noise.  Thought that might be useful to someone else in the future

[iccaros]

Thanks for the advice Gov. Lackey, but after a bit more experimentation, I seem to have figured out the source of my frustrations! First off, something in my house's mains at that outlet gets buzzy every now and then apparently... So most of the noise was due to that.

But! Most importantly... I retraced my schematic to see if I had done something wrong with the submini... turns out that I had decided to connect the b+ connections straight to the + dc so that my wall wart's 16v of preregulated would go to providing more clean headroom. So, on a hunch, I cut that connection and tapped the b+ connection of the 5672 circuit to the output of the 7812, and voila. No more noise. At all.

Turns out, at least in my experience, that b+ regulation via a 7812 or LM317 does go toward filtering out noise.  Thought that might be useful to someone else in the future

the 7812 and LM317 are rated for 80db of ripple rejection, but I would not rely on that.

[Ratbones]

For what it's worth, that suppression made a huge difference in my pedal.  It's pretty much noise free now, where as before it was almost unusable because of that noise.  I'm sure with a decent, well regulated wall wart it probably doesn't matter at all, but mine was a dollar from good will, and it sounds like it haha

[iccaros]

For what it's worth, that suppression made a huge difference in my pedal.  It's pretty much noise free now, where as before it was almost unusable because of that noise.  I'm sure with a decent, well regulated wall wart it probably doesn't matter at all, but mine was a dollar from good will, and it sounds like it haha

I under stand, I have a well regulated power strip from APC... So all of my pedals and amp are quite..
Plus I get all my wall warts from Good will now.. Using a Compaq Laptop 24V for my current project.

[Death Super Mario]

I soldered my valvecaster. I used beavisaudio less wiring diagram.
http://imageshack.us/photo/my-images/18/valvecaster.jpg/

I have to solder 9v battery and 9v adapter plug. My be led too.
I need to work on metal box.  I thinking to isolate the box with electrical tape. 

[iccaros]

I soldered my valvecaster. I used beavisaudio less wiring diagram.
http://imageshack.us/photo/my-images/18/valvecaster.jpg/

I have to solder 9v battery and 9v adapter plug. My be led too.
I need to work on metal box.  I thinking to isolate the box with electrical tape. 

No need to Isolate.. The metal Box is your ground....

[Death Super Mario]

Metal is good electricity leader.
I had small PCB board guitar effect. One corner contacted with metal box
and it melted some parts on board.
I wanna put tube inside the metal box.

To  I need to cover soldering points ?
Is electrical tape good for covering ?
I only have simple soldering iron with plug.

[iccaros]

Metal is good electricity leader.
I had small PCB board guitar effect. One corner contacted with metal box
and it melted some parts on board.
I wanna put tube inside the metal box.

To  I need to cover soldering points ?
Is electrical tape good for covering ?
I only have simple soldering iron with plug.

For this project, if you are using a PCB and not direct to the sockets...
Then Heat Shrink on all wires (use anyways)
Heavy construction paper (so it does not rip) attached to the bottom. So you have your post, cut a piece of paper the same size as the board, place board over post, then put in screws...

With heat electrical tape will come off. Paper burns @ high temperatures, well if your pedal got hot enough to set paper on fire, your guitar cord would have already started to melted.

[Death Super Mario]

I soldered directly to the socket.
http://imageshack.us/photo/my-images/18/valvecaster.jpg/

[zambo]

at 9 to 12 volts these tubes dont get that hot. I put one inside a box with minimal venting and it was fine. Just stop it from shorting out. I mount the tube socket to an L bracket and mount the bracket to the box. Its pretty easy. I actualy put 3 tubes together in one box that way. No problems.

[iccaros]

I soldered directly to the socket.
http://imageshack.us/photo/my-images/18/valvecaster.jpg/

You could use heat shrink, you can get large diameter at a Auto Repair place.  I have some that will go around a 8 pin Octal, so it would easily cover everything..   

while 12AU7 and 12AX7 do not get hot, others do, Well my 12AU7 got really hot, but I learned after wards that my LM7812 went bad and I was putting 30 volts on the heater