Delay and a Tube Box

[MetalUpYerEye]

Howdy guys! I'm wondering about building an overdrive box that works with a real tube. Kind of like the tube-preamp in the Marshall Valvestate amps. Anyways, I did a little research but couldn't find anything that works off a 9v power source... Any help?

My other question is about a delay. I'd like to build one but haven't found much info on them here. Are they difficult? Any suggestions?

As always, thanks a lot.
Josh

[zpyder]

My other question is about a delay. I'd like to build one but haven't found much info on them here. Are they difficult? Any suggestions?

I recently put together a Rebote 2.5 Delay.  I would definately suggest it.  Though I've played it very little I can tell you it's a very slick little unit.  The Rebote 2.5 is probably one of the simplest delays out there, though delays tend to be a bit more complex in general.  I created a layout for it (and posted a shot of the board) at http://aronnelson.com/gallery/rebote25.  The layout is pretty crowded so that it will fit onto one of Aron's smaller perf boards that are for sale.  The original schematic is from tonepad, and they have a PCB layout for it if that's more your style.

Important note: I, as well as another person, experienced a pretty complete failure of the unit when trying to use it with a battery.  With a 9v battery reading ~8.5v on it the effect straight up didn't work.  Plugged in my wall-wart PSU and everything is crisp as morning sunlight.  I haven't had a chance to test it with a 'fresh' battery, but it seems that the unit must draw quite a bit of current...

zpyder

[bancika]

what about shaka tube or tube driver? They work with bipolar +-12V IIRC, you'll hardly find some that works with 9V. I doubt that valvstate go as low as 9V. I was also trying to find valvestate schematic, but all valvestates I found were actually valve-less

[boogietube]

The Valvestate Series 2 amps have a single 12ax7 preamp tube in them. I own a VS100 -1/2 stack and a VS265 -212 combo.
As was mentioned the shaka tube is one.
www.diyguitarist.com has a shaka tube in a 1590bb project. A most beautiful project.
The adapter should be easy to get. Mode electronics distributes them   

[AdamB]

Valves don't operate very well at around 9V, they will work, but they really need a couple hundred volts accross them before the real magic happens. You can build preamps-in-a-box (look up the hotbox, I think there is some info about it on generalguitargadgets.com), but the better ones have there own power transformer to supply the B+.

Also, having a 9V supply is sort of pointless, as the main reason for this I would assume would be so that the device can run from a 9V battery. However, the tube heater filaments will drain the battery dead in a very, very short time (on a 12AX7 valve, they draw 250ma or so?)

-Adam

[Ronsonic]

As a general rule, any commercial product with the words "Valve" or "Tube" in the name aren't. Or they do something perverse like run the tube at 12 volts or use it as a diode like in some weird Fenders.

Ron

[frickecello]

Obviously you will need and external power supply to make a valve pedal work...

Ive built two valve pedals without modding them to hear the difference, they are the tube driver (schematic drawn by Jack Orman) and the famous Shaka tube (by legendary Aron Nelson), the first is very noisy and forget about switching to the high gain channel of your amp! also the circuit has some "old school" stuff (it has a unity gain buffer stage, output of final valve stage is not bypassed etc, etc, cathodes to ground without bias resistor and bypass capacitor, etc etc etc).....

The Shaka tube is a very simple and well designed circuit, (Aron deleted the buffer stage, the cathode is biased and bypassed, the output at the final valve stage is bypassed, you will need less components than the t-driver, its very quiet, etc etc) I like the Shaka..... but for my personal tastes I did the following mods:


++++ I didnt wanted any AC heater hum, so I added another dedicated power supply to feed the heaters with 12V but DC:

From the same wall wart 12AC supply I added 2 diodes to rectify, 1 2200 uf cap, 1 220 uf ap, 1 22 uf cap and finally a LM7812 voltage regulator to extend valve heater life...

++++ I didnt liked the trebly character it had so I tuned the input coupling cap and the tone pot section....

++++ I bypassed the volume control... its a common practice, and minimizes the chance of high frecuency noise....

[d95err]

Howdy guys! I'm wondering about building an overdrive box that works with a real tube. Kind of like the tube-preamp in the Marshall Valvestate amps.

The clean channel on the valvestate uses a tube to for the sound. The distortion channel uses opamps and clipping diodes. Think of it as putting a regular solid state distortion pedal infront of the clean channel. So, if it's the Valvestate dist sound you want, you may be better of just building a regular opamp based pedal.

http://www.schematicheaven.com/marshallamps/valvestate40_40w_8040.pdf

The Tube Driver and Shaka Tube are similar in the sense that a lot of distortion comes from the opamp, but at least they don't use clipping diodes.

[RaceDriver205]

I wouldn't bother building a tube distortion. I built a tube driver, and you may as well build a normal solid state distortion. I think perhaps that just coz it has a tube in it, doesn't mean you are going to get a sound anything like an all-tube amp.

[JimRayden]

I wouldn't bother building a tube distortion. I built a tube driver, and you may as well build a normal solid state distortion. I think perhaps that just coz it has a tube in it, doesn't mean you are going to get a sound anything like an all-tube amp.

Please don't let one project put you off and cause prejudices. The fact is, Tube Driver sucks. There are decent tube distortion pedals but they run on high voltages (like Hotbox and EH Hot Tubes, although the latter is in current production and no schematic is available) with a little exceptions like the Shaka Tube. Haven't built it but the sound clips are pretty darn good.

---------
Jimbo

[RaceDriver205]

Well to be fair, my opinion of distortions has been a while in the making, and that is that I think they all sound 'close enough' with the chief difference being the maximum gain. For the shear number of difference distortion making circuits people have made, they don't sound very different any of them. But thats just me. 

[JimRayden]

Well to be fair, my opinion of distortions has been a while in the making, and that is that I think they all sound 'close enough' with the chief difference being the maximum gain. For the shear number of difference distortion making circuits people have made, they don't sound very different any of them. But thats just me. 

Well, some are okay with a squier starter pack and some walk around a warehouse knocking on different pieces of wood listening to their overtones and delicately choosing which 1% film resistor to use in the pedal - the 1.542k or the 1.547k one.

Most of us are in between those though. Scattered all around the place, some hear the nuances, some don't. I am what one would consider cap-material-deaf. I just can't understand what people mean by ceramic caps adding more grit.

But the difference between a Fuzz Face and a Dr.Boogie is widely regarded as more than a nuance. Even at the same level of gain.

---------
Jimbo

[JonFrum]

Here's a tube preamp project from Hoffman Amps.

http://hoffmanamps.com/projects/tube_box.htm

[Pushtone]

The Real McTube


http://www.dogstar.dantimax.dk/tubestuf/mctube.htm


http://www.tonepad.com/project.asp?id=23


http://www.diyguitarist.com/DIYStompboxes/RealMcTube.htm


http://www.diystompboxes.com/smfforum/index.php?topic=41021.msg325009


http://amps.zugster.net/articles/tube-pedals/

[RaceDriver205]

But the difference between a Fuzz Face and a Dr.Boogie is widely regarded as more than a nuance. Even at the same level of gain.

Hmm, indeed.

As for those links, Ill do some listening to the Real McTube. I heard one clip of it once, and it sounded real bad, but mostly because of how the guitar was played.

[frickecello]

I think that first of all you have to know what you can expect from a valve pedal:

+++ If you like metal distortion or intend to get a modern metal distortion with tons of gain from just a pure valve pedal then get a jfet or jet+diodes (solid state) project....
....but if you like to use it as a preamp... and then switch to the high gain channel of your amp or before a high gain pedal, it is highly advisable because you will get valve mojo and lots of gain from solid state distortion (best of both worlds)

+++ Some people expect from a schematic to work and be perfect, and build it without studying it or without understanding how it works... most of the times you can do improvements, subtle or not, but they will certainly upgrade the original circuit...

+++ If you are not familiar with electric principles (mains wiring, how transformer works, etc etc) I advise you NOT to build a "high voltage" valve pedal...

+++ Electron emission is temperature dependent in a valve, and before worrying about if you will get tube sound or not from a "lo-volt" valve pedal, first build an adequate and regulated heater DC supply to run the heaters in parallel (6.3v) or in series (12.6v)

In my opinion you should first build a low voltage tube pedal like the Shaka Tube (forget about the tube driver), and hear it.... I think it is the only low voltage tube pedal project available that really works without any modification or correction to the original schematic....

Regards.

[JimRayden]

As for those links, Ill do some listening to the Real McTube. I heard one clip of it once, and it sounded real bad, but...

It does. 

Check out ax84.com, they have developed a few mods to make it sound more humane.

----------
Jimbo

[RaceDriver205]

Yeah, ive listened to some of the clips at the above links, and it SUCKS. I now have no interest at all in valves.

I think it is the only low voltage tube pedal project available that really works without any modification or correction to the original schematic

I actually was going to built the shaka tube, but I couldn't follow the layout, so I rebuilt a tube driver instead (doh!).

[fikri]

I would prefer the Westbury W-20 than the Real McTube. It is a one trick pony to use a clipping diodes for adding more gain from a single tube. I've also working on the Shaka-Tube now, I have the idea from Paul Marossy with his redesign of Shaka Tube in a smaller box. But i think my design is way smaller than his  http://fikri_ilyas.blogs.friendster.com/photos/new_project/