Tube boost + overdrive running off a 9 volt battery

[Renegadrian]

I turned the Gain all the way up and there is some overdrive there, so it does work after all!  I've spent most of my day reading that Valve Wizard site - definitely going to pick up the book I think.

Are there any DIY tube distortion pedals around?  I'd imagine they'd probably need a DIY power supply to go with them, but I don't mind building one of those as well.

Are you looking for more gain?! Try my Tube Star!
http://www.diystompboxes.com/smfforum/index.php?topic=74888.msg610047#msg610047

[BigBadDom]

Can't see the Tube Star schematic as the site is blocked by our server at work.  I'll have to have a look at home.

The Valvecaster seems to have loads of clean boost, presumably as a result of the 2nd stage so there's plenty of oomph available (the obvious limiting factor running off 9 or 12v).  I wonder if there's a simple way to drive the 1st stage harder and the 2nd stage not so hard to provide a bit more crunch but with less clean headroom?  Would a 12A?7 valve with more gain spice things up?

Just ideas at the moment - I've asked santa for the Valve Wizard's book!

Dom

[WhenBoredomPeaks]

I turned the Gain all the way up and there is some overdrive there, so it does work after all!  I've spent most of my day reading that Valve Wizard site - definitely going to pick up the book I think.

Are there any DIY tube distortion pedals around?  I'd imagine they'd probably need a DIY power supply to go with them, but I don't mind building one of those as well.

Are you looking for more gain?! Try my Tube Star!
http://www.diystompboxes.com/smfforum/index.php?topic=74888.msg610047#msg610047

Hi! I thought about doubling your Tube Star circuit and use it as a high gain preamp.

I have two questions:

Where should i put the tonestack? Between the two stages (i mean between the two Tube Star circuit) or at the end of the circuit?
(i bypassed the tonestack in my amp, its like a Vibro Champ or Tweed Champ now)
Resistors are normal 1/4W resistors with 50V B+ or they should be more powerful at some places like the cathode resistors?

[REGNAD]

i tried a 12ax7 in mine and it sounded bad. much less volume. over all bleah...

[WhenBoredomPeaks]

editfail

[KH602]

Instead of bulding a 12V power supply for the valvecaster or dual valvecaster, is there one you can buy with the right volts and amps ratings? i am only asking as i am not sure about building them.

[Renegadrian]

Hi! I thought about doubling your Tube Star circuit and use it as a high gain preamp.
I have two questions:
Where should i put the tonestack? Between the two stages (i mean between the two Tube Star circuit) or at the end of the circuit?
Resistors are normal 1/4W resistors with 50V B+ or they should be more powerful at some places like the cathode resistors?

Didn't try the double star, let me know if it turns out well!!! I'd put the TS as you say, between tube A and B.
It seems that 1/4 W res handle fine the voltage - it's not high enough to need other types!

-

REGNAD I tried an AX7 too, the result was awful.

[Ripthorn]

Instead of bulding a 12V power supply for the valvecaster or dual valvecaster, is there one you can buy with the right volts and amps ratings? i am only asking as i am not sure about building them.

Any 12V power supply with at least 200 ma for the valvecaster or about 400 ma for the twincaster should be fine.  It may require extra filtering if it isn't already filtered, but that is easy.  Also, make sure to note the type (center positive or center negative) and wire accordingly (most stompboxes are center negative).

[KH602]

Instead of bulding a 12V power supply for the valvecaster or dual valvecaster, is there one you can buy with the right volts and amps ratings? i am only asking as i am not sure about building them.

Any 12V power supply with at least 200 ma for the valvecaster or about 400 ma for the twincaster should be fine.  It may require extra filtering if it isn't already filtered, but that is easy.  Also, make sure to note the type (center positive or center negative) and wire accordingly (most stompboxes are center negative).

does it matter how much current runs through it? eg. max current through valvecaster & dual valve?

[REGNAD]

big misunderstanding wih current. current is the flow of electrons, or electricity. a power supply is given a rating of lets say 12vdc at 500 milliamps. it delivers 12 volts and can dwlliver up to 500 milliamps. the load is only going to take what it needs. in other words, you could have a 12 volt 15 amp power supply and the load (the tube circuit) is only going to draw the amperage it needs, nothing more. hope that helps.

[mmaatt25]

Hi,

I replaced the 12AU7 I had in my valvecaster for a 12AY7 in the quest for a little more gain/drive. There is definitely more gain/drive not as much as thought I would get bearing in mind it should be double the the gain according to the figures (12AU7 gain 20 & 12AY7 gain 45). What i did notice more was the volume drop using the 12AY7. Unity on my setup with 12AU7 was 9 oclock with gain at 12 oclock, but with 12AY7 unity was 12 oclock with gain the same at 12 oclock.

Has anyone else noticed this volume drop??

Many thanks

Matt

[Ripthorn]

This volume drop is not an uncommon thing with tubes.  This is what happens when tubes with different characteristics are put into the same circuit.  IN order to take the biggest advantage of a higher gain tube, you have to change cathode and plate resistors, bypass caps, etc.  Hope that helps.

[KH602]

big misunderstanding wih current. current is the flow of electrons, or electricity. a power supply is given a rating of lets say 12vdc at 500 milliamps. it delivers 12 volts and can dwlliver up to 500 milliamps. the load is only going to take what it needs. in other words, you could have a 12 volt 15 amp power supply and the load (the tube circuit) is only going to draw the amperage it needs, nothing more. hope that helps.

Thanks very much. just wanting to confirm things thats all. I have a 12V 2A supply lying around thats all. I just got my tubes today for it. Is it possible to dual valve an 12AU7 & 12AX7 in the dual valve circuit on here?

cheers

[Ripthorn]

12ax7's tend to sound nasty when used in starved plate mode.  What are you trying to achieve?  If you want more gain, go for a higher voltage.

[KH602]

12ax7's tend to sound nasty when used in starved plate mode.  What are you trying to achieve?  If you want more gain, go for a higher voltage.

what kind of high voltages you talking about? reading this forum, i thought higher than 12V would lower its life exspectancy, but then again thinking about high powered heads like peavey & marshall they would use a lot more than 12v. when i got my 12AU7 valve i didnt think it would be that small due to looking at the valves in amps etc.

[Ripthorn]

You are thinking of the heater voltages, those are the same.  THe plate voltages are what I am talking about and those govern how the tube reacts to an incoming signal when coupled with thing slike the plate and cathode resistors, etc.

[BigBadDom]

I removed the gain pot (it's always maxed out) and the tone pot and cap (i don't use it).  Seem to have just a smidgeon more gain and just starting to get some crunch.   

[Ripthorn]

I removed the gain pot (it's always maxed out) and the tone pot and cap (i don't use it).  Seem to have just a smidgeon more gain and just starting to get some crunch.   

It's not just you, you are getting more gain.  That is because the cathode of the first stage is now completely grounded and there is not signal at the tone stage going to ground.  I have a twincaster I'm working on, just need to pull it out and get it together.

[Arlaharen]

So I just stumbled upon this thread which is extensive to say the least.
To sum up this is what I would like to do:

I'd like to build a tube boost using this technique (after reading up on en 12AU7 6111 Valve Caster Summary PDF):
http://www.beavisaudio.com/projects/ValveCaster/MatsuminValveCasterWiring.gif
But using 12v (since most people seems to prefer it) and adding a 7812 and a 100uF filter cap on the dc jack to eliminate hiss.
Which components are preferred if I want a subtle and sweet overdrive sound?

I'm a bit new to all this, but I can follow a diagram...
Could someone please supply me with a BOM?
A revised wiring diagram (with the above mentioned additions) would be great as well...


Best,
Arlaharen

[Renegadrian]

At page 69 you got a good layout!