Tube boost + overdrive running off a 9 volt battery

[merlinb]

Ok. I have spent the last 2-3 hours combing through this thread and I still cannot find any layout/wiring info for a 12AX7 tube!
Can someone point me in the right direction? Did I miss some info in this thread about using the AXs?

To use a 12AX7 the pin out is the same, but you will want to move R1 and R4 (the grid leaks). Instead of connecting them to ground, connect them directly to the 9V supply.

(You may also want to experiment with connecting just one of them to 9V, the other to ground as normal).

[served]

I can say now that you can use
Russian tubes

6H1П-l(12AU7 and 6H2П(12AX7)
They work just fine.
6H2П gain factor is 100
6H1П gain factor is 35

But! Be Aware! 6N2P heater votalge is 6.3V, its filaments are connected paralel, so you cant just replace 12AX7 with this one.

[kaalaraab]

Hi, 1st post. I've read this thread back and forward and I've decided to build a Twinvalvecaster first  and a Trivalvecaster second. Next weak I'll buy the tubes, I have all other stuff. I'm pretty sure that I'll have many doubts in the process but I'm confident in this forum. First doubt   I have an old PS Input: 120V AC 60Hz 15W Output: 9V DC 1Amp Well, at least that's what it says, but it throws me an output from 13.27 volts to 13.31 volts. Do you think I can use it to feed my valvcaster? If not, I'm really decided to build my own PS too.

Wish me luck.  



"Those who fear darkness have never seen what light can do."

[zambo]

9 volt 1 amp dc should work if its filtered well. Dual casters are cool. Tricasters are sweet too. Good luck! If you read this forum all the way through you know all there is to know about these things!

[served]

Output: 9V DC 1Amp Well, at least that's what it says, but it throws me an output from 13.27 volts to 13.31 volts.

Hi.

The reading you get is not the real output, it is Electromotive force. You will need to use somekind of load to measure how many voltage it gives. For example, build the pedal and power it from this adaptor and then measure the voltages. Your adaptor will give 9V if the flowing current is 1A. If its less than 1A then the voltage is higher. If its higher than 1A, then the voltage is lower than 9V.
There are some IC controlled adaptors also. Their output is regulated to only give the voltage that is written on the package.
Just for information.

Good luck!

[Dongle]

Hi!
Did anyone try higher voltages than 18 V DC? Of course not for the heating, just for the rest...
Does it makes sense? How does it sound?
I dont like so much, that the sound is a bit "muffy". Would it get better with 18 V? So far, I am running with 12.
Regards
Dongle

[zambo]

Hi Dongle, I have one running at 63 volts and it sounds great. One of the characteristics of starved plate designs like this is an abundance of bass and treble with a huge cut to the mids. So if you wanted to counteract that you could always use a smaller input cap like a .002 or .003uf for caps 1 and 2. I have used .001 as well. I put them on a dpdt toggle so i have a fat and skinny switch....otherwise...yes raising voltage gives more mids and "balls" . I have a 3caster ( I call all mine Voltron ) running on 45 volts as well. I love it. You have to tame the highs between stages. I throw a .0005uf from anode to ground on all the stages. remeber to use caps and resistors rated for new voltage requirements! Hope that helps. Oh yeah...above 30 or 40 volts doesnt seem to make a huge difference in sound. I am starting to run them at 150 and 200 volts so I will post results when I get some done. 

[Dongle]

Thanks for that detailed answer! My english is notgood, so I have to ask again, although you wrote it:
What does it mean "above 30 or 40 V doesnt seem to make a huge different in sound"? Does it mean it is the same if I use 30 or 90 V? Would I hear something if I go fom 12 to 18 V, or should I try to make the big jump to 40?
The problem is; I cannot find DC power supplies with hogher voltages than 24 - and these are seldom as well! Could I use one of the ICL7660 to double the voltage? But they only work with AC and are not so powerful I guess...

Could you post your powersupply and Valvecaster-schematic? That would be great!!

For the resistors and caps: I just have to raise the power the resistor can consume, right? The values stay the same, right?

[served]

He ment that 30V and 40V sounds the same. If you go 90V then it will make a difference.

If you cant find DC adaptors, then use AC and rectify it with diodebridge (4 diodes and a cap)
Resistors may stay same, caps have voltage limitation.

[Dongle]

Thanks!
So I really want to try it with higher voltage...
Of course the heating remains at 12 V.
But how much power should my supply have for 30 / 60 / 90 Volts? If I understand it correctly, not very much... but I am not sure about this... Can someone tell me, the mA or Watt - number?
CU
Dongle

[merlinb]

But how much power should my supply have for 30 / 60 / 90 Volts? If I understand it correctly, not very much... but I am not sure about this...

Most of the current is for the 12V 150mA heater. You only need a few extra milliamps for the anodes / LED. 200mA would be more than enough.

[zambo]

Hey guys, Sorry for my absence, I have been working hard on a new project......more on that later! I use a voltage multiplier that i found on the Murder One thread by Frequency Central. It works quite well and the schematic is on there. I am using the ic from small bear that is marked lt1054cp . Like this alot and it has enough juice to run the 3 tubes anodes easily. I dont have a schematic for the Voltron pedal ( triplecaster ) but its pretty easy. Chain three valvecasters in series and change all the input caps ( cap 1and 2 ) to .002uf. thats a good start. At higher voltages i have found that putting a .0005uf (500pf) from anode to ground stops some of the oscilations. I am not an experienced preamp designer so do this at your own risk. for real! If merlinb or anyone else wants to offer advice...take it. They are smart.PM me if you need to get ahold of me faster as this sight only notifies me of private messages. Good luck! G

[Dongle]

Thanks!
I will try higher voltages, as soon as I manage to implement them
I am looking forward to it - and hope for a better sound...
Cheers!

[jrmcgrath13]

Here's my layout that I made when I built my triplecaster: http://jrmcgrath.com/images/triple%20valvecaster.jpg.

It's not the most "proper" of layouts, but it worked.  =]  I think I have the resistor on the master bypass LED on the wrong lead though.

[Mfouch]

So many pages on this topic I don't know if this has been covered sorry if it has. IS there a way to convert this to a clean boost I've been experementing a little but cant get it right. Thanks for the help

[zambo]

I hear if you change the plate resistors too a lessor value it makes it cleaner. Change r2 to a 100k and see if that helps you.

[Mfouch]

thanks is there a way to get rid of the gain knob i could replace with 50 k resistor but wouldn't that just keep the distortion in?

[zambo]

no it sets the "bias" so that the tube would run cooler. Straight to ground is max distortion. I would go about 25k if I went that route.you probably want some gain. Actualy the option of the knob is nice I think.

[Mfouch]

yah ill probably keep it in but I'm looking for a clean boost to run into a solid state frontman and to boost my strat into some distortion pedals.  sorry one more question if i raise the 1uf cap will that raise the volume also sorry I'm slowly figuring all this out and thanks for the help.

[zambo]

no apologies needed man, we are all friends and everyone here is really helpful to everyone else from what i can tell.Raising the 1uf cap wont change the volume as far as I know. I believe it blocks the dc from leaving the pedal while allowing all the guitar ac frequencies to pass. Raising the plate voltage dramaticly increases volume. Are you running nine or twelve volts? If you are rtunning either one and want more volume, take a lead from the dc input to run the heaters only. Take another lead from the dc in and run it into a voltage multiplier and run that on your plates. 18 or 24 volts will give you ample volume and you will here an improvement in the mid frequencies as voltage goes up. Voltage multiplier I use is on the Murder one thread started by frequency central on this forum. Its cheap and works well.