Tube boost + overdrive running off a 9 volt battery

[muckey pup]

voltages
using a raytheon 12AT7wb
at 9v
p1,       7.56v
p2,      -0.39v
p3,       0v
p4,       0v
p5,       9.3v
p6,       8.27v
p7,       -0.48
p8,       0
p9,       4.6v
and at 12v
p1,     9.79v
p2,    -0.65v
p3,    0v
p4,    0v
p5     12.33v
p6,     10.59v
p7,     -0.71v
p8,     0v
p9,     6.12v

the peddle is working but at 9v its a unbooster with less vol than bypass when all
pots at max
at 12v it is about the same vol ass the bypass with slightly more gain
there is no buzzing or poping and the led lights when peddle is on
led is supper bright dose this mater
i have removed the powre socket and its the same
am i expecting to Mitch boost from the pebble
the ones Ive seen on youtube seem to have a tun of boost

[muckey pup]

boom
i just tried a direrent tube (mulard 4024) and wow Babb
what a peddle
in to my mini mat it screams, and loads of gain and vol and
a real good eq  i need to start on a twin castert today
thanks every one who replyed
muckey pup

[muckey pup]

and a jan 5814a sounds amazzzzzzzing

[deadastronaut]

@muckeypup..

soundclips?..

[muckey pup]

dose Anny one know what these things are like on tube life
at 12 v or 9v
should i use my precious nos tubes or get some jj to burn?
ill do sound clips on tus afternoon as every one in my house is
already pised at the noise and ill need them out to crank some
of the amps
ill try it the mullard 4024 and jan5814a

[tasos]

hey...i have read that this circuit is also good with 12v...
i am thinking of building this with 18v...would this be ok or would this burn the tube?
also what current is this circuit ''eating''?

[zambo]

18 volts is fine for the anodes but not for the heaters. You would need to wire it so r 2 and r 3 are not connected to the heaters. They only want 12.6 volts max. otherwise yeah 18 volts sounds good and gives more volume boost and clean headroom. I like to run about 45 volts on pins 1 and 6. I knoe the heaters eat about 150 ma. the rest probably easts 10 to 20 i think.

[tasos]

18 volts is fine for the anodes but not for the heaters. You would need to wire it so r 2 and r 3 are not connected to the heaters. They only want 12.6 volts max. otherwise yeah 18 volts sounds good and gives more volume boost and clean headroom. I like to run about 45 volts on pins 1 and 6. I knoe the heaters eat about 150 ma. the rest probably easts 10 to 20 i think.

what pins are the heaters?
basicly what's up with the heaters?they pre warm the tube or something?
thanks!

[Govmnt_Lacky]

Could I run a charge pump circuit in PARALLEL with my 12VDC input so that I could

A) Power my heaters with 12VDC (with the direct feed from the DC jack)
B) Power my plates at a higher voltage from the charge pump
C) Still keep the the current draw below ~200mA since the power feeds are in parallel.

Am I correct?

[iccaros]

18 volts is fine for the anodes but not for the heaters. You would need to wire it so r 2 and r 3 are not connected to the heaters. They only want 12.6 volts max. otherwise yeah 18 volts sounds good and gives more volume boost and clean headroom. I like to run about 45 volts on pins 1 and 6. I knoe the heaters eat about 150 ma. the rest probably easts 10 to 20 i think.

what pins are the heaters?
basicly what's up with the heaters?they pre warm the tube or something?
thanks!

Heater make the tube work. A tube is a thematic device. Meaning with out heat it does not work. The heaters (filament) heats the Cathode, causing electrons to literary boil off. The grid attracts or repels the electrons, based on its charge.
copy this and put in your back pocket http://www.hnsa.org/doc/neets/mod06.pdf

as for voltage tube heaters are designed for 6.3 or 12.6 depending on how you run them. There are two in this tube, so if you run from pin 4 to pin 5 you are running both tubes one to the other.  each are about 42ohms (12au7) in resistance 12.6/.150 (important to know if you want to create a voltage divider to run the tubes, which I calculate to about 70ohms to get ~12volts from  wire Plu voltage 70ohm Pin 4  flows through pin 5 to ground ) . if you run from Pin 4  and Pin 5 to + voltage and pin 9 to ground you are running parallel and you will pull .300 amps or 300 milliamps

Tube heaters in most cases are rated at +/- 20%, but most  are not tested beyond +/- .6 volts. If you run at ~12 you will be fine. With lower voltage the tube will last longer but you loose performance, as long as you do not cause cathode striping.
Too high and you can burn out the heater coil.

[tasos]

oh this is great!
here is my though...could i run the tube with a voltage doubler and [18v] and the heaters with 9v ?

[iccaros]

oh this is great!
here is my though...could i run the tube with a voltage doubler and [18v] and the heaters with 9v ?

Heaters will work @9 but you risk cathode striping. you could run parallel heaters @ 6.3 volts. A 22 ohm resister should get you there.
When you run 9 volts each heater wire only get 4.5volts as they are in series.

So I would connect a 11.3ohm 1 watt resister to pin 5 and 4 and connect pin 9 to ground would get you 6.3 volts. a 10ohm would get you 5.8 volts (within +/- .6) 
                 10ohm 1 watt
+18volt ---WWW----(Pin5 & Pin4)
Ground ------(pin 9) 

If you change tube types this could change, calculate the resistance of the tube by calculating rated voltage/ rated current
so a 12AU7 says it is good in serial connection @ 12.6v drawing .150 amps (150 milliamp) so 12.6/.150 = 84 ohms. so in parallel they should be 21 ohms (1/ 1/r1+1/r2, plus they are the same value so the 84/#of resisters of the same value = 42 ohms each wire, so in parallel, like speakers that is 22ohms) but we also have the datasheet which tells up that a 12AU7 heater in parallel pulls .300 amps @ 6.3 volts so 6.3 / .300 = 21.

if you change tube types check the datasheet.
or you can put a 5volt regulator like 7805 by placing one or two diodes on the ground pin. The amount is based on the voltage drop of the diode.  This would work for all tubes, I attached mine to the case as a heat sink.

[tasos]

that sounds complex...do you think it is really worth it?
i am also thinking of adding a charge pump which would bring the voltage at 12v...so i follow the same schem with 12v...how about that?

[iccaros]

I am using 30volts, but I am using a 30vdc wall wart I got at good will for $2. I use a 12volt regulator on the heater, a 7812. Its simple power in, ground power out.. Just need to attach it to the cast to get rid of heat.  In mine I use the LM317 with 100ohm resister for R1 and 800ohm for R2. This way I can go all the way to 52 volts on the pedal, with no changes.

But in your case, If you want to go to 18 the single regulator is fine. you have to remember that the heaters pull 150ma alone. If you use a step up then you have to double that or more, so a voltage doubler you need at least 300ma to run your 150 ma heaters in series and .6 amps to run in parallel.

With this design the tube heaters are the most important to get right. 9 volts will work, just will in time kill the tube faster.


Remember that everything up to input I on the regulator is in the wall wart. You would also send point I to the rest of your design. The LM7812 is good up to 35volts I believe.

[iccaros]

in case some one wants to build this, it would not be 18volts after rectification. you have to multiply by 1.414 = ~25volts

[tasos]

i wanna power all my pedals with one power supply...this is why i am thinking about the voltage multiplier with a max1044!with a 12v regulator probably!

[Govmnt_Lacky]

i wanna power all my pedals with one power supply...this is why i am thinking about the voltage multiplier with a max1044!with a 12v regulator probably!

Just be sure to check the current requirements of the MAX chip. I believe it is down in the low mA when powered by 9V. It may run 1..... possibly 2 pedals but, I doubt it will provide enough current for more than that.

Good Luck 

[iccaros]

i wanna power all my pedals with one power supply...this is why i am thinking about the voltage multiplier with a max1044!with a 12v regulator probably!

Just be sure to check the current requirements of the MAX chip. I believe it is down in the low mA when powered by 9V. It may run 1..... possibly 2 pedals but, I doubt it will provide enough current for more than that.

Good Luck 

When powering multiple pedals it is better to start @ a higher voltage and divide or regulate down then to go up.
for instance, your tube draws 150 MA for heaters, if you up the voltage to 18 and then back down you would need at least 300MA for the same work. Since each part in between will have loss you maybe looking 600MA.
While if you create a ~25volt regulator and go down, you could feed 25v to the system and a 12volt regulator to each tube heater, or even 12volt regulator to each pedal as most 9volt pedals will run on 12 with no problem. 

[tasos]

i wanna power all my pedals with one power supply...this is why i am thinking about the voltage multiplier with a max1044!with a 12v regulator probably!

Just be sure to check the current requirements of the MAX chip. I believe it is down in the low mA when powered by 9V. It may run 1..... possibly 2 pedals but, I doubt it will provide enough current for more than that.

Good Luck 

i am thinking of putting the max1044 inside the box so it will only run one pedal!the tube drive!

guys i have read that this pedal at 9v doesn't sound really great...
what do you think?does it really worth it using a charge pump etc etc?

[zambo]

if you build this pedal right it sounds good at 9 volts but only with a 12au7 tube. I have never run across cothode stripping in a tube at 9 volts by the way. I am sure it can happen but it hasnt yet and I gigged a triple caster really hard for over a year. 12 volts is nice and the higher you go the better they sound. at about 100 volts and up they sound really good but there are many other designs that sound better. I run one at 9 volts and another at 45 as they sound great both ways for different things. its not really a distortion pedal. it just adds a little drive on top of whatever you got going already. I use them to "warm up" solid state amps and they do it well. They also fatten up a single coil guitar nicley. For what its worth. Oh yeah and when i run higher voltage i run 9 volts from the dc jack to pin 5 and ground pin 4. 9 is un connected. i run a seperate wire to my voltage multiplier smps or whatever voodoo i am using. Be careful though. and make sure your parts are rated for the higher voltage.  this stuff can kill you  Cheers, Greg