tubeworks tube driver questions

[REGNAD]

hey folks, i have a tubeworks tube driver with three knobs. is there a way i could use a double shaft pot and have a bass and treble adjustment? and is this the correct schematic for this particular pedal? --->http://www.muzique.com/schem/tubedrvr.gif  also, on the schematic is recomends powering the circuit with 12  volts instead of 9. wouldnt that cause damage to the unit? thanks!!

[sean k]

Man, just about anything is possible with enough committment, money and willpower.. and the right kind of knowledge, skills and tool base.

But thats not what you're asking is it? The suggestions are good ones, at the bottom of the page and if you get some tube specs for the 12AX7 and the pinout for the 4558 then follow through the schematic and the box you have you may find that they are indeed the same... or they aren't. I have no idea but can surmise that the likelyhood is in your favour given the info you have given. If you can do this to your own satisfaction the chances are you might also be able to do the next part of your question. Baxandall is your clue.

Bugger the 12V and go for 12.6V   

The tricky part is finding the dual shaft with the right tapers and resistance that allow cool knobs. Hmm! Good Luck and may the force be with you... Grasshopper 

[REGNAD]

....................... what??

[sean k]

Sorry about that, I was being obtuse and hoping you'd realise that all your answers are out there if you just do some searching then get to know the box you have. The 12AX7 is designed to be run on 12.6V with the filaments in series or 6.3 volts in parallel. The schematic shows the filaments in series and on 9V the filament won't be heated to it's potential so the the electrons running free and available for amping won't be as great as if the filaments were powered by 12V.

A normal tone stack cuts frequencies whereas a baxandal, well an active baxadall, tone stack will both cut and boost frequencies, usually treble and bass, and because it's active you should be able to use the twin shaft pots they use in car audio type stuff as they'd be in the region you need. But you'd need another 4558 to buffer the signal in and create the active tone circuit. I say this because it might be quite hard to find a dual shaft set of pots that'll suit the resistances used in high impedance tone stacks.

Upping the input to 12V ain't gonna hurt anything as long as your power supply caps are rated above 12V and are most probably 16V anyways so you'll be fine. You could up the resistor to the LED to 2.7k but the 2.2k won't cause it to blow so even that doesn't matter.

[REGNAD]

thanks sean, sorry for the confusion. lets talk about the voltage. what could i expect from upping the voltage as far as tone? i did go to electronics school but sometimes i dont follow when it comes to the stomp boxes. seems like it would ideal to increase the voltage to the pedal, but ive been trying to get my hands on one of these tube screamers for a looong time... i would vomit if i damaged it. i can read schematics, but i may have several questions to make sure im on the same page as you guys! other than a power supply capable of the 12.6, do i need to make any mods to the pedal to accept the higher voltage?

[petemoore]

 lets talk about the voltage. what could i expect from upping the voltage as far as tone?
  The plate voltage increase should very slightly increase headroom.
  Also will increase whatever IC portions output is feeding the tube [if any?], requiring more headroom in the tube, 'go figure..hard to say' pedal will should be a touch louder.
I did go to electronics school but sometimes i dont follow when it comes to the stomp boxes. seems like it would ideal to increase the voltage to the pedal, but ive been trying to get my hands on one of these tube screamers for a looong time... i would vomit if i damaged it.
  You mean Tubedriver [?].
  I can read schematics, but i may have several questions to make sure im on the same page as you guys! other than a power supply capable of the 12.6, do i need to make any mods to the pedal to accept the higher voltage?
  Don't apply more voltage than a component is rated for.
  Measure the wall wart output voltage, it is probably a good margin higher than what it s markings would have you believe, designed to be at least the marked voltage when under 'heavy' loading.
  Adding 10% to that [for AC voltage fluctiations and good luck], is generally considered safe.
  I would decide what the TD doesn't do, try to understande if a small voltage increase is going to make any difference there.
  After so many words I can't see the bottom of the page.
  Consider the max voltage of a 12ax7, decide if LV tubes are what you want to play around with. They do what they do...

[FlyingZ]

I switched the 12AX7 with a 12AU7 and now it's much better.
I think you are correct that the tone stack could use a little adjustment. The mid control is too bright.

Post back what you come up with.

[REGNAD]

i dont have the stock power adaptor for this tube driver. so im not sure what the stock xformer's rating is. ill check the web.  it does seem that the tube drive knob is either bad or is it normal for the tube breakup to not change much if at all after around 12 oclock?

[FlyingZ]

I thought it was something else, never mind my posts.