GTFO - Full tube high-gain pedal (2x 12AX7)

[Hilli]

Hi.My english is not the best, but I will try it. I think I know what your problem is. You can see in the PCB!, not in the layout!!!, there is a big ground-plane that connects everything. The layout is for guidance only when you plant the parts.

And yes, I'm using Silva Mica's.

Greets

[fair.child]

Hey Hili, looks like awsome build,

I wanted to built this pedal too. Seems yours mod from the previous schematic is using Baxandall Theory. It is great idea to put into this pedal.
So, I want to asked about the R16 ,R17, and the rest (Pots,etc) question about your pedal. I still can't find where does it go. Could you please tell me ? I'm kind a confused here, and hope somebody will help me to built this pedal. I just need to know where is the ground pad of this Bad ass pedal.

If you don't mind, please share me about the grounding pad. I'm trying to understand the schematic and PCB, but I still can't found it.

And also, did you put a Silver Mica caps on C10 and C14 ?  

Thank you

You can use anywhere on the ground plain for ground...  I would guess that silver mica caps would work fine for c10 and c14..

thank you for your fast reply Jim and Hili. I'm glad to know it

(Yeay my english too Hili, sorry about my poor english, kind a big confusion here, hope you'll understand)

Just to make sure I'm doing right and one the track.

here's what I think about this project

http://dl.dropbox.com/u/3891278/GTFO.png

About the Silver Mica's, Can I use a capacitor that has a lower voltage value of 2kV for silver mica? I think the capacitor has a less voltage han 2 kV, Does it still safe to use ?
I will think twice and read the BOM again for the HV caps.

Anyway, Thanks for your help Jim and Hili, Both of you're the person who help me to solved my confusion and insomnia about this silly question.... arggghhh I'm very pleased with your answer

Cheers

[Hilli]

And don't forget the jumper under IC1. First I had mounted the IC, than I saw the jumper...  

[J0K3RX]

Also fair.child, you asked about R16 and R17... I believe they have been omitted/left out of Hilli's modification. Please correct me if I am wrong Hilli and Great looking build by the way!!! I am wanting to do what you did with the full tone stack! I may try it tonight.. Thanks!

EDIT: Hilli - Any gut shots of your tone stack mod? Also it looks like you mounted the circuit board with screws from looking at the top of your pedal...? Would like to see where you located the screws/holes in the circuit board so that they did not get in the way of anything? I think I can guess but I like pretty pictures lol   Kinda tight inside my build...


~ Jim

[Hilli]

You are right Jim. If you build with complete tone stack you do not need R16-R17 and the other stuff after C6. Maybe, if the signal is too loud, you can insert a 47K resistor (try out) from output to ground to reduce the signal.

Edit: I will send any guts tomorrow, first I must finish "remaining work details"  
Edit2: The enclosure is not a Hammond BB, it is a JJ and a little bigger.

~ Bernd

[J0K3RX]

You are right Jim. If you build with complete tone stack you do not need R16-R17 and the other stuff after C6. Maybe, if the signal is too loud, you can insert a 47K resistor (try out) from output to ground to reduce the signal.

Edit: I will send any guts tomorrow, first I must finish "remaining work details"  
Edit2: The enclosure is not a Hammond BB, it is a JJ and a little bigger.

~ Bernd

Very cool Bernd!!! ah ha.. I thought your box looked a little bigger than mine!  I will be looking forward to it!   Great mod as I was thinking of something like this myself... The tone controls on this did very minimal, maybe adds or takes away a little presence... Not to take away from the original pedal design at all because it still sounds awesome!!! I am guessing that the added bass/mid/treble will sound great and allow for better tone shaping!!

[fair.child]

And don't forget the jumper under IC1. First I had mounted the IC, than I saw the jumper...  

Hey Jim and Hili, I have a few question again, hope you will answer me
I saw a pad between the fifth number from the tubes ? It is connected. What is the function of this pad ?
I give a red mark on it. I've realized it from the Jim previous post that it has a wire on it, so where it should go ?

http://dl.dropbox.com/u/3891278/GTFO.jpg

and can Silver Mica accommodate 2kV (HV) on this board ? Generally, this is a silly basic question, but I'm curious to know.

About the mods,
Please check this http://dl.dropbox.com/u/3891278/GTFO%20Mods.png, I'm quite doubt about my pots orientation, am I doing right ?
Again, just to make sure the mods are working

Cheers

[J0K3RX]

And don't forget the jumper under IC1. First I had mounted the IC, than I saw the jumper...  

Hey Jim and Hili, I have a few question again, hope you will answer me
I saw a pad between the fifth number from the tubes ? It is connected. What is the function of this pad ?
I give a red mark on it. I've realized it from the Jim previous post that it has a wire on it, so where it should go ?

http://dl.dropbox.com/u/3891278/GTFO.jpg

and can Silver Mica accommodate 2kV (HV) on this board ? Generally, this is a silly basic question, but I'm curious to know.

About the mods,
Please check this http://dl.dropbox.com/u/3891278/GTFO%20Mods.png, I'm quite doubt about my pots orientation, am I doing right ?
Again, just to make sure the mods are working

Cheers

That pad between the tubes that you have marked in red is for the 12v heater... I ran a wire directly from the 12v DC input to this pad.
The silver mica should be rated at 2kv, if not you may have problems... What are yours rated at?

[fair.child]

That pad between the tubes that you have marked in red is for the 12v heater... I ran a wire directly from the 12v DC input to this pad.
The silver mica should be rated at 2kv, if not you may have problems... What are yours rated at?

ahh, I see that, okay, thank you for your confirm Jim
so, the marked 5th pad is for the 12V DC heater

about silver mica, I believe mine should be rated under 2kV in my SM mark. It is around 500V. Is it still possible to use it ?

Cheers

[PRR]

> Can I use a capacitor that has a lower voltage value of 2kV for silver mica?

Use 400V or 500V.

Just like real tube guitar amplifers.

Silver Mica was sometimes used in radio transmitters or TV sets at high voltage, so 2,000V Silver Mica used to be available.

ALL high-voltage work is out of style today, so some new SM is rated 50V.

This amp runs 100V-400V depending on your power supply. 400V-500V rated caps will be fine.

[Hilli]

And don't forget. Working with high voltage is dangerous and can be deadly. Be careful.

[J0K3RX]

And don't forget. Working with high voltage is dangerous and can be deadly. Be careful.

No doubt! \\\SHAZAM///

Bernd, I was hoping to see some gut shots of you tone stack mod? If not that's ok...  

My GTFO gets quite warm/hot after a while of playing... I was thinking to install a small fan on the front to expel the heat from the inside of the pedal..? Thoughts?

[PRR]

> Thoughts?

Tube stuff is supposed to run hot. Enjoy.

[amptramp]

And don't forget. Working with high voltage is dangerous and can be deadly. Be careful.

Beware the Ides of March.  Which is today.

[Hilli]

Bernd, I was hoping to see some gut shots of you tone stack mod?

Sorry, I didn't had the time to make photos. I will send they in the next few days (tomorrow).

[J0K3RX]

> Thoughts?

Tube stuff is supposed to run hot. Enjoy.

Yeah, I know... Not really worried about the tubes themselves... I am more worried about the components trapped inside the box... Glad I got all 105c capacitors!

[Hilli]

Jim, did you make pictures?

[J0K3RX]

Jim, did you make pictures?

[Hilli]

Wow, Cool. How have you mounted the PCB? There are no holes....

[J0K3RX]

Ok, here is a "REAL SHITTY" sound clip of it running direct with very slight delay and a mesa boogie cab impulse .... I am tired and just chuggin a little to let you hear the tone I am getting... Not trying to impress lol

I have an amp and I have ran it through it also and to me that is the way to go!! It really kix ass going into your amp in my opinion but my brother has my SM57 so direct it is for now...

Please don't laugh

http://dl.dropbox.com/u/11178619/GTFO-1%20TEST1.mp3