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

[Granny Gremlin]

Final version of the docs is still being worked on, I'm told.

[gtudoran]

Had a lot on my table lately but the build document is going to be ready soon (i do hope this week).
The new version will be divided  in 2 blocks:
- SMPS module
- Main board (tubes board)
and it's going to use 1590C type enclosure (all elements are inside). The PCBs are double sided (with vias).

Regards,
DeX

[Hades_Snake]

Hi,

Does your IRF740 heat up a lot? Cause mine does...

Do you think i can substitute the IRF740 with an IRF840? Looks like it's on the edge at 400V (it's data sheet limit). I've burnt a couple cause of that...

[Granny Gremlin]

Hey gtudoran - did that build doc ever materialize?  I'm not on facebook so you said you'd email it to me when you were done.

[J0K3RX]

Hi,

Does your IRF740 heat up a lot? Cause mine does...

Do you think i can substitute the IRF740 with an IRF840? Looks like it's on the edge at 400V (it's data sheet limit). I've burnt a couple cause of that...

Yes, you can use an 840. I use IRF840's on all of them that I have built except for the first one a couple years ago. Didn't go much past 320v on that so it was probably alright.. Use the 840 but you should still use a heat sink in my opinion, even with the 840 it still gets smokin hot. I use a pretty large inductor also, I got lucky and found a bunch of 5 amp 100uH coils probably about the diameter of a dime and they run substantially cooler than the ones that I was using rated at 2 amps..

[GzVirus]

^ nice demo....sounds cool detuned too.  \m/    \m/

out of curiosity what is the tone control on that?....

edit: scrap that i see the schemo!..

Thank you, you have all the details in the PDF document.

Best regards,
Gabriel Tudoran
Analog Sound

dude，the page is 404，can u fix that？

[DarthKaker]

Ou man! Great work is it possible to get these docks or eagle project?

[gtudoran]

Yes you can use IRF840 but keep in mind that RdsON is higher then 740 and that will cause a lot of heat. No my 740 is not running hot (50 to 60 deg max inside the enclosure).
Of course as i said the PCB of the SMPS is critical for both efficiency and stability so no i would not recommend the use of 840 without a heat-sink.

@Granny Gremlin no i didn't finished the build document but i will write you an email (and detailed pictures of the build) so you can finish the project (if there is a need for that) or we can have a skype call.

Regarding the docs from the original GTFO project, those are no longer available, literally no longer available because of a HDD crash couple of years ago.
Also keep in mind that the GTFO project was released under the GPL licence so no commercial activity is allowed.

At least but not at last, the kit project for this pedal was suspended because of the lack of interested. The pedal will be available in the form of ready to use pedal with wall-wart included in the price, but, i'm not going to support this project anymore for the public use

The only info that is available and will remain available will be the one that is posted on this topic until now. I'm really sorry that i can't offer support any more for this project.

Regards,
DeX

[Uriziel]

Hey. I may have a strange question. I plan on building that pedal in the future with a small "twist" but for that I would like to know what kind of voltages are present across the potentiometers. Can anyone help me with that? Is it possible to hook up an active device that has a max input voltage at 15V, instead of the potentiometers.

[efe]

Great project and i want to start building ASAP but can't see dropbox files. Are they deleted ?

[GibsonGM]

Hi efe, welcome to the forum.   I built one recently and have some files related to the power supply, basic schematic, and Joker's mods (which I recommend!).

Here is the basic info you need to get going: http://i.imgur.com/AtdElol.jpg

This one has "Joker's Mods", some changes that Joker made that I found good improvements: http://i.imgur.com/ymNdVGh.jpg

Let us know how it goes for you!

[mikestorm]

Hi to all

I'm interested in building the gtfo, the only problem is that i havent time to do the two pcb's.

Can someone, in the usa, make me the pcb's of the working version of the pedal?

Please let me know
Mikestorm

[gtudoran]

Try and see if you find some PCBs on ebay or olx.pl - it was copied as hell without even credits given

[mikestorm]

Hi gtudoran

Thanks for the reply, no pcb on sale on ebay and olx.pl

I dont know if you remember, we send each oder a couple of mails years ago on the gtfo, the only problem, i live in DR, it would be perfect if i can find the pcb's in the states, so with a private courrir, i will bring it to me .

however i'm opened to alternative solutions

a question: As this pedal got a couple of years, does anyone got problems of malfunctioning on the power supply side(inductor/IC/Mosfet)?

Thanks for the reply
Michele

[gtudoran]

Hey Michele,

As i said i don't offer any type of support for this project really sorry about that but i was quite pissed on some things and ... preferred to go commercial with it.
Now is available via my site as a ready to use product, with some big improvements.
From my side there is no kit version or PCB only and will never be - the GTFO as an open source pedal is no longer in plan.
If you can find the old files i can answer to specific questions but i will not be able to offer you any kind of support.
You can find me on FaceBook to the following address: https://www.facebook.com/dextersworkshop.ro

regards,
DeX

[mikestorm]

Thanks gtudoran

I respect your point, no problem, i keep on searching...

[BetterOffShred]

I hadn't really ever looked at power supplies for Tube preamp pedals.. It's kind of amazing that a NE555 can supply 310V properly coaxed.  I'll definitely have to mess around with this. 
Edit: I guess the IRF740 is really doing the heavy lifting.

[temol]

I'm going to start GTFO build soon but one thing puzzles me.. there is a pcb design available  in this thread (Reply #407). So, this design has a copper fill around whole board. Has anyone experienced any issues because of this? I have two or three layouts in which I had to break a copper fill loop.

T.

[vigilante397]

I have two or three layouts in which I had to break a copper fill loop.

Really? Why? Using a ground plane is fairly common practice, I do it on most of my PCB layouts and never personally had any problem with it.

[temol]

I had oscillation problems in my latest build. Not sure why.. maybe my poor pcb design, maybe circuit itself prone to oscillation. It stopped after "surgery".

T.