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

[gtudoran]

Hey J0K3RX what is this factory can you explain it?! And nice design btw very nice design! Congrats.

Best regards,
Gabriel Tudoran
Analog Sound

If you guys are gonna do this on vero with the tubes not connected to the main board you might consider mounting the tubes so the are parallel to the enclosure. That way you can enclose them inside the box so they are not protruding out of the top of the pedal? I know the tubes look cool sticking outa the top like a blower sitting ontop of the hood of a 69 camero... but even with the roll bars it scares me and I could still damage them easily..

I know these are not vero but just to give you some idea of what I am talking about..

[vigilante397]

Hi vigilante ...

very nice layout you posted ! I am also in the process of populating the parts for this project... do you mind take a pic of your done velro board? does it fit into a 6500 enclosure?

mind to ask how do you intend to sort out the tube sockets? do you intend to mount it on a Velro board as well?

Thanks, I'm also still waiting on my parts for this project. I think mine also cost close to $100 But if it works then it will be worth it I haven't build it yet so I don't really know how big the board will be. When I made the layout I spaced it out more than I needed to just to make it easier to read, so it could potentially be about half the size I made it

I was planning to mount the tube sockets on top like I did on this one: https://www.dropbox.com/s/kbsqrn1kcm3dgfp/twincaster-vigilante.jpg

If you guys are gonna do this on vero with the tubes not connected to the main board you might consider mounting the tubes so the are parallel to the enclosure. That way you can enclose them inside the box so they are not protruding out of the top of the pedal? I know the tubes look cool sticking outa the top like a blower sitting ontop of the hood of a 69 camero... but even with the roll bars it scares me and I could still damage them easily..

I know these are not vero but just to give you some idea of what I am talking about..

I know putting the tubes inside the enclosure would make it a lot more secure, and the blue glow out the sides looks AMAZING on that build, but I've had some nightmare builds where I overcrowded the inside of the box and it was a huge headache to get everything done. One of the main reasons I really want to get into PCB etching is because of how much space and clutter it reduces, not to mention the simplicity and organization. But while I'm using vero and point-to-point on the tube sockets I really think my best option is to put the tubes up top.

When my tube pedals (slightly modded Matsumin Valve Caster and Twincaster) are not plugged in and in use the tubes are removed, put into boxes, and stored in my tubes drawer. I've broken one tube in my life and now I'm super paranoid about it, so I definitely understand where you're coming from.

So anyway, my parts for this should all be here in about two weeks (economy shipping ), so hopefully I'll have time to get going on this even with the new semester starting tomorrow for me

[vigilante397]

Also, before I forget again, there are two components I still haven't ordered because I want to make sure I'm getting the right thing:

- 100uH inductor: I read through the posts again on this thread and I think I know what to get now, so I can order that today

- Pot #5: I understand this is just a trimmer pot, but I don't see anywhere in the parts list what the value should be, and I'm having trouble even finding the things on Tayda.

Help please?

[vigilante397]

Okay, so I found the trimmer pots on Tayda, but I still don't know what value I'm supposed to be getting. Anyone? 

[gtudoran]

vigilante397: anything from 10k to 20k would work very good.

Best regards,
Gabriel Tudoran
Analog Sound

[Uriziel]

vigilante397: anything from 10k to 20k would work very good.

Best regards,
Gabriel Tudoran
Analog Sound

Wasn't it 5k trim with effective range up to 2k... i remember someone in this topic did some measurements with different pot values and got that values over 2k were pretty much unnecessary since everything over that will just cause the voltage to be too low for the full effect to be heard... i used a 2k trimpot myself...

That someone was mr. PRR somewhere on page 4 of this thread

[gtudoran]

What i wanted to say was, that the value is not critical and you can stick anything there (it will not do any harm as it will not do any good )

Best regards,
Gabriel Tudoran
Analog Sound

[JimSoprano]

hi All,

I like this project very much! And I'm going to build it!

a few questions..
1 with the tonestack installed, is there a loss of gain, or a loss in tone?
2 which pots has to be log/audio or lin?

thank you very much?

Grtz Jim

[gtudoran]

@JimSoprano: for the original build volume and gain should be log (A type), tone pot should be linear (B type).


Best regards,
Gabriel Tudoran
Analog Sound

PS: for the tone-stack mod bass pot should be Log and the rest Lin

[JimSoprano]

@JimSoprano: for the original build volume and gain should be log (A type), tone pot should be linear (B type).


Best regards,
Gabriel Tudoran
Analog Sound

PS: for the tone-stack mod bass pot should be Log and the rest Lin

thanks for the info Gabriel. What do you know about the gain and tonal differences between the tone and bmt versions?

[hopkinWFG]

Hi vigilante ...

very nice layout you posted ! I am also in the process of populating the parts for this project... do you mind take a pic of your done velro board? does it fit into a 6500 enclosure?

mind to ask how do you intend to sort out the tube sockets? do you intend to mount it on a Velro board as well?

Thanks, I'm also still waiting on my parts for this project. I think mine also cost close to $100 But if it works then it will be worth it I haven't build it yet so I don't really know how big the board will be. When I made the layout I spaced it out more than I needed to just to make it easier to read, so it could potentially be about half the size I made it

I was planning to mount the tube sockets on top like I did on this one: https://www.dropbox.com/s/kbsqrn1kcm3dgfp/twincaster-vigilante.jpg

If you guys are gonna do this on vero with the tubes not connected to the main board you might consider mounting the tubes so the are parallel to the enclosure. That way you can enclose them inside the box so they are not protruding out of the top of the pedal? I know the tubes look cool sticking outa the top like a blower sitting ontop of the hood of a 69 camero... but even with the roll bars it scares me and I could still damage them easily..

I know these are not vero but just to give you some idea of what I am talking about..

I know putting the tubes inside the enclosure would make it a lot more secure, and the blue glow out the sides looks AMAZING on that build, but I've had some nightmare builds where I overcrowded the inside of the box and it was a huge headache to get everything done. One of the main reasons I really want to get into PCB etching is because of how much space and clutter it reduces, not to mention the simplicity and organization. But while I'm using vero and point-to-point on the tube sockets I really think my best option is to put the tubes up top.

When my tube pedals (slightly modded Matsumin Valve Caster and Twincaster) are not plugged in and in use the tubes are removed, put into boxes, and stored in my tubes drawer. I've broken one tube in my life and now I'm super paranoid about it, so I definitely understand where you're coming from.

So anyway, my parts for this should all be here in about two weeks (economy shipping ), so hopefully I'll have time to get going on this even with the new semester starting tomorrow for me

yup... but thing is I heard doing this project using vero board is not going to withstand the high voltage circuit here... as a kind soul just told me so and it sounds logical.. i'll be wiser on a 1/8" turret board for circuit which relates to HV...

I hope to settle the PSU first as I think its the most problematic with the correct parts at the correct output you want.. as told I may want something tight sounding not too high on gain but also to have slight "hair" on the tone itself.. seems like 350V as per told is great for a full tube sound....

[HugoW]

Hi all,

my first post here. I've been lurking a bit, and now I want to sink my teeth into this project (the hilli variant on page 12, reply 243). I am making my own PCB lay out, which will contain two power sources too. One to make the 310, and a separate to maken 6,3V=, stabilized and humm free, for the glow wires. It will not so much become a stompbox, as a separate pre-amp. All info on it is clear so far, I have just one question left (untill I have another). How many amps should the power source be able to supply? Either including or excluding the glow wires?

Cheers,

Hugo

[gtudoran]

12v @ 1.2A including heaters would be more then enough (is what i use). And why would you go with 6.3V for heaters when you could user 12.6V (12V) for heaters as you already use 12V to power up the pedal?


Best regards,
Gabriel Tudoran
Analog Sound

[lg_2k5]

Hi Gabriel, excelent proyect. I have one question: the power supply must be regulated? say with an LM3117? because of the amperes, A fixed regulator like the 7812 will not go further than 1A I think. Cheers!

[gtudoran]

It's not necessarily to be regulated. I use switch-mode PSU and everything is fine and quiet as a forest in a winter night


Best regards,
Gabriel Tudoran
Analog Sound 

[HugoW]

... And why would you go with 6.3V for heaters when you could user 12.6V (12V) for heaters as you already use 12V to power up the pedal?

Thanks for the details. To answer your question; the plan is to mate is as a pre amp to a firefly-like power amp. So I will have a transformer taking 240V to power the lot. I will not use a 12V power source for the pre-amp and still use a 'regular' power source for the power amp.

Cheers,

Hugo

[vigilante397]

So I finally have all the parts to get this thing together (despite the postman delivering some to the wrong address  ), now all I need is another 3-day weekend to actually get going on my vero layout. Between school, work, and about 4 other builds I'm working on I just haven't gotten around to this one. Has anyone else had a chance to try out my vero layout? Because as far as I know it's REALLY unverified. But I'll let everyone know how it goes when I get around to it

[JimSoprano]

Hi All!

Is there an eagle file available of the pcb?

can't find anyone who can make the pcb with a pdf layout.

thanks in advance.

grtz Jim

[Uriziel]

Hey Uriziel,

Hmm there is smth i would like to say: why  did you use SMD?? There is a reason why i didn't use SMD in the first place (i could do that but... is much easy to use THD components and also the space is bigger so the interference is smaller). I harder to use SMD components in this design. I saw a lot of vias and a lot of traces that goes under components... that i guess generates a lot of interference.

I just an idea and nothing more, but i would recommend to stick with the original THD design ... you could build the SMPS with SMD components but i would stick to THD on audio signal parts. There is also a reason why the smps is placed in that place. Keep in mind that the SMPS that is used is... a very rudimentary one and was chosen for the small parts count and for the size and so ... the equilibrium is very thin.

Best regards,
Gabriel Tudoran
Analog Sound

PS: You can design a proper fly-back smps and that would solve much more of the problems.

PPS: Don't try to find solutions where there is no problem - i'm referring here to the separate heater PSU, i don't believe that ... DC heaters are better then AC ones in therms of musical quality if everything is designed properly.

So I have put that project aside for a while and recently came back to it... I made a redesign of my pcb, first i tried to use the same topolgy as my first board, then i used fairly similar part placement ideas as the original from Analog Sound that is floating around here... i switched to thd components for everything (before i used smd components)... And the result for both cases: still the same, nothing has changed... i get a lot of hum and noise, mainly hum... i tried switching the PSU i use... i tried RC filtering in the psu part of the schematic... that made the noise even worse... i took out all the pots and used jumpers to bypass the gain pot and tonestack... i tried coupling caps in the signal path, decoupling caps in the power section... i tried bypassing various gain stages to try to atleast pinpoint the source of all my worries and even that I am unable to do... no matter what i do the hum is always present... i checked my guitar for faulty wiring and everything was fine... all the other pedals i have are very quiet... i changed the tubes i used and then changed them again and still nothing... no matter what i do the sound doesn't change except when i put an eq after but that is logical... with that i atleast found out that there is some level of hum at pretty much all the frequencies the amp can produce... so mains hum... this one is an elusive bastard it seems... i read about some hum cancelling techniques used with tubes and some texts say that sometimes the hum can be eliminated if you bias the heaters, but that is when they run with ac... with dc i am unsure that technique applies... sound probe doesn't work here since there is some hum even when the effect is "bypassed" (i use the Hilli version)... on one page there was a mention of using a resistor with one end to ground and the other end to touch the leads of various points in the schematic, mainly caps, while the effect was working to see if it would have some effect... would it help if I tried trimpots instead of anode resistors to try to set the bias manually? actually i remembered that the only effect i had on the sound of the hum was when i put something metal near the inductor... i used an aluminum screen and the hum seemed to raise in pitch but other then that i haven't had much progress

does anybody have any suggestions for me...

[fagnermonteiro]

Sorry guys, but I had some problems and could not continue the project. Now going back to try to do this will be my first tube effect.

Hi fagnermonteiro, did You carry on project realization?
I'm really interested in your mods, cause I would put it into a 1590BB case...did You finish it?
Could  You please give to me your eagle  sch and brd files of this project?
Thank You very much!!
Great job!

Hi fagnermonteiro,

would you send us your layout-files? That would be cool. 

Redards, Hilli

Of course I will share the files with you. I'm learning a lot here and I need you to refine the layout I made to make it as best as possible for everyone.

https://www.dropbox.com/s/2mt4ng3erhemytg/GTFO%20Pedal.sch
https://www.dropbox.com/s/b7hrj7cxtiuykpr/GTFO%20Pedal.brd

PS: Sorry for my bad english. I'm studying the language