GT-2 stompbox

[Marc100]

I was wondering what kind of a box(a 'BB' type box seems a bit tight) should be used to build and hold the Sans Amp GT 2 stompbox. Also can anyone suggest the best selector switch to use.

Thanks for your help!

[brett]

Hi.  I've built 2 of these.  I found it a fairly tight fit in what I think you  call a "1590B" :?:  I't about 90(wide) x 110(high) x 60(deep).  Given that you've got 3 3-way switches and 4 pots, I would be surprised if you can fit it in anything much smaller.

Re: switches.  For my internal-to-an-amp version I used large rotary switchs, but in the box I used 3 small (25mm x 10mm) linear switches.  Unfortunately that meant cutting out 3 long "slots" in the top of the box by means of multiple drill holes and an hour of filing.  The end result would have been kinda neat if I'd taken a little more care.

Actually, since I don't use it, send me your address and I'll send it to you.  (Now that I think about it, I'm not completely sure that I hooked up the switches properly, so it might be acting a bit screwy.  But hey, you're getting it for the right price!)

cheers

[brett]

Here's the switch that I used;
www.dse.com.au/cgi-bin/dse.storefront/3f86343601155934273fc0a87f9c0683/Product/View/P7614

[Marc100]

Thanks for your feedback! I have decieded that bigger is going to be the best way to go. There is no reason to be cheap in size. Thanks also for your offer to send me your old stompbox, but based on the fact, that I live in the USA, the postal costs alone would be a reason why not to ship it to me!

Marc

[Gil]

http://photos.walla.co.il/gilwein

Click on DIY to get an idea of what I used for the GT2.

The selectors are three rotary 4P3T as far as I remember.

[Manolo Dudes]

I worked very hard to end up with a nice enclosure for my GT-2 project. Look in:

http://www.pisotones.com/GT2/GT2.htm

In spanish, sorry  :roll:  but with lots of photos and a detailed schematic showing the positioning of components inside the box.

[jimmy]

hey brett,

you can send me your GT2 :wink:

cheers
Jim

[ErikMiller]

That is one nice-looking SansAmp clone.

Bueno!

[MarkB]

I think Manolo's clone is nicer than the original... those rotary switches with the tri-color LED's... awesome!
"-)

[Manolo Dudes]

Thanks. I'm responsible of the guts, electronics and final assembly and cabling... the design, painting and silkscreening was made by my pal Ruben Hernandez who is indeed an artist  

Nice, huh?

[Vasiliok]

Guys, you know the schematics on tonepad is not correct?
It has some bugs!

And the main thing - original GT2 uses another ICs!

It uses one TLC2264C!
But you can use 2x TLC2262C.

A friend of mine from Russia has got original GT2. He made a copy using schematics from tonepad and compared these pedals.

Original sounds a little bit better!

So use this corrected schematics:




Sure you can use TL072 for IC2 and IC3, but use TL062 for IC4.

[Arno van der Heijden]

Hi Vasiliok,

Can you give us some more details? I did find some info about this on different Russian sites, but I don't speak Russian.  :roll:
Is this an earlier version? What is SA1.1? Is that the bypass switch? How does DarkAngel know the part # of the IC's since their markings are generally removed?
Does DarkAngel speak English and how can he be reached?

[Vasiliok]

Hi Arno!

I can't provide you with details    but DarkAngel can... I think...

Yes! SA1.1 is a bypass stomp switch.

I don't know how DarkAngel knew part # of ICs man  :?
But I saw Tech21 Double Drive schematics! It uses TLC2262C ICs too...
It's fet semiconductors based IC. That's why it produces good sound when being overdriven...

I dunno if DarkAngel speaks English but I can contact him via email!
Email me man and I'll forward your email to DarkAngel.

Respect,
Igor.

[Arno van der Heijden]

Would the use of the TL062 opamp instead of the TL072 make any difference for the sound? I guess not, since (I think) IC4a and b are used in their lineair region(?). They don't distort, but are used for toneshaping (tone controls & speaker sim) purposes.

I guess the influence of IC2 and 3 is a lot bigger, and since TLC2262 opamps are rail-to-rail devices, they might sound somewhat different. Opinions?

[Manolo Dudes]

Anyone with the original box can confirm that pins 5 & 2 are interconnected in IC1 as in DarkAngel's schematic and not 5 & 3 as in Tonepad's?

Regarding the photo and the schematic in Axiomdrift, I think IC1 should be the one in the center row, just at the right of the switches.

[12afael]

mmmm... what about the output buffer?

I still have problems with my second gt2 maybe could be some of these mods.

RafAel

[Manolo Dudes]

BTT

Anyone with the original box can confirm that pins 5 & 2 are interconnected in IC1 as in DarkAngel's schematic and not 5 & 3 as in Tonepad's?

Regarding the photo and the schematic in Axiomdrift, I think IC1 should be the one in the center row, just at the right of the switches.

Anyone?. I think there's something wrong in the schematic. It doesn't sound as good as it should.

[Manolo Dudes]

Nope!... I've got a friend's original GT2 and dismantled it (lotsa work!)

Both non-inverting inputs in IC1 are interconnected as originally proposed by J. Luja and then drawn by Francisco Peña. That is, pins 3 and 5 are linked.

But, what has amazed me in the original PCB is that what is supposed to be a quad op-amp (IC2 and IC3) in Tonepad's layout is a 14 pin SMT chip labeled as HEF4013BT, that is, a dual D-type flip-flop (datasheet). I don't know the use for such a chip there. Anyone?.

IC4 is a SMT 8-pin chip with the reference sanded out and the components in the upper-right side of the PCB are hidden with a glued in black plastic cover :shock:

BTW: in the PCB I revisioned, version "GT2B_2" just like the one you can see in Luja's web, r29 is 10K, not 22K as stated in red in the older version (GT-2_12) shown in Vasiliok's Lithuanian page. Too bad i have no means to measure capacitors already put in a PCB  

[Vasiliok]

Oops! (-:

Manolo Dudes,
one remark! It's not Dark Angel's web page! It's mine! (-:
Dark Angel is a friend of mine (-:

[Joep]

The HEF4013BT is for the bypass-switching, it's not in the effect circuit itself.