Sansamp GT2 California hot wired only

[alltrax74]

I was wondering if it's possible to split the GT2 layout to have only the section with the california hot wired setting ?
It's a great sounding distortion and would save sooooo much wiring from the original layout we already have on the blog
Thanks if someone is willing do to it (Alex ? )

[Alex]

I just need to remove some components but it won't get much smaller.
Won't be back home (were the original file is) for a few days.
What about the MIC switch?
Any particular setting?

[alltrax74]

Hi Alex thanks for your answer
I think the off axis is the one to go with, or maybe a toggle switch to add the center setting if it's simple to do.
Even if it won't get really smaller, the wiring should be significantly lighter

[Alex]

I haven't built it but I think I've removed the correct parts.
Better double check the schematic though.
I've left a switch for Center/OffAxis Mic.

[alltrax74]

Thank you very much Alex
To be sure we are on the same page, did you use tonepad's schematic ?

[Alex]

I did.
You can find it here:
http://www.tonepad.com/project.asp?id=22

[alltrax74]

So, after carefully checking, you removed :

-SW1 : 22k x1 (S1a3)
-SW2 : 10k x1 (S2b2)
-SW3 : 2n2 x1 (S3a2)
           22n x4 + 100k x1 +2k2 x1 + 22k x1 (S3a3)
           22k x1 (S3b2,3)

That's 6 resistors and 5 capacitors less, correct ? (Checking the links and cuts is a bit diffucult as you re arranged the ICs)

[Alex]

That's correct.
I've also used 1 TL071 instead of the dual op-amp.

[alltrax74]

I'll build it within the end of the month and I'll let you know
Thanks again for all your time and patience

[alltrax74]

Hi Alex, I built it it was faster than I thought, but no output signal, effect is dead silent plugged on my test box.
I checked all the usuall suspects my board should be ok (even if we never can be 100% sure)

Here are my voltages (wall 9.65v) :
IC1 (TLC272) : 4.07 / 4.1 / 4.37 / 0 / 3.88 / 4.39 / 4.28 / 9.39
IC2 (TLC272) : 4.36 / 4.35 / 4.1 / 0 / 4.02 / 4.27 / 4.25 / 9.39
IC3 (TL071) : 0.15 / 4.6 / 2.29 / 0 / 0.15 / 4.59 / 9.39 / 0
IC4 (TL072) : 4.58 / 4.58 / 4.33 / 0 / 4.33 / 4.34 / 4.34 / 9.39

Any thoughts ?
Thanks

[alltrax74]

Oups, I just realize I forgot to plug the 5088... 
I'll be back this evening

[Alex]

Well done!
I've also found a little mistake:
There is a 10K resistor going from Low 3 to a 100n cap.
It should go to Low 2 instead of Low 3.
I've already fixed the layout.
Let me know how it goes!

[alltrax74]

Great thanks I'll fix that and let you know

[alltrax74]

Hum are you sure Alex ?
Checking the schematic the 10k you are refering to is connected to low 3 it seems

[Alex]

You are right.
I've printed the wrong schematic:
http://www.6v6power.ru/inf/Preamp/Sans%20Amp%20GT-2%20preamp.jpg
Leave it as it was.
I'll change it back.

[alltrax74]

And here it is, working great and sounding great



Very nice sounding heavy distortion, just as I remembered it was with the original unit. I plugged it in front of my AC15HW1, as expected the Off axis setting is the best mic setting.
I also plugged it direct into my PC active speakers and it sounded pretty decent, good surprise.
I'll have to be carefull when boxing it depending on the board position there can be some high pich sqeels

I think it's worth adding to the main GT2 page
Again, thanks Alex for the great job and your time, much appreciated

[Alex]

Cool! I'm glad it works!
I've done the same thing.
I own a Sansamp Classic since the middle 90's and always kept the same setting (Nirvana's In Utero Tour sound)
When I've drawn the layout for the main page I've drawn a second one for me with no switches and just the setting I liked.
If you just need the Off Axis setting you can remove the yellow 4n7 cap and the switch from the  layout.

[alltrax74]

I'll keep the center position it's the one I'll use with my active speakers which sound a bit darker than the amp. I'll probably box it this week-end

And next on my build list is the Classic (which I owned about 10 years ago) but full options this time

[alltrax74]

And here it is boxed. The funny thing is the day after I finished it, I found an original unit for 50€, couldn't resist

[aelling]

Alex wrote

Cool! I'm glad it works!
I've done the same thing.
I own a Sansamp Classic since the middle 90's and always kept the same setting (Nirvana's In Utero Tour sound)
When I've drawn the layout for the main page I've drawn a second one for me with no switches and just the setting I liked.

Alex, do you still have that layout for the sansamp classic with no switches? If that is with the NIRVANA settings (input switch is Normal, DIP is on-on-on-off-off-off-on-on) then I would love it if you could post it.