Sansamp gt2 mod

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Post by yahoo! »

are there any mode on sansamp gt2? thanks in advance!

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Post by Dirk_Hendrik »

A mod isn't a standard "entity". Mods are developen with a certain change in tonal character in mind. Therefore the question is what exactly do you want to change in the sound?
Sorry. Plain out of planes.

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Post by yahoo! »

Dirk_Hendrik wrote:A mod isn't a standard "entity". Mods are developen with a certain change in tonal character in mind. Therefore the question is what exactly do you want to change in the sound?
i want some mids?

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Post by quaternotetriplet »

yeah i also want some mids. . some kind of a switch. which part will i change?

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Post by quaternotetriplet »

bumping this thread.

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Post by 5thumbs »

quaternotetriplet wrote:bumping this thread.
Bump it with a link to a Sansamp GT2 schematic and you'll get a whole lot more help. :)
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by 5thumbs »

It'd also be REALLY helpful if you could include information about which amp model in the SansAmp GT2 in which you're looking to boost the mids. (California/British/Tweed) I'm sure each of those "amps" has its own tone stack associated with it, so you'll have to change bits in each of the desired tone stacks to get the mids changes you're after.
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by quaternotetriplet »

i ve got to redraw the schem.. there's a scheme on tonepad..

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Post by 5thumbs »

OK, Tonepad GT2 schem is a good step. (Click here for the schem, folks.)

We still need to know which amp model with which you want to increase/decrease the mids. Which one? California/British/Tweed or a combination thereof?
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by Hides-His-Eyes »

If you only want an EQ change, would a seperate pedal not be a better solution?

I can't imagine it's particularly nice to work in the GT2.
Testing, testing, won too fwee

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Post by 5thumbs »

Hides-His-Eyes wrote:If you only want an EQ change, would a seperate pedal not be a better solution?

I can't imagine it's particularly nice to work in the GT2.
Mr. H.H. Eyes has a good point. While I usually loathe the eye and finger strain involved working with tightly-populated SMD boards, I can do it if I have to. But y'all might not have the soldering dexterity/experience necessary to work on a tight SMD board.

Here's what the SansAmp GT-2 board looks like:
Image

:shock: Look at the size of the switches and LED compared to caps and resistors.[/color][/b][/i] :shock:

So even if we come up with the mods, you'll have to do the hard part of modding it. If you think you can do it (and if you haven't before, you probably can't without some practice on a sacrificial SMD boards), then game on...let's figure this out. If you think it's beyond your skills, I'd just put an EQ after the SansAmp output and bump up the mids there. (Personally, I'd do the latter first anyway, just so you can get an idea of what frequencies you want to bump up.)

Which brings me to my next "good" idea on this topic...if you can figure out the frequencies you want to bump up, it would be easy to make a gyrator on a daughter board that would bump up those frequencies. Once built, you'd just mount this board somewhere inside the case, then desolder the Tip lug of the PCB-mounted output jack and bend it up, clear of the PCB, but be careful to not break it off. Run a wire from the main PCB pad that formerly went to the Tip of the output jack and run that into the input of your gyrator board. Then, run a wire between the output of your gyrator board and solder it to the now-liberated Tip lug on the PCB-mounted output jack.

If you can figure out what frequencies you want to bump up (and how much...the +/- markings next to the sliders on a graphic EQ will give you the decibels of boost/cut on a given frequency), it shouldn't be overly difficult to make a gyrator board to boost that set of frequencies the desired amount of decibels. If you can do the former, then I'll help with the latter. (I've been working with gyrators in other projects recently, so it might be fortuitous timing for you, as it's fresh in my head and somewhat board-proven at this point.)

But in the end, you've got to be honest with yourself regarding your skills and commitment to completing these mods. If you think you can pull it off your end of things, I bet we can come up with *something* that will get you some more mids out of your GT2. :)

EDIT:
Two good starting resources on gyrators:

1) Simple, Easy Parametric and Graphic EQ's, Plus Peaks and Notches by R.G. Keen. My first read on the topic of gyrators and their use in EQing circuits.

2) Bandpass EQ Calculator by Jack Orman of Muzique.com. Use this to calculate the components required to make your gyrator circuit boost the desired frequencies.
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by quaternotetriplet »

Hides-His-Eyes wrote:If you only want an EQ change, would a seperate pedal not be a better solution?

I can't imagine it's particularly nice to work in the GT2.
i would like to get rid of the tap dancing thing when i play guitar. :D

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Post by quaternotetriplet »

5thumbs wrote:
Hides-His-Eyes wrote:If you only want an EQ change, would a seperate pedal not be a better solution?

I can't imagine it's particularly nice to work in the GT2.
Mr. H.H. Eyes has a good point. While I usually loathe the eye and finger strain involved working with tightly-populated SMD boards, I can do it if I have to. But y'all might not have the soldering dexterity/experience necessary to work on a tight SMD board.

Here's what the SansAmp GT-2 board looks like:
Image

:shock: Look at the size of the switches and LED compared to caps and resistors.[/color][/b][/i] :shock:

So even if we come up with the mods, you'll have to do the hard part of modding it. If you think you can do it (and if you haven't before, you probably can't without some practice on a sacrificial SMD boards), then game on...let's figure this out. If you think it's beyond your skills, I'd just put an EQ after the SansAmp output and bump up the mids there. (Personally, I'd do the latter first anyway, just so you can get an idea of what frequencies you want to bump up.)

Which brings me to my next "good" idea on this topic...if you can figure out the frequencies you want to bump up, it would be easy to make a gyrator on a daughter board that would bump up those frequencies. Once built, you'd just mount this board somewhere inside the case, then desolder the Tip lug of the PCB-mounted output jack and bend it up, clear of the PCB, but be careful to not break it off. Run a wire from the main PCB pad that formerly went to the Tip of the output jack and run that into the input of your gyrator board. Then, run a wire between the output of your gyrator board and solder it to the now-liberated Tip lug on the PCB-mounted output jack.

If you can figure out what frequencies you want to bump up (and how much...the +/- markings next to the sliders on a graphic EQ will give you the decibels of boost/cut on a given frequency), it shouldn't be overly difficult to make a gyrator board to boost that set of frequencies the desired amount of decibels. If you can do the former, then I'll help with the latter. (I've been working with gyrators in other projects recently, so it might be fortuitous timing for you, as it's fresh in my head and somewhat board-proven at this point.)

But in the end, you've got to be honest with yourself regarding your skills and commitment to completing these mods. If you think you can pull it off your end of things, I bet we can come up with *something* that will get you some more mids out of your GT2. :)

EDIT:
Two good starting resources on gyrators:

1) Simple, Easy Parametric and Graphic EQ's, Plus Peaks and Notches by R.G. Keen. My first read on the topic of gyrators and their use in EQing circuits.

2) Bandpass EQ Calculator by Jack Orman of Muzique.com. Use this to calculate the components required to make your gyrator circuit boost the desired frequencies.
thanks got an idea..

edit:

how about a mid boost knob?

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Post by 5thumbs »

quaternotetriplet wrote: thanks got an idea..

edit:

how about a mid boost knob?
Great idea, but all of the stuff I mentioned before still applies. You need to know the following before you can do a "mid boost knob" mod:

1) What center frequency do you want to boost? For example, 1Khz is a commonly-boosted lower-mid frequency, giving more "fatness"...3.5-4Khz is a range of upper-mid frequencies that can sound very harsh if overdone...but boosted properly, it will give you more clarity and bite...etc...etc. I'd recommend spending time with a big graphic EQ to try and figure out the center frequencies and and the amount of dB boost/cut on each. If you don't know this info, you will have no idea what to tweak in the pedal tonestack -or- what to boost/cut in your add-on gyrator circuits.

2) If you're talking about a true "mid boost", you're looking at a daughterboard arrangement like I described in the earlier post. This means that the boost will apply to all amp models in the pedal. For starters, you'll probably have one op amp (configured as inverting summing amplifier) and at least two gyrators (one boosting 1Khz and another boosting 3-4Khz, but with less gain on the 3-4Khz gyrator) and a 12mm B100K pot as a level control for the boost. While we can get some moderately high Q values out of gyrators, we'd probably keep these as 2/3-octave slope inductors, as that is pretty typical of most low-end EQs and many of the gyrators I've seen in other pedals. (If you want a taller, but narrower, peak in your boosted frequency, we can adjust the values of R1 and R2 in the individual gyrators to increase the Q of the inductor.)

So a "mid boost knob" sounds fine, but there is still some homework that you must do. I can't do it for you, as these decisions pertain to the sound that you want. You have to have an idea of what you want before I can help design a booster that will meet those design goals.
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by 5thumbs »

Yet another idea on how to boost the mids would be to put in a band-pass bypass (pair of HP/LP R-C filters) whose input taps into the main circuit path just after the input buffering/impedance-setting components. The output of this band-pass filter would feed back into the circuit before the output buffering/impedance-setting components.

I'm not sure this would be much easier in terms of component count than the gyrator idea, as you'd have to have either transistor or IC buffers wrapping the filters to increase the Q value of the filter, reducing the slope of the attenuation curve and increasing the amount of boost. (The buffers would also help prevent "tone sucking" when the band-pass bypass is turned down.)

Not necessarily a "better" way to do this task, but it's yet another method to skin this cat, so to speak.
Modding a DS-1? Please read 'Build Your Own DS-1 Distortion'.

"Other than a good first-in-line buffer/booster, using other FX to improve bad clean tone is like gift-wrapping garbage."

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Post by quaternotetriplet »

ive seen paul'c tim pedal... it has a loop.

how can i incorporate loop on the gt2?

my plan is to put a equalizer pedal on the loop.. hence will reduce tap dancing,

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Post by quaternotetriplet »

any one knows how to wire the fx loop?

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Post by mozwell »

Found this mid band eq for GT2 on my travels.
GT2 midband eq add on by STM
GT2 midband eq add on by STM
Modified GT2 equalizer with midband.png (59.16 KiB) Viewed 8374 times
Hope this helps.

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Post by ebuprofen »

Hey, guys!

I want to mod an original GT2 a bit
1) Make Tweed sound less bassier
2) Make Tweed sound more quietly that California

I'm using only these two mods and want to make California sound more powerful, that Tweed, but Tweed has a lot of bass

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Post by mecmast »

mozwell wrote:Found this mid band eq for GT2 on my travels.
Modified GT2 equalizer with midband.png
Hope this helps.
Hi, i am new to schematics. May be this is stupid question but is there an IC or Opamp used in this schem? I couldnt figure out the triangles shown with "X4" and "X5". What are they?

Thank you.

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