I was wondering and wandering around on my pc at work... ;D
and I suddenly got struck by the how-the-h*** syndrom regarding the sansamp GT2.
That really IS opamp clipping. There has been some discussion on this, I know, I searched the forum, but with little results.
Is it (the sound) really coming from tone shaping pre and post the opamps? Since it doesn't look all that spectacular.
if you are asking about the tube tone. the schematic are really simple a couple of gain stages , the speaker simulator filter , a baxandall tone stack and a buffer.
I think part of the secret are the reel to reel op amps, they clip on a diferent way . all other parts are standard.
no seem to be spectacular . :icon_wink:
Pre and post filtering
Steben,
QuoteIs it (the sound) really coming from tone shaping pre and post the opamps?
Mostly yes. But op amps don't all sound the same when overdriven. It has to do with slew rate and saturation behavior when pinned to the rail long enough to saturate various stages. It takes a bit to come back out of saturation. And it's not always symmetrical. Multiple amp packages sometimes share bias networks which overdrive can disturb. That's why op amp distortion isn't so simple - and why different manufacturers versions of the same type number can sound different (subtle, but real).
QuoteThat really IS opamp clipping. There has been some discussion on this, I know, I searched the forum, but with little results.
Go here
http://www.diystompboxes.com/smfforum/index.php?topic=16324.0
The genuine article doesn't use '072s like the ROG clone information shows, they use '2262s.
TLC2262 or 2272s sound better to most folks, especially in the clipping stages, but it's subtle.
If you want to try something different, use the TL070 (it's a single, externally-compensated low-noise JFET op amp) and play around with the compensation cap to drop the slew rate and slow saturation on the gain stage (the output stages will still saturate though). They're getting hard to find, but Steve Daniels has some. You can't use them in the ROG PCB, though, because it's made for duals.
ROG GT2 PCB?
Fp
I'll chime in here and say that using the 2262s made a pretty noticeable difference in my Tonepad GT2. Enough where I breathed a sigh of releif and satisfaction when I put them in. Less feedback at high levels, better clean tones, heavier high-gain tones. Everything about the pedal was better!
Quote from: DavidS on December 06, 2005, 09:43:34 PM
I'll chime in here and say that using the 2262s made a pretty noticeable difference in my Tonepad GT2. Enough where I breathed a sigh of releif and satisfaction when I put them in. Less feedback at high levels, better clean tones, heavier high-gain tones. Everything about the pedal was better!
Well I say...
Sorry FP,
Don't know where that ROG brain-fart came from... I meant the TONEPAD GT2 PCB layout. :icon_redface:
Musta been drinkin' too much :icon_rolleyes:
Thanks for correction.
It's a VERY nice layout BTW. :)
Bart, there's no such thing as drinking too much ;D
:)
Can Sansamp Gt-2 be built in stripboard?
Even if it is possible will it need more than 1 stripboard?