Scoped tube screamer?

[freebird1127]

Hey all,

Is a scoped TS supposed to look like a plateau-d hilly countryside or a skewed triangle wave or is it supposed to be more of a jellybeaned sine wave?  Does anyone know?

TIA

[cd]

Are you talking about the shape of the waveform you see on an oscilloscope?  That depends on the frequency of the input, where you set the tone control, etc.

[freebird1127]

Yes that's what I'm talking about, the waveshape on output.  I know it depends on what you have the settings at, but I'm just trying to find out as much as I can. What would it be for 1kHz Sine in and 6 6 6 on the controls?   What would it be for 10kHz?  etc...

You guys think that If I'm using +/- 15V rails that I have to adjust some components for gain in the clipping stage?  IE so that the gain set by impedance at a certain frequency hits or does not hit the rail limits of the op-amp?  Anyone ever done this before?

[cd]

OK I see what you're saying - basically, what does increasing the supply voltage do to the sound.  FWIW, here's a simulation of a 1Khz, 55mV sine wave into a TS-808 circuit, drive cranked, volume cranked, tone at half.  Top is @ 30V supply voltage, bottom is 9V supply voltage:



The signal is mostly being clamped by the clipping diodes.

[freebird1127]

Great!  And that's pretty much what my signal looks like comin out, maybe just a little more skewed.  Thanks CD!

EDIT:  CD, what's the volts per division on the y axis of that scope for that measurement?  I just wanna know what the output Vp-p is for the signal.

[cd]

Not a problem.  I think I had the graph set at 100mV/division... which doesn't make sense (would make the p/p signal around 300mV).  Hm, I'm double check tomorrow.

[cb]

Hey cd, nice simulation. What software are you using? Also, where did you get the TS808 simulation - did you do it yourself? Thanks.

[cd]

Forgot to update this post.  I forgot to save the graph but I'm pretty sure it was 100mV/div.  I use Multisim7 (www.electronicsworkbench.com).  It allows you to build a circuit very quickly, schematic style, then slap a virtual oscilloscope on the end to check the output.  It's not perfect (depending on what opamp model you use the output can be wrong) but it gives you a general idea of what the output should be.

[lightningfingers]

One of you guys needs to change your name. It's confusing my short-sighted little brain  :wink:

[petemoore]

Nifty!!!

[brett]

Hi.  For those of us that have delayed and delayed and delayed picking up SPICE, this looks VERY interesting...
:twisted:
thanks lotz