Express Scope Traces - too much gain?

[sdp1234]

The format of my message and screen captures were modeled after a post that Rob (rbryerton) placed back in 2010.

Currently I have some ghosting\fuzz that I need to resolve. Also I will be modifying this build to get a bit of a cleaner output because this was the goal of the person I’m building for. I plan to use what I learn to later build another Rocket (or maybe Liverpool)

Where does it clip? Where does the majority of the overdrive come from? How can I clean it up a bit at max gain? These were some of the questions I’m working with.

Rob, came to the conclusion that the best mod *for him* was simple: a micro-switch to switch in and out a 100k resistor to ground, tapped from after the 220k resistor (R10) after the tone stack.

I’m seeing much more distortion at the output and PI than Rob was seeing when he scoped his Rocket. Seems like something may be wrong with my build but I wanted to see if anyone else has checked the readings with a scope and may be able to help with what I am seeing



I've included some voltages for my Rocket that show the gain progression through the circuit, as well as many scope traces showing what the circuit does at various points.


I tested with a 200Hz, 0.100 v sine wave injected at the input jack.
It is a the Rocket circuit with a mosfet cathode follower because I didn’t have room for the additional tube.

B+1 306
B+2 266
B+3 247
B+4 207
B+5 202


Here's some pics, and I look forward to hearing any feedback.

Stage one, two and cathode follower out.

[sdp1234]

Scope traces after Tone Stack

[sdp1234]

The attached traces are showing the Phase inverter at 30%, 60% and 100% gain. Looks like the PI starts distorting right away.

[sdp1234]

Views of the PI compared to the Output at 25%, 50%, 75% and 100% gain. Look like the output starts distorting immediately. Not sure if it is from the PI or if the Output stage is distorting directly. Also there is a kink in the wave form at 100%