Hello amp gurus! I have a 1967 Ampeg Reverbojet (the one with faux wood paneling and copper face plate) and while there are many things I like about it, it is too ice picky. Even my jazz box has ice pick! The amp is pretty much unusable with the tone set above 2. I already had a local, respected tech go through it, and he replaced the filter caps, put in some new jacks, fixed something in the power supply, and tested the tubes. After all this work, the amp sounded exactly the same. I feel reasonably certain the correct circuit diagram can be found at http://el34world.com/charts/Schematics/files/ampeg/Ampeg_J12R.pdf I have already tried a speaker swap (to a Cannabis Rex) and while I loved the efficiency of the new speaker, it didn't really change the tone. Apparently, the old CTS speaker has a frequency response similar to the Cannabis Rex. The volume and tone pot seem to work as they should. By that I mean there is no scratchiness, the taper is appropriate, and they work through the full range of motion. This leads me to think the fault is either bad design, or capacitors. My basic questions are: 1. Could capacitors in the preamp be faulty, leading to the icepick sound? 2. Are the RC values in the diagram reasonable? 3. The volume and tone interact with each other (looking at the circuit diagram this is not surprising). Is there a way to minimize this? 4. Would using a 5751 as the preamp tube help? Many thanks for any suggestions or advice.