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I have a 1993 Vox AC30 TB /6 amp where the Vib/Trem effect speeds up after the amp warms up. For the first 10 minutes of playing the speed for each setting (Vib and Trem) matches what is hear in this video: https://youtu.be/on1s6UjUCPY?t=231 After 15 minutes, each speed selection increases 2x or so.
I have read this thread https://archive.ampage.org/threads/6..._C_Crap-1.html which was very helpful in understanding the circuit. Rick Erickson mentions that: “I have noticed also that many of the RI AC30's have rather unstable ceramic caps in the oscillator circuit and the osc. speed will vary considerably with temperature changes. A can of freeze mist and a heat gun are very handy troubleshooting tools for this kind of work.”
This is indeed the case for me too, I spray a bit of freeze mist on the ceramic caps in the oscillator circuit and the speeds comes back to normal. I have replaced the .01uf ceramic caps with new ones and this has not made any difference. Any other suggestions? Are there any specific caps that prevent this issue? I’m pulling my hair out trying to get the Vib/Trem speeds stable. Thanks, Ross
I have read this thread https://archive.ampage.org/threads/6..._C_Crap-1.html which was very helpful in understanding the circuit. Rick Erickson mentions that: “I have noticed also that many of the RI AC30's have rather unstable ceramic caps in the oscillator circuit and the osc. speed will vary considerably with temperature changes. A can of freeze mist and a heat gun are very handy troubleshooting tools for this kind of work.”
This is indeed the case for me too, I spray a bit of freeze mist on the ceramic caps in the oscillator circuit and the speeds comes back to normal. I have replaced the .01uf ceramic caps with new ones and this has not made any difference. Any other suggestions? Are there any specific caps that prevent this issue? I’m pulling my hair out trying to get the Vib/Trem speeds stable. Thanks, Ross
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