----- Original Message ----- From: Eric Frampton <eric@...> I don't have a frequency counter that'll go up to the high end that one is supposed to cal ..... Has anybody figured out a way to calibrate that trimmer without a frequency counter? ----- Original Message ----- From: John Blacet <blacet@...> I would advise just setting the one turn trimmer to mid span and adjust the 20T for 2KHz. This is hardly critical to the TM operation or sound. --LH-- Both of my Time Machine modules are calibrated to the frequency specified by John in the instructions. I measured the voltage at the bottom of R7 (I think I said top before). With no external connections (well there is that power supply thing), here are my measurements: Delay pot set to zero: TM # 1 = 0.022 TM # 2 = 0.021 Delay pot set to ten: TM # 1 = -0.118 TM # 2 = -0.119 But, as John said, the top end is not critical. When I first fired mine up (trimmer in the middle I think), my max frequency was about 250KHz instead of the 400KHz. The short end of the delay seemed short enough even at that lower frequency. I my way of thinking this is a good way to calibrate without a frequency meter. Larry H
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Re: [motm] Calibrating Time Machine?
2002-03-27 by J. Larry Hendry
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