Archive of the former Yahoo!Groups mailing list: MOTM

----- 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