clintrubber
Well-known member
Hi,
FWIW, I've been toying around a bit with the levels of
the Green LED-bar.
Personal preference (that's just me) is to have a smaller steps,
of say 10 dB i.s.o. the original 20 dB (obviously a smaller range results).
I've done a quick & dirty redimensioning - I thought I'd share in case
this happens to suit someone else as well.
Here's what I came up with. Taps are a bit less accurate than the original
(Peter C has found a real nice set of values with standard E12-range resistors !),
but the following is still within 0.1 dB (0.3 dB for the lowest tap) so
that's still accurate enough.
Orig set: 47 / 100 / 10 / 1 / 0.12 [kOhm]
Modified set: 39 / 56 / 18 / 5.6 / 2.7 [kOhm]
Non E12-values could of course be used for further increased accuracy but hey,
the summer is beginning - don't stay too long inside recalculating for even
higher accuracies - it really doesn't matter anymore beyond this (to say the least).
Original taps (@ trimmed for orange LED @ 0 dBu): +20 / 0 / -20 / -40 [dBu]
Modified taps (@ trimmed for orange LED @ 0 dBu): +20 / +10 / 0 / -10 [dBu]
This all might seem an odd modification, but I'll be mainly using this preamp directly
to a HDD-recorder with inputs of 0dBu_typ/12dBu_max so a downward shifted and/or
reduced meter range suits me better.
A 10 dB shift downwards w.r.t. the modified set of taps is done by the 100k trimmer.
We finally get this then: +10 / 0 / -10 / -20 [dBu].
Regards,
Peter
FWIW, I've been toying around a bit with the levels of
the Green LED-bar.
Personal preference (that's just me) is to have a smaller steps,
of say 10 dB i.s.o. the original 20 dB (obviously a smaller range results).
I've done a quick & dirty redimensioning - I thought I'd share in case
this happens to suit someone else as well.
Here's what I came up with. Taps are a bit less accurate than the original
(Peter C has found a real nice set of values with standard E12-range resistors !),
but the following is still within 0.1 dB (0.3 dB for the lowest tap) so
that's still accurate enough.
Orig set: 47 / 100 / 10 / 1 / 0.12 [kOhm]
Modified set: 39 / 56 / 18 / 5.6 / 2.7 [kOhm]
Non E12-values could of course be used for further increased accuracy but hey,
the summer is beginning - don't stay too long inside recalculating for even
higher accuracies - it really doesn't matter anymore beyond this (to say the least).
Original taps (@ trimmed for orange LED @ 0 dBu): +20 / 0 / -20 / -40 [dBu]
Modified taps (@ trimmed for orange LED @ 0 dBu): +20 / +10 / 0 / -10 [dBu]
This all might seem an odd modification, but I'll be mainly using this preamp directly
to a HDD-recorder with inputs of 0dBu_typ/12dBu_max so a downward shifted and/or
reduced meter range suits me better.
A 10 dB shift downwards w.r.t. the modified set of taps is done by the 100k trimmer.
We finally get this then: +10 / 0 / -10 / -20 [dBu].
Regards,
Peter