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Old 10th June 2018, 01:43 PM   #11
tiefbassuebertr is offline tiefbassuebertr  Germany
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Originally Posted by Professor smith View Post
I would simply like to know why passive pots lack dynamics and bass?

This has been my own experience with them and I'd like to know what kind of distortion could cause such effects?
If there are no long wires between potentiometer output and gain stage signal input in use, the quality standart of the potentiometers or switches for the resistor networks alone determines the sound quality.
For example - a rotary switch from Lorlin produces costs arround 1 US-$, while Shallco, ELMA or Seiden produces costs of 100 to 200 Lorlin switches for one unit. Similar situation are to observe at potentiometers (compare Piher, Alps and Penny/Giles)
The fact that differences in sound quality occur at these differences at costs, is actually self-evident (bad contact quality means bad sound).
That's why even commercial passive pre-amplifiers with only two rotary switches are extremely expensive - go to post #26 under
passive preamp

If there are additional long shielded wire between potentiometer output and gain stage signal input in use (e. g. to a pair of monaural power amplifiers), there are an unwanted parasitic low pass filter effect (dependend of the potentiometer position),which creates even lack dynamics on sound impression.
Therefore I am looking to a TVC approach for a passive preamp with gain factor below unity gain (between 0,2 and 0,6), but which is suitable for long shielded cables.
Who know such TVC's ?
Thank you for advices.

Last edited by tiefbassuebertr; 10th June 2018 at 01:54 PM.
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Old 10th June 2018, 02:15 PM   #12
Zen Mod is offline Zen Mod  Serbia
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passive attenuator
buffer in front of AVC

no need for TVC, except if you want galvanic isolation
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