Conductive Plastic -vs-Cermet Potentiometers
Oct 13, 2010 at 6:58 PM Thread Starter Post #1 of 3

Zaubertuba

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The last stage of my preamp/headphone amp project will be controlled with a pair of nice P&G Faders I found on eBay.
 
The input stage (it will actually pull double duty as a hifi instrument preamp) may require up to *7* pots per channel (a 4-band parametric plus an opto compressor/limiter circuit).
 
I don't have the money to purchase P&G pots throughout, but I don't want to degrade signal quality excessively (otherwise, why use the P&G faders in the first place?).
 
So, I'm looking at lower-end alps, and BI Industries makes some surprisingly inexpensive conductive plastic pots that have gotten some good reviews elsewhere.  Can anybody speak to general sound quality of conductive plastic vs cermet pots?
 
Oct 15, 2010 at 2:05 PM Post #2 of 3
Implementation is everything.  
 
Edit: sorry, that may not have been particularly helpful without context.  With respect to potentiometers, you want a gadget that works well, so who cares about the material in question?  General comments, eh.  A good gadget, great.  I would also suggest that 7 pots per channel is a pretty serious constraint (both on cost and quality).  If there is a way to decrease the number of pots required, that might yield the greatest benefit.
 
Oct 15, 2010 at 6:46 PM Post #3 of 3


Quote:
Implementation is everything.  
 
Edit: sorry, that may not have been particularly helpful without context.  With respect to potentiometers, you want a gadget that works well, so who cares about the material in question?  General comments, eh.  A good gadget, great.  I would also suggest that 7 pots per channel is a pretty serious constraint (both on cost and quality).  If there is a way to decrease the number of pots required, that might yield the greatest benefit.


That's the difficult part, isn't it?  Catch is, for a "hi-fi" or audiophile preamp, the minimalist approach seems to be the most effective.  For an instrument preamp, there's the real-world hurdles of bad room acoustics, group blend and balance, reinforcement dynamic, and of course the spectre of "finding the ideal tone."  EQ/compression/distortion (and to a lesser degree other special effects an electric instrument musician may add) are all parts of this equation, and each stage adds more pots (and a lot of other stuff) into the signal chain.
 
To have an idea of the application, you may want to check out the block diagram in my build thread here: http://www.head-fi.org/forum/thread/450726/a-stereo-instrument-preamp-headphone-amp-formerly-a-jisbos-with-gain-headamp/90#post_6942087.
 

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