Tube Driver Pots -- Log/Linear Question

Started by KazooMan, December 21, 2009, 10:40:23 AM

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KazooMan


I'm building Bajaman's B K Butler Tube Driver.  The schematic and layout have the Hi and Lo tone pots as 500K log and 100K log respectively.   J D Sleep's Tube Driver schematic from the GGG site is VERY similar to Bajaman's, but shows both of these pots as being linear taper.  To add to my confusion, I found a schematic for the Chandler Rack Mount Tube Driver (an enhanced version of the original Butler with a few more features).  It has Treble (500K linear) , Mid (10K Linear) and Bass (100K log) pots.  So, for three schematics based on the same original design we have either two log pots, two linear pots, or one of each! 

Any throughts on what advantage either the linear or log pots would provide for these tone controls?  All of the designs use log taper pots for the Level and Drive controls, and that makes sense to me.

BTW.....  I am readdressing the pots issue because I have to redo my board.  This is the first double sided board project I have done and I made several rookie mistakes such as installing the tube socket before making some connections between the faces of the board that got buried.  Several cycles of desoldering and resoldering a few components and I no longer trust the board. 

Seconf BTW....  Earlier I had posted a question asking for a source for polarized header connectors.  I ended up getting them from Futurlec.  The connectors I got look fine, but they do not mate together firmly.  The sockets wiggle and the locking tabs seem useless.  They keep coming apart when I place the board in the box.  I think I will just skip them.

PRR

The circuit does not care linear or audio taper.

It is only about how the user feels.

Put in linear. Use it. If you find yourself working in the crack around "1", and very touchy, change to Audio taper.

So it depends a lot on the user. I bet the tone-stack is Fender-like. If the user likes lots of bass, then the Bass pot will never be near "1". However a user with less boomy taste might be working at "0.8" and "1.3". Then a Audio taper will move those low settings up into the "2" to "3" range. The tradeoff is that the linear "5" setting gets pushed up nearer "7" or "8".

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KazooMan



Thanks for the response.  I will follow your advice and go with the linear pots to see how the controls interaact and then switch to log pots where needed (if at all).

ppcnostalgic

Hey man, I built it following an italian guy' schematic and  it sounds awesome: