On Tue, 10 Nov 2009 22:19:41 +1100, "Phil Allison"
wrote:


"Dave Plowman (Nutcase Charlatan)

If you swap 1&3 (both channels) the pot will just work in reverse.


** Only linear pots can be so easily reversed - IDIOT !!

Special " reverse log " or " anti-log " pots are needed to do what you
say.




..... Phil




A reverse connected pot will do exactly what Dave said it would. No
special pot is needed. The change in level vs rotation won't be the
same, but that is an entirely different and irrelevant matter.

d

In article ,
Phil Allison wrote:

"Dave Plowman (Nutcase Charlatan)

If you swap 1&3 (both channels) the pot will just work in reverse.


** Only linear pots can be so easily reversed - IDIOT !!


Really? What makes *any* pot special so it can't be soldered
incorrectly? And did I state it would work 'normally' but in reverse?
I rest my case, M'lud...

Special " reverse log " or " anti-log " pots are needed to do what
you say.

If you'd gone to the bother of sourcing an anti-log pot I'd assume
you knew what it would do.

Oh - and if you gave the matter some thought, it's possible wiring the pot
in reverse might make setting the *required* level *easier*, since it's
being used as a preset. But thinking never was your strong point.




..... Phil

--
*Why is it called tourist season if we can't shoot at them?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (Nutcase Charlatan)

If you swap 1&3 (both channels) the pot will just work in reverse.


** Only linear pots can be so easily reversed - IDIOT !!


And did I state it would work 'normally' but in reverse?


** What you said is right here to be seen.

And is 100% WRONG !!



Special " reverse log " or " anti-log " pots are needed to do what
you say.

If you'd gone to the bother of sourcing an anti-log pot I'd assume
you knew what it would do.

** Total red herring.

Rest of this lying charlatan's insane drivel delivered to the sewer.



... Phil

"Phil Allison" wrote in message
...
"Dave Plowman (Nutcase Charlatan)


Rest of this lying charlatan's insane drivel delivered to the sewer.


Of course your original problem Phil is that that you read more into Dave's
post than was actually there, and then found fault with the bit you'd added.
There was, in fact, nothing wrong with what he *actually* said.

But you cannot admit your mistakes. So all you can do is produce a string of
obscenities whenever you are shown to be wrong.

Have a nice day :-)

David.

Phil Allison wrote:


Rest of this lying charlatan's insane drivel delivered to the sewer.


What a funny little person you are.

"Dave Plowman (News)" wrote

Swap 2&3 and you will likely get strange frequency response errors plus
possibly distortion near zero.

Using pots like that: ie. with the signal applied to the slider and
extracted from the non-earthy end of the track, is not unknown. It was faily
common in early "transistorised" radios and record players etc. And it also
has advantages for simple audio mixers which don't use a virtual-earth
summing amp.

David.

On Tue, 10 Nov 2009 12:04:43 -0000, "David Looser"
wrote:

"Dave Plowman (News)" wrote

Swap 2&3 and you will likely get strange frequency response errors plus
possibly distortion near zero.

Using pots like that: ie. with the signal applied to the slider and
extracted from the non-earthy end of the track, is not unknown. It was faily
common in early "transistorised" radios and record players etc. And it also
has advantages for simple audio mixers which don't use a virtual-earth
summing amp.

David.


The mixing solution I used before I discovered the virtual earth
amplifier was to connect the pots the usual way, but add a resistor in
series with the slider so it would not impose a short when turned all
the way down.

I've never seen a circuit (except inside some guitars for various odd
tonal reasons) that used a configuration that put the signal into the
slider.

d

"Don Pearce" wrote in message
...
On Tue, 10 Nov 2009 12:04:43 -0000, "David Looser"
wrote:

"Dave Plowman (News)" wrote

Swap 2&3 and you will likely get strange frequency response errors plus
possibly distortion near zero.

Using pots like that: ie. with the signal applied to the slider and
extracted from the non-earthy end of the track, is not unknown. It was
faily
common in early "transistorised" radios and record players etc. And it
also
has advantages for simple audio mixers which don't use a virtual-earth
summing amp.

David.


The mixing solution I used before I discovered the virtual earth
amplifier was to connect the pots the usual way, but add a resistor in
series with the slider so it would not impose a short when turned all
the way down.

I've never seen a circuit (except inside some guitars for various odd
tonal reasons) that used a configuration that put the signal into the
slider.


Early semiconductor small-signal amplifier stages often used a single
germanium transistor in a grounded emitter configuration, with a low
resistance bias network connected to the base. Such a stage has a lower
input than output impedance. In those circumstances it makes sense to run
the volume control "backwards", as the control is turned down the pot loads
the relatively high output impedance of the preceding stage. And simple
mixers often work run that way, each input is applied, via a resistor, to
the slider of a pot. And the output is taken from the tracks of all the pots
wired in parallel. It has some advantages compared to the way you did it.

David.

On Tue, 10 Nov 2009 12:22:32 -0000, "David Looser"
wrote:

"Don Pearce" wrote in message
...
On Tue, 10 Nov 2009 12:04:43 -0000, "David Looser"
wrote:

"Dave Plowman (News)" wrote

Swap 2&3 and you will likely get strange frequency response errors plus
possibly distortion near zero.

Using pots like that: ie. with the signal applied to the slider and
extracted from the non-earthy end of the track, is not unknown. It was
faily
common in early "transistorised" radios and record players etc. And it
also
has advantages for simple audio mixers which don't use a virtual-earth
summing amp.

David.


The mixing solution I used before I discovered the virtual earth
amplifier was to connect the pots the usual way, but add a resistor in
series with the slider so it would not impose a short when turned all
the way down.

I've never seen a circuit (except inside some guitars for various odd
tonal reasons) that used a configuration that put the signal into the
slider.


Early semiconductor small-signal amplifier stages often used a single
germanium transistor in a grounded emitter configuration, with a low
resistance bias network connected to the base. Such a stage has a lower
input than output impedance. In those circumstances it makes sense to run
the volume control "backwards", as the control is turned down the pot loads
the relatively high output impedance of the preceding stage. And simple
mixers often work run that way, each input is applied, via a resistor, to
the slider of a pot. And the output is taken from the tracks of all the pots
wired in parallel. It has some advantages compared to the way you did it.

David.


Still a strange topology. What normally happens when you load down a
transistor stage with too low an impedance is massive distortion
because of the asymmetric sink/source current drive capacity.

d