Here's a helpful link that I found:
http://geofex.com/Article_Folders/potsecrets/potscret.htm
73,'
Bob WB2VUF
On 2/11/2011 2:28 AM, Dr. Gerald N. Johnson wrote:
> Digging out the data sheets from that maker, it shows pots with 1/4"
> shaft and 3/8" bushing, choice of two bushing lengths. That's on the
> data sheet offered by Maplin. Digging deeper the factory data sheet
> shows a reverse log pot can be had. http://www.omeg.co.uk/p20data1.htm
> Whether in quantity one I don't know.
>
> However if the pins don't match the board anyway, it might be handier to
> go with a smaller diameter pot and wire leads. I've not checked those.
>
> I don't think I've see a reverse log taper pot offered lately in US
> catalogs that I've wandered through like Mouser. Allied doesn't offer a
> dual pot of any value. But then Allied has never recovered from being
> owned by Radio Shack. Newark neglects to show mounting and shaft
> dimensions on line. Useless.
>
> 73, Jerry, K0CQ
>
> On 2/10/2011 2:17 AM, Steve Hunt wrote:
>> Charles,
>>
>> Thanks for the suggestions. I see a couple of problems:
>>
>> * The pot mounts directly to the PCB, so swapping the ends means cutting
>> tracks which I'd prefer not to do at this stage. Of course if I modified
>> it for panel-mounting then it would be easy.
>>
>> * The front panel is marked with an "Out" position with the knob fully
>> CW; in that position the AF frequency of the notch is above the filter
>> passband. Reversing the "sense" would mean that in the "Out" position
>> the notch is still within the passband, albeit at the LF end and maybe
>> not too noticeable.
>>
>> All of this makes me wonder why TT went to the trouble of using a
>> reverse log pot. It would have been as easy - and arguably more logical
>> - to have the control work the other way round: i.e. the "Out" position
>> full CCW.
>>
>> 73,
>> Steve G3TXQ
>>
>>
>>
>> On 09/02/2011 22:49, Charles P. Steinmetz wrote:
>>> Steve wrote:
>>>
>>>> I can't think of any simple way of "fudging it".
>>> You can swap the "end" contacts of the pot (i.e., cross the wires
>>> that connect them to the PC card). This will restore the original
>>> linearity, at the expense of lower frequencies being clockwise and
>>> higher frequencies being counterclockwise with the knob.
>>>
>>> Best regards,
>>>
>>> Charles
>>>
>>>
>>>
>>>
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