What Is So Damn Hard About a potentiometer In LTSpice ?

[jurb...@gmail.com]

I have been up and down the road on this. It seems alot of people want this and a few have done it. I would like to just download it and put the stuff where it belongs and bah da bing. I am not a dumbass but I don't know alot about software.

I want to show my tone control set, which uses a different topology than anyone is used to. I HAVE seen it but it is rare.

A shitload of the links on this I went to in the last couple days timed out or weren't there.

Anyway, I need a pot.

[Phil Hobbs]

The usual approach AFAIK is to have two resistors in series, with a
stepped parameter, e.g.

R1 is {Rpot*ratio}
R2 is {Rpot*(1-ratio)}

and then on the schematic, type 's', and when the dialogue box appears, type

.step param ratio 0 1 0.1 ; (or whatever step you want.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

[Jim Thompson]

On Fri, 1 Jun 2018 22:49:53 -0400, Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>On 06/01/18 21:56, jurb...@gmail.com wrote:
>> I have been up and down the road on this. It seems alot of people want this and a few have done it. I would like to just download it and put the stuff where it belongs and bah da bing. I am not a dumbass but I don't know alot about software.
>>
>> I want to show my tone control set, which uses a different topology than anyone is used to. I HAVE seen it but it is rare.
>>
>> A shitload of the links on this I went to in the last couple days timed out or weren't there.
>>
>> Anyway, I need a pot.
>>
>
>The usual approach AFAIK is to have two resistors in series, with a
>stepped parameter, e.g.
>
>R1 is {Rpot*ratio}
>R2 is {Rpot*(1-ratio)}
>
>and then on the schematic, type 's', and when the dialogue box appears, type
>
>.step param ratio 0 1 0.1 ; (or whatever step you want.)
>
>Cheers
>
>Phil Hobbs

See "PotentiometerForSpice.pdf" on the Device Models & Subcircuits
Page of my website. STEP Parameter "SET".

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Thinking outside the box... producing elegant solutions,
by understanding what nature is hiding.

"It is not in doing what you like, but in liking what you do that
is the secret of happiness." -James Barrie

[bloggs.fred...@gmail.com]

Just to review: a pot is a voltage divider and rheostat is a variable resistance. If a pot is what you want, this insufferable video illustrates what you need to do, as far as I can tell. Don't bother reading any of the manual in LTSp, it's pure gibberish posing as language. https://www.youtube.com/watch?v=yfUPlEQOhlc

[gnuarm.del...@gmail.com]

On Friday, June 1, 2018 at 9:56:18 PM UTC-4, jurb...@gmail.com wrote:

Or do you need "some" pot???

If you just need a standard potentiometer, then others have described what you need to do. It's not hard. But what is special about your "topology"? I recall some very odd pots from old radios with extra taps, tone controls I seem to recall. Are you doing something like this? If you have taps on your pot and the circuit on your wiper is not high impedance, it would be hard to do in spice I think. I can't visualize a circuit to emulate this off the top of my head.

Rick C.

[jurb...@gmail.com]

>"If you just need a standard potentiometer..."

You just said more then you think. See, this pot is fed with a direct signal with 16 dB gain above line level. Regardless of the pot curve, the center is calibrated by a pot between the wiper and ground.

If this doesn't shut the audiophools up I gave up. This is a solid design and the phase problems are non existent.

Like I said it has been done, but it was some obscure tech type place up in bumfuct up north land, like Sweden or something. I shouldn't say that, because they are pretty good craftsmen. So what.

I can't really explain the whole theory of the thing without a print, so I am going to do that and throw it in here. I'll start now.

[gnuarm.del...@gmail.com]

Before you go too far, you might try posting a circuit diagram of some sort. Sounds like some ascii art is in order as it appears to be a fairly simple circuit to draw.

Rick C.

[mako...@yahoo.com]

> >>
> >> I want to show my tone control set, which uses a different topology than anyone is used to. I HAVE seen it but it is rare.
>

see tonestack

http://www.duncanamps.com/tsc/

m

[jurb...@gmail.com]

>"see tonestack

http://www.duncanamps.com/tsc/ "

Looks like something in a guitar amp.

[jurb...@gmail.com]

>"Before you go too far, you might try posting a circuit diagram of some sort. Sounds like some ascii art is in order as it appears to be a fairly simple circuit to draw. "

I can't do ASCII. I'll make a representation in LT just to get the idea out there. Of course it will never simulate but...