Is that much of a concern in this particular application?
Also, are any of them non-inductively wound? Not sure how you'd pull that off in a potentiometer. And if they're not, how would that inductance effect cartridge loading? They'd certainly be good at picking up stray magnetic fields unless they were well shielded.
se
I wouldn't think so- a potentiometer would nearly always be at the same temperature along the track (assuming it's not abused), and it's ratiometric...
I use multigand trimmers in my circuits to trim for DC and minimum distortion.
Usually i use Spectrol ( now Vishey).
I use them in the signal chain with a resistor parallel. So when i have a resistor of say 470 Ohm i use a 5kOhm pot in parallel ( just an example).
That way i limit the pot range, so when it is a little bit of it is not a tragedy.
Performance wise i am happy with that configuration.
Usually i use Spectrol ( now Vishey).
I use them in the signal chain with a resistor parallel. So when i have a resistor of say 470 Ohm i use a 5kOhm pot in parallel ( just an example).
That way i limit the pot range, so when it is a little bit of it is not a tragedy.
Performance wise i am happy with that configuration.
I hope to use these potentiometers in rheostat mode that will emulate a changing resistance. Therefore, tempco could be important. The digital readout might drift, and upset the customer. I also welcome suggestions of how best to series and parallel fixed resistors for optimum operation.
What about the magnetic resistance wire and inductance? Or are you just talking about pots in general?
se
se
The pots that I have looked at have +/- 100 ppm tempco, and are essentially non-magnetic. I would avoid a really magnetic material as the fundamental material in a pots construction.
From your original comment, it seemed you wished to have a discussion regarding the use of wirewounds for cartridge loading. But judging by this comment, apparently you don't.
So why'd you bring them up in the first place?
se
Steve, I would appreciate real information based on experience from other design engineers. If someone has actually used these hybrid pots, then I would value their input. I already know how to Google a data sheet, as you apparently have. I also have experience with multiturn wirewound pots as volume controls, so I know that they work well at line level, and I have various examples of multiturn wirewound pots at hand.
So my actual question is not directed at you, unless you have some actual experience with multiturn HYBRID wirewound pots, for better or worse.
Is there anyone else out there, who has some experience with these hybrid pots in audio circuitry?
So my actual question is not directed at you, unless you have some actual experience with multiturn HYBRID wirewound pots, for better or worse.
Is there anyone else out there, who has some experience with these hybrid pots in audio circuitry?
John,
ONLY if you would actually 'measure' the resistance and feed that back to the read-out, which would be an awkward way to do it; it's never done that way AFAIK. So, using this as a termination for the cartridge, you probably wouldn't worry about it drifting a fraction of a percent.
jd
I am personally not concerned with drift with temperature, but in measuring traditional ww pots, I do find the lack of resolution at low resistance settings, disturbing.
OK, anybody has the right to change their mind 😉
So what resistance range are you looking at, and what resolution do you need?
jd
Jan, I am looking for suggestions, rather than general evaluations, as well as personal experience. Since the tempco of these pots is pretty good, and the enclosure will not change appreciably in temperature, as it will be on continuously, I am NOW not concerned about appreciable drift in this pots.
Wirewound pots and to a lesser extent hybrids sometimes have funky behavior at stop values. Assuming you want a non linear response to give you better matching at specific values, you will of course also be using a network of fixed resistors around the pot. Bourns showed some examples in their Ap book years ago. But without details about the range of values required it is hard to suggest a specific model or brand.
The material used for the base resistance wire changes depending on range.
Of course I suspect everyone is aware of the long term bad effects of any DC on the wiper.
The material used for the base resistance wire changes depending on range.
Of course I suspect everyone is aware of the long term bad effects of any DC on the wiper.
Yes but you must have SOME idea of the range of values you're looking for?
Termination of a cartridge, I'm no expert there but I guess low kohms to 10's of ohms?
jd
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