Greetings all !!
Potentiometers have become hugely expensive, apart from the old carbon types. What would members recommend for typical audio pre-amplifiers (eg: volume & tone controls, etc) ?
I would be looking for low noise, long life types. Are wire-wound pots 'over-kill' ?
thanks for any comments/advice
Potentiometers have become hugely expensive, apart from the old carbon types. What would members recommend for typical audio pre-amplifiers (eg: volume & tone controls, etc) ?
I would be looking for low noise, long life types. Are wire-wound pots 'over-kill' ?
thanks for any comments/advice
Thanks Scottjoplin,
Suppliers in South Africa seem to stock only Bourne & Vishay, I guess these would be equivalents.
Thanks again
Thanks so much RajkoM
This project comprises a Tri-Amped audio system, with a fairly elaborate preamplifier, (read 'expensive' overall) so good sonic results are demanded.
Would you go as far as to say that cermet is audibly superior to any other type - such as conductive plastic for example ?
I certainly will give cermet as well as plastic a try - although I'm not expecting to hear a great deal of difference.
Carbon pots are not an option any more, dual WW's are not common, and I think they would not yield any real advantage either. They are also very, very costly.
Thanks again,
I think cermet is 'one of the best too.
Carbon pots are second and plastic ALPS is not my preferred at all. Even a cheap carbon pot is as good or better than expensive gang/gold/silver switches, I find the price is not justified and doesn't yield any sonic benefits.
So my advice is to get a pot which tracks as good as possible the stereo channels. this will have a major impact for your pre-amp, a 2 db channel imbalance is huge and most pots have worse tracking than that.
A wire wound should be ok too but not the same feel.
I experimented with DIY industrial silver contact switches and even if the contacts are high pressure the size of the pot is not good for noise.
I tried with gold plated gang switches which are super expensive and the contacts are not so much pressure.
I find the major criteria for pot sound is how much pressure and consistency the contacts and how much area is there to catch noise and electromagnetic frequencies.
To me so far the CARBON high pressure pot (with very large traces (3mm wide)) are the best. They sound like a carbon resistor which is enjoyable. I find the ALPS blue and black to be not as good for noise and especially affect maybe psychoacoustic that I hear in two preamps that I built.
Carbon pots are second and plastic ALPS is not my preferred at all. Even a cheap carbon pot is as good or better than expensive gang/gold/silver switches, I find the price is not justified and doesn't yield any sonic benefits.
So my advice is to get a pot which tracks as good as possible the stereo channels. this will have a major impact for your pre-amp, a 2 db channel imbalance is huge and most pots have worse tracking than that.
A wire wound should be ok too but not the same feel.
I experimented with DIY industrial silver contact switches and even if the contacts are high pressure the size of the pot is not good for noise.
I tried with gold plated gang switches which are super expensive and the contacts are not so much pressure.
I find the major criteria for pot sound is how much pressure and consistency the contacts and how much area is there to catch noise and electromagnetic frequencies.
To me so far the CARBON high pressure pot (with very large traces (3mm wide)) are the best. They sound like a carbon resistor which is enjoyable. I find the ALPS blue and black to be not as good for noise and especially affect maybe psychoacoustic that I hear in two preamps that I built.
Thanks, gabdx,
An idea that has been suggested to me (by private email) is the use of step switched volume control. It's an idea that occurred to me independently too - although for different reasons. One fact is certain, with step switching, whether by a commercially made product or a diy one, it would be possible to get ideal channel balance. Commercial 24way units are very costly (and not ex stock, either) but 12 way, diy units would probably do very nicely, although two would be required for stereo.
Linear pots tend to have better matching than log, so are often used with a resistor between wiper and ground to make a "fake log law" pot. ESP - A Better Volume Control
This is good advice indeed, as is all the other responses so far.
In all probability, my preamp will use an active (Baxendall) volume control so will need linear pots anyway.
Another idea suggested is bootstrapping a linear pot with a higher value fixed resistor, such that the net resistance is at or near what is required; the varying value of pot resistance becomes a smaller component of the net value this way, and helps towards balancing the channels ....
Thanks for the link, a most interesting article !
Thanks for your input. I have never heard of that company, can you tell me if they make their pots in carbon, plastic or ceramic (cermet) ?
I am also trying to find if the "variable line out" from digital equipment is ok for good audio quality. Some say this is not recommended because the digital control of loudness involves compressing the audio signal, thus reducing the musical dynamic range - this something that mechanical pots won't do