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What are the best pots and why?

#26
scottyd said:
You sure about that?? :eyebrow:

Link Removed
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Jonathan Harerra on bassplayer.tv said:
All of the circuitry is active here, including the volume control, so it isn't a conventional volume pot, potentiometer, which passively rolls off volume, it's an active control.
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He's not saying here that it's an "active pot." He is saying that it's an "active control," as opposed to a passive control. My first guess is that rather than passing the audio through a pot, making a passive volume control, there may be a control signal fed thru the pot, which affects an active volume circuit, like a transistor or VCA, thus making an active volume control. Second guess is that JH doesn't quite know what he's talking about. Third guess is whatever David from Audere says is the actual case, if he chimes in here. ;)

scottyd said:
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This is not an "active potentiometer." Regardless what they call it at the top of the page, it is an preamplifier circuit. Maybe in some circles of audio DIY they call these things "active potentiometers?" But my background is as a pro audio engineer and technician, and in my experience and training "active pot" is oxymoron. That thing is a preamp, and could also properly be called a variable gain line level booster.

PS looks like a cool audio DIY site.
 
#27
Yeah hopefully David will chime in, because I'm really interested in what the truth is. They may not even be called pots for that matter.....I would love to have some for my builds if they indeed work like normal pots. I’ve never seen them offered by any vendors. With such a small footprint cavity size could be made significantly smaller which is always a good thing. All I know is they are not your average every day pots! :p
 
#30
All of our controls are "active" - so what does that mean?

I will use as an example – a balance control
But all of our controls work this way.

With most preamps:
Your pickups are connected directly to a set of 2 cross wired pots.
These pots combine the 2 signals together and this feeds the next stage.

Many players complain that this creates only 3 different sounds - all neck, both, all bridge.
So you see bass designers in some cases removing the balance pot and moving toward a 3-4 etc way switch to combine the pickups (for example, Dingwall)
Next the signal most commonly flows into the preamp but sometimes into a volume control first.

With an Audere preamp:
The signal from each pickup is connected directly to 1 of 2 amplifiers in the preamp.
These amplifiers are more advanced than is typical because they must control the pickup loading.
The output of these amplifiers drive a single pot (standard passive linear taper pot) used as the balance control.
As the balance pot is adjusted the pickup will not see any change in its electrical interface - the pickups still see the same loading set by the Z-Mode control.

Since the pickups see a constant load condition now more useful sounds are created as you pan between the 2 pickups.
We get lots of complements about this because we do not “muddy” up as you pan to less than the extremes.
The output for the balance pot is again buffered before the next stage …

We are not the only preamp with an active balance control - John East, for example, does this also but it is rare because it is simply more expensive to make a preamp like this.

There is more info and a picture of this at [Invalid or Expired Link Removed] under our FAQ info.

So we use typical (well better than typical but) passive pots that are driven by active circuits.

On the technical side - a VGA (variable gain amplifier) with a DC control circuit is often used to replace pots with an active circuit. This is commonly used when signals are much faster than audio so a pot would be deadly due to capacitance effects etc. The DC control signal now will not be affected by any capacitance changes. I have designed VGAs into oscilloscopes circuits when I worked for Tek. More commonly you just put the "adjustment" under software control so it does not really matter how the adjustment is physically implemented to get the best performance tradeoffs.
 
#32
he appears sort of like when Dorothy wanted to go home, just think good thoughts....LMAO

Audere said:
All of our controls are "active" - so what does that mean?

I will use as an example – a balance control
But all of our controls work this way.

With most preamps:
Your pickups are connected directly to a set of 2 cross wired pots.
These pots combine the 2 signals together and this feeds the next stage.

Many players complain that this creates only 3 different sounds - all neck, both, all bridge.
So you see bass designers in some cases removing the balance pot and moving toward a 3-4 etc way switch to combine the pickups (for example, Dingwall)
Next the signal most commonly flows into the preamp but sometimes into a volume control first.

With an Audere preamp:
The signal from each pickup is connected directly to 1 of 2 amplifiers in the preamp.
These amplifiers are more advanced than is typical because they must control the pickup loading.
The output of these amplifiers drive a single pot (standard passive linear taper pot) used as the balance control.
As the balance pot is adjusted the pickup will not see any change in its electrical interface - the pickups still see the same loading set by the Z-Mode control.

Since the pickups see a constant load condition now more useful sounds are created as you pan between the 2 pickups.
We get lots of complements about this because we do not “muddy” up as you pan to less than the extremes.
The output for the balance pot is again buffered before the next stage …

We are not the only preamp with an active balance control - John East, for example, does this also but it is rare because it is simply more expensive to make a preamp like this.

There is more info and a picture of this at [Invalid or Expired Link Removed] under our FAQ info.

So we use typical (well better than typical but) passive pots that are driven by active circuits.

On the technical side - a VGA (variable gain amplifier) with a DC control circuit is often used to replace pots with an active circuit. This is commonly used when signals are much faster than audio so a pot would be deadly due to capacitance effects etc. The DC control signal now will not be affected by any capacitance changes. I have designed VGAs into oscilloscopes circuits when I worked for Tek. More commonly you just put the "adjustment" under software control so it does not really matter how the adjustment is physically implemented to get the best performance tradeoffs.
Click to expand...
 
#34
The best pots available are Honeywell, formerly Clarostat, formerly Allen-Bradley. They are pretty pricey, but you get what you pay for. The only drag is that you cannot solder to the back of their stainless-steel cases, so in order to establish a ground for the pot case, you need to use a ring lug around the bushing.

The "damped" feel is not an indication of how good a pot is, and the Honeywell pots feel ACCURATE, but not damped.

In the earliy days of Tapco, back in the 70's, when Greg Mackie was building mixers in his garage, he shot silicone damping fluid into the bushings of garden-variety CTS pots to give them a cushy feel. It was STILL a CTS pot, just felt better.

If you are looking for nice-feeling pots that are pretty good, Mighty Mite has them. I got some samples at NAMM, and they are pretty cool.

CTS? American? Don't let the "Chicago Telephone Supply" moniker fool you. CTS pots are made in Mexico. STILL North American, but sorry, NOT USA.

CTS, Alps, Alpha and Bourns are all on the same level. Bourns has just released a series of pots for guitars.

A good place to obtain pots from is Mouser Electronics. Also good, if you want to buy in quantity or custom configurations is State Electronics.
 
#37
J.D.B. said:
CTS, I'd rather feed Americans!
Josh
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I'm all for that!! It would seem that BOTH of my tone pots on my 1975 Carvin SB60 bass are gonna need to be replaced this year. I've noticed that they are no longer very effective in tonal variation. The bass has two passive hum-cancelling pickups with a 3-way toggle selector switch .. pretty basic design for sure.

I'd love some suggestions on replacement tone pots. Thanks

-Rob
 
#38
I gotta point out another one. PEC(Precision Electronic Components) Made in Canada. I've used their 2 watt ones on an amplifier I built, and they're some of the nicest I've ever played with.

They're bigger than most pots due to the fact that they're 2W, but feel VERY solid and well built. They're a carbon pot, which you can actually feel as you turn them. They have a lot of drag, much more tension on the wiper than most pots(consistent though, so not a bad thing IMO). So if you're looking for smooth as in little resistance, look elsewhere. I think the stiffness will be good on a bass, since it's much harder to accidentally move a control.

Available from digikey.com (or .ca if you're here in Canada)

I bought some for the bass I'm building right now. They're expensive at about $12 each, and I think the shafts are bigger than most guitar pots. (I had to drill a knob slightly to make it fit), but they feel like they'll last a very long time. Worth it IMO.

the 500k log ones I bought are part number KA5041S28. Be careful, because they've got other versions with really long shafts and stuff, and are a bit of a PITA to cut to length since they're stainless steel, not cheap pot metal.

also they've got a lower wattage one, but they're kind of weird shaped and I haven't tried them.

Digikey's also pretty good shipping-wise to those of us in Canada. Unlike many(most) companies in the US, they give us reasonably priced and VERY VERY fast shipping.
I've frequently ordered around 5pm PST, paid the $8 flat rate shipping, and gotten my stuff delivered the next morning, even when it's been shipped from Minnesota.

-Nick
 

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