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02-25-2019, 05:38 PM
Hi makinrose
For the most part, most brands of pot are pretty reasonable and the cost=quality notion is itself not entirely reliable. This means you can get a 25-cent pot that works well for decades and a very expensive one that fails or becomes noisy. Sometimes it is just a bad sample.
When I started building amps, I used whatever pots were available to me from local suppliers, or from broadline vendors as I found out about them. A lot of custom stuff and mods were done using "no name" pots. When I started building amps as company products, I standardised on PEC pots because they were needed for the Power Scale circuits I was using at the time. These are 28mm with smooth shafts as standard - no options for knurled shafts, just for shaft length when buying quantities.
PEC went a bit nuts with their pricing, so I designed them out and switched to 16mm pots everywhere. My local suppliers carried Alpha-Taiwan pots but the shaft lengths would vary with the pot value and taper. Needless to say, you want pots with uniform mechanical characteristics so you can use one style and type of knob. I found a Chinese supplier that I still use today and I can get the shaft length I prefer with knurled shafts that match the knobs I use.
When choosing pots, you have to keep in mind what knob you want to use. For example, when modifying Marshalls, you can buy Marshall knobs that have a set screw and fit 1/4" smooth round shafts, and knobs that are push-on to fit a T18 knurled shaft. This allows you to mix pots that are physically different. I'm seeing more styles of knobs that come in both set-screw and push-on forms, which greatly alleviates some of the problems amp builders and modifiers have finding such things.
For the hifi stuff I build, I use 1k linear and log pots from Bourns that are 9mm. I get these from Mouser.
For the most part, most brands of pot are pretty reasonable and the cost=quality notion is itself not entirely reliable. This means you can get a 25-cent pot that works well for decades and a very expensive one that fails or becomes noisy. Sometimes it is just a bad sample.
When I started building amps, I used whatever pots were available to me from local suppliers, or from broadline vendors as I found out about them. A lot of custom stuff and mods were done using "no name" pots. When I started building amps as company products, I standardised on PEC pots because they were needed for the Power Scale circuits I was using at the time. These are 28mm with smooth shafts as standard - no options for knurled shafts, just for shaft length when buying quantities.
PEC went a bit nuts with their pricing, so I designed them out and switched to 16mm pots everywhere. My local suppliers carried Alpha-Taiwan pots but the shaft lengths would vary with the pot value and taper. Needless to say, you want pots with uniform mechanical characteristics so you can use one style and type of knob. I found a Chinese supplier that I still use today and I can get the shaft length I prefer with knurled shafts that match the knobs I use.
When choosing pots, you have to keep in mind what knob you want to use. For example, when modifying Marshalls, you can buy Marshall knobs that have a set screw and fit 1/4" smooth round shafts, and knobs that are push-on to fit a T18 knurled shaft. This allows you to mix pots that are physically different. I'm seeing more styles of knobs that come in both set-screw and push-on forms, which greatly alleviates some of the problems amp builders and modifiers have finding such things.
For the hifi stuff I build, I use 1k linear and log pots from Bourns that are 9mm. I get these from Mouser.
