Hi all,
I got a simple question, but necessary: I want to replace the old VRs of an amp with those multi-turn, much more precise. Originals are 3.3k ohms but I can only find here the 4.7k ohms part. Do I have to put exacly the same value, or is 4.7k ok? Or 2.2k as well?
Thanks a lot!
I got a simple question, but necessary: I want to replace the old VRs of an amp with those multi-turn, much more precise. Originals are 3.3k ohms but I can only find here the 4.7k ohms part. Do I have to put exacly the same value, or is 4.7k ok? Or 2.2k as well?
Thanks a lot!
As is so often in engineering, "it depends .." 😀
If the pot is used like a volume control - signal at the top, ground at the bottom, wiper picking off a voltage between the two, the resistance value is almost certainly not at all critical, within reason.
If it is part of a filter circuit with other Rs and Cs around, it might be more critical, so needs to be examined.
I've never seen a 3K3 pot used in other than bias or offset adjustments, so I very much doubt that its value is critical.
Go for a higher value, 4K7, and I'm sure it will be fine.
Publish a circuit snippet, and we can be more definite.
Cliff
If the pot is used like a volume control - signal at the top, ground at the bottom, wiper picking off a voltage between the two, the resistance value is almost certainly not at all critical, within reason.
If it is part of a filter circuit with other Rs and Cs around, it might be more critical, so needs to be examined.
I've never seen a 3K3 pot used in other than bias or offset adjustments, so I very much doubt that its value is critical.
Go for a higher value, 4K7, and I'm sure it will be fine.
Publish a circuit snippet, and we can be more definite.
Cliff
Thanks, Cliff!
You're right! It's for the Bias in an Yamaha amp. I need a multi-turn pot suitable for this purpose. So, I guess a 4.7k would be fine, right? 🙂
Picture below:
An externally hosted image should be here but it was not working when we last tested it.
Use a higher value pot and put a fixed resistor in parallel to reduce the combined value to the 3K3 ohms. This way you will not exceed the bias current of the original design when the pot is at max R. E
Nice! The fixed resistor would go between the two other pins (not the wiper), right?
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