Per adventure I have to replace the original 22k bias pots on my R8 with the higher quality, 10k Vishay pots.
The SD Muzishare X7 video "Replacing the Tube Bias Potentiometers" (https://m.youtube.com/watch?v=CuCeE2EdMi4) describes a solution by which 5k and 18k resistors are implemented to allow for the use of 10k pots. Excellent video!
As I understand it, the same thing can be implemented on my R8, but I have no idea how to do it. The bias boards are completely different. So, I asking for help from any and all who can point out where those 5k and 18k pots would go on the R8 bias board and which wire(s) I would then need to hook up to those respective resistor arrays?
Assume I am a complete idiot when it comes to this because, you know, I am. 🙂
By way of reference, here is a pic of the V3 & V4 bias board from my R8....
Thanks for any help you can give! And special thanks to Skunkie Designs for her inspirational videos!
Thank you for that clear, easy to follow solution. Just like your videos.
And yes, I've already sourced resistors for the safety measures. I've watched all your R8 videos, and took your advice to heart. Starting with the output upgraded resistors and the bias boards and pots. Front end next.
Thanks again.
The original R8 schematic shows a 15K pot but if I was going from a 22K to a 10k, I would simply add 5K to each resistor on each side of the pot, replace the 1.2K with a 5.1K (closest value) and the 22K with a 27K. Also make sure you add the 100K safety resistor between the power side pin of the pot and the center tap. I show how to do this in another video about "Must do mods" or something like that.
Could it be as simple as replacing the 22k resistors with 10k, thus foregoing the need for the 5k and 18k resistors?